Philosophy
Higher
Epistemology
NQ Support Material
2006
Scottish Further Education Unit
Support Notes: Philosophy: Epistemology (Higher)
Acknowledgements
SFEU (Scottish Further Education Unit) gratefully acknowledges the contribution made to
this publication by Learning and Teaching Scotland who have granted permission to use
material previously produced by HSDU.
SFEU also thanks SQA for permission to reproduce parts of the Arrangement
Documents.
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Support Notes: Philosophy: Epistemology (Higher)
Contents
Introduction
4
Statement of Standards
6
Tutor Support Section
8
1.
Teaching Outline
9
1.1
1.2
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9
Time Allocation
Delivery Outline
2.
Learning and Teaching Approaches
11
3.
Guide to Resources
12
3.1
12
Books
Student Support Section
14
Section 1 – Introduction to Epistemology
The Tripartite Theory of Knowledge
Problems with Justified True Belief
Scepticism, Rationalism and Empiricism
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21
Section 2 – René Descartes – The Method of Doubt
Descartes’ Method
Descartes’ Mistrust of the Senses
The Dreaming Argument
Limitations of the Dreaming Argument
Demons and Virtual Reality
Rebuilding Knowledge
The Role of God
Critical Evaluation of Descartes
Descartes’ Argument – A Summary
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40
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45
Section 3 – David Hume
The Egocentric Predicament
Impressions and Ideas
Impressions and Ideas II
Simple and Complex Ideas
No Innate Ideas!
The Missing Shade of Blue
Hume’s Fork
Habits of Thinking
The Problem of Induction
Critical Evaluation of Hume
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Introduction
Scotland has long been recognised as providing educational opportunities to its citizens
that encompass both breadth and depth. The need to educate the whole person, and not
simply concentrate on immediately obvious practical skills, is also firmly embedded in all
Scottish educational philosophy. As a result, education focuses on the dual objectives of
providing citizens with practical skills and knowledge related to employment, and broader
intellectual and social skills which enable them to participate fully in society and lead rich,
fulfilling lives. It is also recognised that these broader skills are increasingly important as
societies become more complex and ideologically diverse. Scottish society today has
been influenced by a wide variety of cultures and traditions, and it is therefore important
that all its citizens are able to develop and express their own values and perspectives in a
reasoned way. In addition, it is important that they are able to discuss and reflect upon
perspectives and values which may be different from their own. This can only be
accomplished through a process of reasoned debate and discussion which acknowledges
shared human experiences and also the validity of alternative views. Developing a
structured approach to all forms of discourse will contribute to this process.
The opportunity for individuals to develop and discuss their own values and perspectives,
and learn to appreciate those of others, is an important aspect of Scottish primary and
secondary education. For this reason the process of discussion, debate and reflection
features in many areas of the curriculum from P1-S4. The Intermediate 2 Philosophy
Course provides the opportunity for candidates to continue to develop the concepts and
skills needed for productive social discourse and offers certificated progression in S5 and
S6. The Course is also suitable for delivery in further education colleges and is
appropriate for adult students who have an interest in philosophical issues.
Candidates who gain a Course award will be in a good position to continue their studies
of philosophical issues at Higher level or in further education colleges. Those who choose
to progress to study alternative subjects will also benefit. Developing basic critical thinking
skills and the ability to reason in a structured way is an important part of the Intermediate
2 Philosophy Course and these skills are of relevance in all subject areas. This will help
candidates to develop as members of society who can express their own opinions and
values confidently but also appreciate the opinions and values of others.
The Course consists of four mandatory Units. The Critical Thinking in Philosophy Unit
helps candidates to develop an understanding of good and bad arguments and develop
basic reasoning skills. In the Metaphysics Unit candidates investigate aspects of a
perennial philosophical debate and some of the positions adopted in relation to that
debate. The Epistemology Unit focuses on questions surrounding the nature, sources and
possibilities of knowledge. Moral Philosophy involves the study of issues and theories
concerning moral judgements.
Aims
The Course aims to allow candidates to:
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•
•
develop basic critical thinking skills which are of importance in all areas of human life
and discourse
develop knowledge and understanding of basic philosophical techniques, issues,
positions and concepts which are relevant in many areas of human life and discourse
develop basic analytical and evaluative skills which help them to begin to examine the
reasoning and assumptions on which the positions and theories they study are based
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•
•
•
present their own ideas and opinions confidently and in a reasoned manner
gain insight from the ideas and opinions of others which may conflict with their own
engage personally with a range of important questions and issues in order to inform
their own ideas and opinions in a way which contributes to personal and social
development.
Epistemology (Higher)
In this Unit candidates study specific philosophical issues in the area of Epistemology.
They also study the positions of either René Descartes or David Hume. The Unit is
divided into two Sections and a brief overview of each Section appears below:
Section 1:
There is no choice of options in this Section of the Unit and candidates must study
all mandatory content.
Candidates investigate three questions which are relevant in the area of epistemology.
The three questions are:
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•
•
Why are knowledge claims a problem in philosophy?
What is knowledge?
Can knowledge claims be justified?
Section 2:
In this Section of the Unit there is a choice of option to be studied.
Candidates investigate either a specific rationalist or a specific empiricist epistemological
position. The options are:
•
Option A: Descartes’ Rationalism
or
•
Option B: Hume’s Empiricism.
Candidates must study all mandatory content in relation to their chosen option.
The positions adopted by each philosopher are based on reasoning and assumptions
which can only properly be understood by examining the writings of the relevant
philosopher. Candidates must therefore investigate the chosen position by studying key
extracts from the writings of that philosopher. The key extracts are prescribed.
A detailed outline of all mandatory content for each Section, including the key extracts for
each option in Section Two, can be found in the Appendix at the end of the Unit
Specification.
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Statement of Standards: Unit specification
This Unit is a mandatory Unit of the Higher Philosophy Course, but it can also be taken as
a free-standing Unit.
This Unit offers progression for candidates who have studied the Intermediate 2
Philosophy Course or Units. It is also suitable as a Higher level introduction for those who
have no background in the subject. The issues studied in this Unit underlie many
questions of both philosophical and general human interest such as ‘Can we know what
other people are thinking and feeling?’, ‘Can we know about things that we haven’t
experienced?’ and ‘Can we be certain that the world will continue to work in the way it
does now?’.
Candidates develop the knowledge and skills necessary to understand and investigate
specific philosophical issues in the area of epistemology. They investigate three specific
questions — ‘Why are knowledge claims a problem in philosophy?’, ‘What is knowledge?’
and ‘Can knowledge claims be justified?’ — and study specific extracts from the writings
of either René Descartes or David Hume.
Specific philosophical questions, issues, positions and extracts are studied in this Unit but
the critical thinking skills developed are relevant in a wide variety of contexts. These skills
prepare candidates for the study of Philosophy at Advanced Higher or in courses at
further education colleges or higher education institutions. Candidates will also be
prepared for the study of any other subject which requires the critical analysis and
evaluation of complex or abstract ideas. In addition, candidates will have demonstrated
the skills necessary for entry into any field of employment where the ability to analyse
issues and arguments, and evaluate complex or abstract ideas, is required.
Candidates completing this course may progress to:
•
•
Advanced Higher Philosophy or Advanced Higher Religious, Moral and Philosophical
Studies.
Further or Higher Education Courses which include the study of philosophy or require
the ability to reason in a critical manner.
Outcomes
1. Demonstrate an understanding of philosophical issues in the area of epistemology.
2. Critically analyse a standard philosophical position in the area of epistemology.
3. Critically evaluate a standard philosophical position in the area of epistemology.
Outcome 1
Demonstrate an understanding of philosophical issues in the area of epistemology.
Performance Criteria
(a) Describe the tripartite theory of knowledge.
(b) Describe specific philosophical problems associated with this theory.
(c) Describe the key philosophical positions of scepticism, rationalism and empiricism.
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Outcome 2
Critically analyse a standard philosophical position in the area of epistemology.
Performance Criteria
(a) Describe the account of knowledge given by one specific philosopher.
(b) Explain the reasoning and assumptions on which this account is based.
(c) Cite specific extracts from the writings of this philosopher in support of the
explanation.
Outcome 3
Critically evaluate a standard philosophical position in the area of epistemology.
Performance Criteria
(a) Explain the strengths and weaknesses of the account of knowledge given by one
specific philosopher.
(b) Present a conclusion on the persuasiveness of this account of knowledge.
(c) State reasons in support of this conclusion which are based on evidence and sources
previously discussed.
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Tutor Support Section
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1. Teaching Outline
1.1 Time Allocation
Centres vary in the amount of teaching time available to deliver the course. It is
recommended that teachers/lecturers begin by allocating roughly equal time to each
topic within the notionally allocated hours for the unit, and then adjust these times
depending on how the first year of delivery goes. Additional time should also be set aside
for formal assessment procedures. Assuming the recommended 40 hours are available
this could be allocated as follows:
Introduction to Epistemology
René Descartes
David Hume
Assessment/Reassessment
4 hours
15 hours
15 hours
6 hours
Total
40 hours
It is also recommended that teachers/lecturers deliver the topics in the order in which they
appear on the specification.
1.2 Delivery Outline
There are many possible ways to divide up the material and approach the different
theories. This will depend to a large extent on the number and duration of available
timeslots. One sequence of delivery might be the outline given below:
Introduction to Epistemology
• Plato and the Tripartite Theory of Knowledge
• Problems with Justified True Beliefs
• The Differences Between Scepticism, Rationalism and Empiricism
René Descartes
• Method of Doubt – importance of Descartes – historical context.
• Descartes’ Project and Method – ‘Meditations’, impact of ‘Cartesian doubt’, categories
of beliefs.
• Trusting Your Senses? – sensory perception, conflicting and inconsistent evidence,
optical illusions.
• The Dreaming Argument – the dream hypothesis, reality and the dream state, a priori
and a posteriori beliefs.
• The Role of God – the demon hypothesis, virtual reality, causal adequacy principle,
clear and distinct rule, trademark argument.
• Critical review and summary.
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David Hume
• Historical Context.
• The Egocentric Predicament.
• Impressions and Ideas.
• Impressions and Ideas II.
• Simple and Complex Ideas.
• No Innate Ideas!
• The Missing Shade of Blue.
• Hume’s Fork.
• Habits of Thinking.
• The Problem of Induction.
• Critical Evaluation of Hume.
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2. Learning and Teaching Approaches
There is an extensive list of learning and teaching approaches in the Course Specification
and further guidance in the Unit Specification. Please refer to these documents before
planning your classes.
As with all subjects, philosophy benefits from a range of pedagogical approaches.
Lectures or teacher-led exposition is invaluable for introducing difficult concepts or filling
in historical background in philosophy. However, the discursive aspect of this academic
discipline is best developed with group activities: a selection of which are included in this
pack. Teachers/lecturers should also emphasise the key skills in group discussion and
make sure that they are fruitful activities rather than directionless arguments. Students
should be made aware that during group activities they should:
•
•
•
•
listen to what others have to say
articulate their own thoughts as clearly as possible
give others an opportunity to respond; make explicit which others in their group they
agree or disagree with
identify the underlying reason for any disagreement.
Reading, writing and comprehension skills are also of paramount importance and a
selection of set chapters with questions have been provided to train students into getting
the most from secondary sources. These are best used as individual activities. Although
students should be encouraged to give succinct but informative responses to these
questions they should equally be steered away from one word answers and lazy or poor
presentation.
Finally, like any other discipline, philosophy has a technical vocabulary, and students
should be urged from the outset to take a note of new terms and phrases and make full
use of philosophical dictionaries and encyclopaedias to expand their vocabulary.
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3. Guide to Resources
3.1 Books
Bibliography
Arrington, R. (Ed.) (2003) The World’s Great Philosophers. Blackwell.
Broadie, A. (Ed.) (1997)The Scottish Enlightenment An Anthology. Canongate Classics.
Conee, E. and Feldman, R. (2004) Making Sense of Scepticism – in Evidentialism.
Oxford University Press.
Curley, E.M. (1978) Descartes Against the Skeptics. Harvard University Press.
Cottingham, J.G. (1986) Descartes. Blackwell.
Cottingham, J.G. (Ed.) (1992) The Cambridge Companion to Descartes. Cambridge
University Press.
Daiches, D., Jones, P. and Jones J. (1986) A Hotbed of Genius: The Scottish
Enlightenment: 1730-1790. Edinburgh University Press.
Dancy, J. and Sosa, E. (Eds.) (1993) A Companion to Epistemology. Blackwell.
Descartes, R. (Trans. by John Cottingham) (1986) Meditations on First Philosophy With
selections from the Objections and Replies. Cambridge University Press.
Falzon, C. (2002) Philosophy Goes to the Movies. Routledge.
Fumerton, R. (2006) Epistemology. Blackwell.
Gettier, E. ‘Is Justified True Belief Knowledge?’ in Analysis 23, pp. 121-3.
Grayling, A.C. (2005) Descartes: The Life of Rene Descartes and Its Place in His Times.
Simon and Schuster.
Matson, Wallace I. (1999) A New History of Philosophy Volume II: From Descartes to
Rawls. Wadsworth.
McNabb, D. (1966) David Hume (2nd Ed.). Blackwell.
Monk, R. and Raphael, F. (2000)The Great Philosophers. Phoenix.
Noonan, H. W. (1999) Hume on Knowledge. Routledge.
Norton, D. F. (Ed.) (1994)The Cambridge Companion to Hume Cambridge University
Press.
Pears, D. (1990) Hume’s System. Oxford University Press.
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Popkin, R. H. and Stroll, A. (1998) Philosophy – Made Simple (3rd Ed.) Reed Educational.
Roderick, G. (1995) The Great Infidel: A life of David Hume. John Donald Publishers.
Russell, B. (1961) History of Western Philosophy. Routledge.
Stroud, B. (1977) Hume. Routledge.
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Student Support Section
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Introduction to Epistemology
What is Philosophy?
In order to start thinking about Epistemology it might make sense to remember what
philosophy itself is about. So let’s begin by thinking about this question: What is
philosophy?
Is it about the ‘love of wisdom’ (which is what the word actually means!) or is it ‘thinking
about thinking’ or ‘a search for ‘the truth’?
Some philosophers have said that everyone is a philosopher. Do you think that is right?
Or are there things that philosophers do, ways in which they argue and question things,
which are different from how non-philosophers do these things?
Activity 1
If there are no answers in Philosophy but just more questions, does this mean it is worth
doing at all?
Activity 2
The English philosopher Bertrand Russell said that philosophy is ‘the no-man’s land
between science and theology’.
What do you think he meant by that?
Activity 3
The German philosopher Nietzsche thought that a philosopher was ‘a terrible explosive in
the presence of which everything is in danger’!
What do you think that view suggests?
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What is Epistemology?
Epistemology is a particular branch or part of philosophy concerned with asking questions
about the nature of knowledge. In epistemology we are interested in trying to work out
what knowledge is, how we know things, and whether or not – as a result of possible
answers to these questions – it is possible to be sure or to be certain about what we
know. These are very important questions because all the things that we think of as ‘true’
might be affected by the answers. Some things that we think are certain and true might
turn out to be false, some things we think are sure and certain might end up being unsure
and uncertain, so this part of Philosophy is clearly very important.
Whether or not we think that philosophy is just about questions – not answers – it is
certainly the case that some philosophers tried to work out arguments that provided
definite and clear answers to the big questions. In the area of Epistemology, philosophers
like Plato in ancient Greece and Descartes in France tried to provide us with definite
answers about the nature of knowledge. We will be looking at some of the things these
philosophers had to say.
Activity 4
List three things you know for certain.
Why do you think these are good examples of certain knowledge?
Can you think of an example of something that we previously thought was true but which
we now know is false?
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Plato
The Ancient Greek philosophers were interested in questions about the nature of things,
about how the world came to be and how it worked.
For many of them it seemed clear that the world around us is always changing and
nothing stands still, so from that they came up with the view that there could not be any
certainty about things.
Some, like Plato did not agree and argued that we could not just rely upon how things
looked on the surface, we had to think, we had to reason about the world and that when
we did we could identify things that did not change and remained true.
However surely we know about the world through being able to see, hear, and feel, in
other words we know about things because of the senses. Is it not the case that the
senses give us knowledge of the world about us? Plato was not impressed by this idea. It
is too easy for the senses to be misled, for us to get it wrong in some way.
For example if we put a pencil into a glass of water, it might look as if the pencil was bent
when in fact we know it’s straight. There are many other examples of problems of this
kind, where the evidence based on the senses is just wrong – and we know it’s wrong.
For this reason the senses, according to Plato are just not enough they do not provide us
with ‘knowledge’ of the world, because they can give us false information.
Is knowledge then just about what we can work out in our minds? Is it just reason at
work? After all, we ‘know’ the pencil does not bend when it goes into water – and we
‘know’ that just because of our ability to reason – to work things out. But our reason too
can be wrong, so Plato was not satisfied by this argument either. Knowledge had to be
more than just the things told to us about the world by our senses, and more than just
what we can work out by reason.
Activity 5
Give three examples things we can know through sense experience.
Give three examples of things we can discover by pure reason.
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The Tripartite Theory of Knowledge.
Knowledge, for Plato, has to be about what is true – so he makes a distinction between
what we just believe – things that may or may not be true – and knowledge which is what
we know to be true. In order to know something is true we have to have some kind of
justification for our belief. That gives us two conditions for ‘knowledge’.
1. We have to believe it.
2. We have to have some kind of justification for believing it.
So it’s not enough just to say that something is true just because ‘I know it’s true!’ – we
have to have some kind of evidence or argument that gives a justification for our belief.
But there is one other condition that has to apply as well – we have to be right – what we
believe and what we think we have justification for – does also have to be true. That
gives us the third part of the ‘Tripartite Theory of Knowledge’ – for something to be
‘knowledge’ and not just our belief – it has to be ‘Justified, true belief’.
Let’s take an example to demonstrate this point. Imagine the following scenario:
‘The Prime Minister says that crime rates will go down next year.’
Is this a piece of knowledge according to the tripartite theory? According to the tripartite
theory, the Prime Minister can only be said to have knowledge if:
He believes that crime rates will go down (ie. he isn’t just lying to us).
He can justify his belief (eg. by referring to recent crime figures suggesting a downward
trend).
It is actually true that crime rates will go down. (He can’t be said to have had knowledge
if it turns out that crime rates are going up.)
Activity 6
According to the tripartite theory, what three conditions must be met for the statement
‘Scotland will win the next world cup’ to count as knowledge?
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Problems with Justified True Belief
On the face of it the Tripartite theory looks quite good. Plato had insisted that in order to
qualify as knowledge and not just as some kind of belief, we had to have satisfied the
three conditions: we had to believe it, we had to have justification for what we believed,
and it had to be actually true. However there are a number of examples where these
conditions are not easily met.
Here is an example:
Jim is on holiday in America. When driving in the West he passes by towns that look like
towns he has seen in films about the ‘Wild West’ and he thinks he is seeing genuine
places that the films are based upon. In fact what he seeing in fake fronts raised by
enterprising tourist companies to give a completely false impression, but as it happens as
he drives along he also goes through a genuine ‘frontier’ town with genuine buildings. In
this instance he is right to think of the town as a genuine ‘Wild West’ location. But is this
justified, true belief?
There seems to be a problem with the evidence, the sensory-based information we have
about the world that in effect undermines what we consider to be knowledge.
In fact we can take that problem a step further. Sometimes when people are ill in one way
or another they can find it difficult to understand the difference between what they thought
or even dreamt happened, and what actually happened. What if we are all really in that
position, what if everything we see, feel, hear and so on, is nothing more than a
complicated form of dream? If we can be deceived by the senses, maybe we can also be
deceived about what is real and what is not real by the ways in which our minds work?
In the film The Matrix the central character discovers that his ‘reality’ is in fact an
elaborate programme run in a computer system and that the reality is that his body is
being kept in a state of sleep by machines while the illusion of reality is fed into his brain.
For most people subject to this process there is no escape, no way that they can tell that
they are part of a computer program. What if that is true and the world about us is all a
dream?
The Gettier Problem
In the 1960s a philosopher called Edmund Gettier came up with some questions and
examples that really undermined the tripartite theory.
Here is a Gettier-type example:
John is the supporter of a particular football team. His team are playing in an important
final and he wants to know the results. He calls up a friend to ask him how things went.
His friend only saw part of the match, and is sure that John’s team lost but decides as a
joke to tell him his team won. What John’s friend does not know is that after he stopped
watching the match, John’s team went on to win. So John believes something that is in
fact true, it was justified by his friend’s account, and it turned out to be in fact true.
But does this really count as knowledge when in fact it was an accident that his belief was
true? Does this actually mean that you can just be lucky sometimes about what is truly
knowledge and meets the terms of the tripartite theory, or is it the case that the theory is
just wrong? The worrying thing about the Gettier example is that every condition of the
tripartite theory has been met and yet we still wouldn’t want to count it as knowledge.
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Activity 7
Consider the following scenario. Do you think that it counts as an example of
knowledge? If so, state how it satisfies the tripartite conditions. If not, explain why not.
The Lucky Rabbit’s Foot
Every time Sandra puts on a bet she rubs her lucky rabbit’s foot which is on a key ring in
her pocket. Each time she does this the horse she bets on wins. One day she loses her
keys and doesn’t find them in time to rub the rabbit foot before placing her bet. The horse
loses and she loses her bet and says to herself, ‘I knew that horse was going to lose! I
didn’t get a chance to rub my lucky rabbit’s foot.’
Activity 8
Consider the following scenario. Do you think that it counts as an example of
knowledge? If so, state how it satisfies the tripartite conditions. If not, explain why not.
The Hesitant Student
Billy is sitting daydreaming in class. They are doing Maths and he hates Maths.
Suddenly his teacher asks, ‘Billy, what is the square root of nine?’ Suddenly woken out of
his daydream Billy gathers himself and answers, ‘Er, three?’
‘Well done Billy’, says his teacher.
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Scepticism, Rationalism and Empiricism
If someone has philosophical doubt about the reliability of evidence based on our senses,
they are being a ‘sceptic’. If knowledge requires justification and requires to be true – we
are in trouble when we come up against a sceptic, because they will tell us that we don’t
know what is true, because everything we sense could be false.
We do need to be clear that there is a difference between ordinary doubt about
something and being a philosophical sceptic. For example during a football match there
is a dispute over a goal: your friend is convinced the ball went over the line, but you are in
doubt. During the reply the camera focuses close up on the line and in fact it was not a
goal. Does the fact that you doubted the goal make you a sceptic? No.
Where it is possible to clarify a doubt, to resolve it by use of evidence, then the grounds
of the doubt are not the issue. Sceptics have issues with the nature of evidence, they are
not satisfied that doubts can be resolved by evidence, because all evidence can be
doubted.
For example, once Neo in The Matrix knows that the world he lives in is false, no amount
of evidence presented to him in that world is going to convince him that it is true. The
sceptic is in a similar position: the very evidence that people might call upon to ‘prove’
that it is possible to have reliable knowledge of the world is based upon the view that it is
possible to have reliable knowledge!
Some philosophers believe that it is the case that real, true knowledge is based on the
experience we have of the world, that is to say that our senses, tricky and fallible though
they are, do tell us about what is going on outside of our own minds. These philosophers
are described as empiricists. Empirical knowledge is knowledge based on experience
and this is also described as a posteriori knowledge, that is to say knowledge that
comes after experience.
Some philosophers don’t agree with that view, and think that even though we do learn
about the world through our senses, more importantly we reason, and it is the operation
of our reason that gives us the real truth about the world. These philosophers are known
as rationalists because they think that reason is more important than experience. This is
also described as a priori knowledge – that is, knowledge that comes before experience.
Sceptics think that both these positions are in trouble, because we can’t rely on the
senses, but we can’t rely upon reason either!
Activity 9
What is the Difference between Scepticism, Empiricism and Rationalism?
paragraph outlining your answer.
Write a
Activity 10
Think about the following statements. Can they be justified: Yes or no?
If so how: by reason or by experience?
Australia has poisonous spiders.
The Arctic is just ice floating on water.
Men travelled to the moon in a spacecraft, landed and walked on the surface.
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There are aliens in spacecraft watching our every move.
There is an invisible force called ‘gravity’ that pulls everything down to the ground.
In the past people thought that the world was flat instead of round.
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René Descartes
The Method of Doubt
Why is Descartes Important?
René Descartes (pronounced ‘day-cart’) was born in 1596, just south of Tours, in the
Loire region of France. Descartes is often referred to as ‘the father of modern
philosophy’. This may seem a strange description considering he was born in the 16th
century!
Descartes was critical of the philosophy and science of his day. It is important to know
that in the past, what we now know as ‘the sciences’ were part of the study of philosophy.
Philosophy had remained largely unchanged for two thousand years, being based on the
work of the ancient Greek philosopher Aristotle, who lived in the 4th century BC.
Descartes was not convinced by the arguments from Aristotle however, and because he
broke away from many of the ideas and arguments that were based on Aristotle’s work he
really began the arguments that came to be really important for modern philosophy.
Descartes was educated, from the ages of 10 to 18, at the Jesuit College of La Flèche.
While he was there he began to think that, with the exception of mathematics, most of the
subjects which he was being taught were too uncertain to count as genuine knowledge.
Descartes was to go on to be a brilliant mathematician for example he invented what we
now call ‘Cartesian co-ordinates’.
Mathematics, particularly the new mathematics he learned at La Flèche did seem to him
to be better organised and more carefully thought out, than much of what then was
accepted as philosophy. Philosophy, he began to think, needed to be brought up to date
and put onto a proper foundation.
Descartes left La Flèche in 1614, and went first to study Law, and then to join the Dutch
army as an unpaid gentleman soldier (he wanted to travel, and to learn more about ‘the
great book of the world’). In 1619, Descartes had a formative experience. While sleeping
in what he later described as ‘a stove-heated room’, he had three vivid dreams. These
dreams gave him a vision of all knowledge linked together into one great system of
thought.
Descartes’ ambition was now established: he would set out to achieve this unification of
all knowledge. What would a ‘unification of all knowledge’ involve? Descartes aimed for
knowledge of ‘life, the universe and everything’! This is what having ‘all knowledge’ will
involve. To explain the ‘unity’ part of his ambition, Descartes compared knowledge to a
tree. There might be different branches of knowledge but they would all be part of the one
tree, and it might be that some areas of knowledge would be like the roots, the support of
everything else, some might be like leaves, feeding the tree but it would still be the case
that all areas of knowledge would belong to the same thing. In fact he thought that areas
of philosophy would be in effect the roots upon which everything else would depend.
Activity 1
Read the first two paragraphs of Descartes’ Meditation 1.
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Support Notes: Philosophy – Epistemology Higher
Descartes’ Project
In the opening sentence of the Meditations, Descartes sets out his project: his reason for
writing the book, and what he hopes to achieve:
‘It is now some years since I detected how many were the false beliefs that I had from my
earliest youth admitted as true, and how doubtful was everything I had since constructed
on this basis; and from that time I was convinced that I must once and for all seriously
undertake to rid myself of all the opinions which I had formerly accepted, and commence
to build anew from the foundation, if I wanted to establish any firm and permanent
structure in the sciences’.
In other words Descartes started this work with the recognition that like many of us, he
had believed things that later were shown to be false. And more, that the basis for
believing many things he held to be true, turned out to be pretty poor. So, in the
Meditations, Descartes sets out to sort out himself. This is one of the unique things about
his way of working; it is very personal and direct. The Meditations he writes about are his
own thoughts about his own beliefs.
What he also makes clear in this opening statement is that he had beliefs that were built
on other beliefs and that when he found that these basic beliefs were false, then
everything he had built upon them was also undermined and in doubt. In other words he
is making it clear that he needs to think about the underlying beliefs the fundamental or
foundational ideas that serve as the start of everything else. If he can sort out these
ideas, then he will have something to build on.
Another way of thinking about this is to go back to the idea of the tree. If the leaves and
branches of the tree represent different areas of science, we have to be really certain that
the roots of this tree which support everything else, are good and solid. If they are not –
then no matter how good the branches are everything is going to come crashing down!
So how can we make sure that the foundations of things are in good order? The only
answer, according to Descartes, is to start by putting to one side everything that can be
doubted, in order to see what is left. In maths what you do is you establish what is
definitely true and once you have that then you can build on it. Descartes wants to do the
same thing with philosophy. Anyway, philosophy he thought had been carried out in a
manner similar to someone walking about the streets with their eyes on the ground in the
hope that they would come across something valuable. There was no system, no order to
it and if little nuggets of gold had been found, it had been more or less accidental. Now it
was time to put the whole discipline onto a better basis.
Activity 2
1. Write down three beliefs you consider to be true.
2. What ‘evidence’ do you have that what you believe to be true, is actually true?
3. Can you list the kinds of evidence you base your beliefs on?
4. Do you think that in a discipline such as philosophy you should accept the arguments
of people from the past just because they are regarded as experts or ‘authorities’?
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Support Notes: Philosophy – Epistemology Higher
Descartes’ Method
‘Suppose [a person] had a basket full of apples and, being worried that some of the
apples were rotten, wanted to take out the rotten ones to prevent the rot spreading. How
would he proceed? Would he not begin by tipping the whole lot out of the basket? And
would not the next step be to cast his eye over each apple in turn, and pick up and put
back in the basket only those he saw to be sound, leaving the others?’
(Replies 7, AT 7:481)
Descartes is setting out to sort philosophy out, to put it on a proper and better-organised
basis. And to do this he is going to begin by ‘tipping the whole lot out’ in other words he is
going to put to one side everything that can be doubted.
This idea, known as ‘Cartesian Doubt’ is radical stuff. People who doubt everything are
‘sceptics’ as we have seen, and it is notoriously difficult to persuade those who have
taken a sceptical view, that anything is certain and true. On the face of it by using
‘Cartesian Doubt’ it seems that Descartes is becoming a sceptic. But in fact he has an
entirely different purpose. Descartes wants to show that the sceptics are wrong, but to do
that he has to deal with doubt he has to show that it is possible to arrive at something that
cannot be doubted. Remember that Descartes’ project was to produce ‘a firm and
permanent structure in the sciences’. Far from being a sceptic Descartes wants to answer
the sceptics difficulties once and for all.
How can he do this? He has to be a greater doubter than any sceptic until he arrives at a
truth that cannot be doubted. To begin with then Descartes has to go through all his
beliefs and check to see (like the apples in the barrel) which ones can be doubted and
which ones can be kept. The Meditations are an account of this journey with each one
reading as if it was written on a separate day during this exercise in self-examination.
There are six mediations, one for each day of his journey.
In Meditation 1 he indicates that he is ready to start this process, but that ‘it is not
necessary that I should show that all of these beliefs which I have accumulated over the
course of my life are false, I shall perhaps never arrive at this end’. Instead maybe what
he can do is doubt groups of ideas, things that are based on common grounds, like the
senses, for example. Descartes has to be really careful here; after all, he can’t allow
himself to get into the position of passing something as doubt-free, which later on he finds
can be doubted.
‘… reason already persuades me that I ought no less carefully to withhold my assent from
matters which are not entirely certain and indubitable than from those which appear to me
manifestly to be false …’
To ‘withhold my assent’ means ‘to refuse to accept as true’. ‘Indubitable’ means ‘not able
to be doubted’. He has to be really sure that whatever is left at the end of this process is
certain beyond any possibility of doubt. So even things that might be true, or things that
are probably true but about which there still can be some little doubt, have to be put to
one side with the rest. So to get this task done Descartes needs to be careful and exact,
but he also needs to arrive at ways of doing this without going through every single notion
or idea.
To say a belief is ‘manifestly false’ is to say that its falsity is obvious and we don’t need to
think about it to see that it is false. The claim that ‘there are some circular triangles’ is
manifestly false: if I believe that it is possible for some object to be both circular and
triangular at the same time, then my belief is just absurd.
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Support Notes: Philosophy – Epistemology Higher
So Descartes has identified two categories of belief:
1. Beliefs which are not entirely certain and indubitable.
2. Beliefs which are manifestly false.
In other words:
Uncertain beliefs; and
False beliefs.
Now remember what Descartes has just suggested, that:
‘I ought no less carefully to withhold my assent from matters which are not entirely certain
and indubitable than from those which appear to me manifestly to be false’. This is how
rigour the second of our requirements listed above is going to be achieved. For any belief
which he has, Descartes is going to ask the question:
Is this an uncertain belief?
If the answer is ‘yes’, however slight the doubt, Descartes will, as he has just put it,
‘withhold his assent’. In other words, he will not allow the belief in question to be
accepted, it will be put to one side like other things that can be doubted.
We have gone through a kind of careful, precise argument that was designed to make
sure that Descartes never accepted anything as true without being absolutely certain that
it could not be doubted. Earlier we thought about making up a list of things and trying to
see if there was anything about them that they had in common. One way of dealing with
a number of different ideas we have about the world is to think about what they are based
on. For example, much of what we know about what is going on, we get from the TV. Is it
possible to doubt what is said by newsreaders and announcers on TV?
Thinking about that what we can see is that if the basis of what we know is doubtful, if for
example, we think that the things we read in newspapers are not always true, then we will
be inclined to doubt anything we read there. In a similar fashion, Descartes comes to the
view that if the foundations, the basis for different ideas about the world can be
questioned and doubted, then all the ideas that rest on those foundations can also be
doubted.
Remember, Descartes is not a sceptic, he is not committing himself to the view that lots
of things are doubtful; at this stage in the Meditations he is just putting to one side
everything that could be doubted. And since ‘Owing to the fact that the destruction of the
foundations … brings with it the downfall of the rest of the edifice, I shall only in the first
place attack those principles upon which all my former opinions rested’.
Think about the best way to demolish a building, such as a block of flats. A very inefficient
way to knock down the building would be to take a sledgehammer and knock the building
down, brick by brick. How it is actually done is just as Descartes suggests: demolition
experts will put dynamite around the foundations of the building; once these have been
destroyed, the whole building collapses – and a lot of time is saved. Using dynamite on
the foundations is a shortcut to the job of demolition.
Descartes takes beliefs to be like clusters of tall buildings – each set of beliefs resting on
its own foundation. So his shortcut will be like the demolition man’s shortcut. What he will
do is attack ‘the principles upon which my former beliefs rested’: the foundations.
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Support Notes: Philosophy – Epistemology Higher
Descartes’ Mistrust of the Senses
‘All that up to the present time I have accepted as most true and certain I have learned
either from the senses or through the senses …’ (Meditation 1)
This seems to make sense – most of what we know with confidence we have learned
through our senses. If we know that the sun comes up each day, we know it because we
have seen it, felt its heat, heard people talk about it, and for that matter read about it and
discussed it in school and with other people. Most of the really ordinary day-to-day facts
we know come to us through the senses. And for the most part we tend to have the
greatest confidence about things we know that we have seen for ourselves, or felt or
heard directly. The best way of knowing something for sure is to be there yourself,
experiencing it directly.
In fact the idea of ‘justified true belief’ which we have discussed works well with things
that we have directly experienced. If we have seen or felt the sun’s heat then we can
clearly have justified true belief that the sun is there and is warm. What we are also
accepting then is the view that what we experience directly gives us reliable information –
the sense themselves can be relied upon. Or to put it another way the information we get
from the operation of the senses is a reliable foundation for knowledge.
Is that correct? Are the senses really reliable? We have mentioned already that the
senses can be fooled. In The Matrix the hero Neo, believed that the sun was coming up
every day – but it wasn’t. At least he was not seeing a real sun in a real sky. We have
mentioned how a pencil put into a glass of water appears to bend, when it in fact does
not. There are many such ways to fool the operation of the senses. Quite often when
people witness an accident and are asked about it later, they give completely different
accounts of what took place not because they are lying, but because they perceive the
event differently. That is their memory of how their senses recorded the event differs from
one to the other.
Activity 3
Make a list of 10 ways in which your senses fool you. Remember, you have five senses
and all of them can fool you in different ways.
So can we rely upon the senses and does Descartes think that beliefs based upon the
senses cannot be doubted? Descartes will give three reasons for thinking that the answer
is ‘no’. His first reason involves problems such as optical illusions. Towards the end of
the text, in Meditation 6, Descartes provides examples of such deceptions:
‘… I from time to time observed that that those towers which from afar appeared to me to
be round, more closely observed seemed square, and that colossal statues raised on the
summit of these towers, appeared as quite tiny statues when viewed from the bottom …’
The senses, in other words, will, on occasion, give us conflicting evidence:
a) The tower is round.
b) The tower is square.
c) The statue is large.
d) The statue is small.
It is not possible for both (a) and (b) to be true; the two statements are inconsistent – as
are (c) and (d).
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Support Notes: Philosophy – Epistemology Higher
When we have inconsistency, when we can’t rely upon the senses to give us good
information all the time, we have to accept that anything based on the evidence of the
senses can be doubted. And that means that Descartes has to put to one side all those
beliefs and ideas that are based on the operation of the senses.
However – this might not apply to absolutely everything! After all, can we doubt that we
are sitting reading this, can we doubt where we are and what we are doing right now?
Surely these things cannot be doubted, in fact Descartes admits this: ‘The fact that I am
here, seated by the fire, attired in a dressing gown, having this paper in my hands …’.
This kind of knowledge does not appear to be open to possible doubt; is it?
Descartes considers two possible reasons for taking this knowledge to be open to
possible doubt. Firstly, there is the case of the insane. They are also liable to believe
that: ‘… they are clothed in purple when really they are without covering, or who imagine
that they have an earthenware head …’
Here, what seems to be reliable sense-based experience is not reliable at all. Here the
naked madman will believe that his experience of purple clothing is being caused by
purple clothing which he is wearing, but he is in error. What is responsible for this
experience (according to the medical view of Descartes’ time) is ‘the violent vapours of
black bile’. All right, but here we are talking about what Descartes’ is happy to accept or
reject: not what a madman will do!
Descartes is confident that he is not mad (‘I should not be any the less insane were I to
follow examples so extravagant’). It seems that the beliefs earlier established – that I am
here, seated by the fire, attired in a dressing gown, having this paper in my hands, etc. –
are not beliefs which fall into the category of doubtful beliefs, so that I need put them
aside with other things that might be taken from sensory evidence. So it looks like some
of those things that are based on the senses have to be doubted, and some can be kept.
But Descartes has an even more powerful argument up his dressing gown sleeve!
Activity 4
Read the rest of Meditation 1, from the beginning of the third paragraph to the end.
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Support Notes: Philosophy – Epistemology Higher
The Dreaming Argument
Descartes has identified a set of beliefs, ‘that I am here, seated by the fire, attired in a
dressing gown, having this paper in my hands’, etc., which, it seems, cannot be doubted.
If these beliefs cannot be doubted, then they pass the very strict test of the method of
doubt, Cartesian Doubt that we referred to before.
According to Descartes rules, the terms he established for himself early on in the
Meditations, he must put to one side anything that it is possible to doubt even if only
slightly. Taking Descartes own terms and applying them to the sensory information about
where we are and what we are doing, we have to ask, are any optical or other kinds of
illusion involved? Are we mentally unbalanced to the extent that we don’t know where we
are or what we are doing?
If the answer to both these questions is no then it seems that we might be able to rely
upon this evidence. Illusions like optical illusions tend to be quite limited in their effect, it
might be more difficult to be certain about questions of sanity which can be more
complicated, but given that we are sure about our sanity for the moment does that leave
us any room for doubt?
‘At the same time I must remember that I am a man, and that consequently I am in the
habit of sleeping, and in my dreams representing to myself the same things or sometimes
even less probable things, than do those who are insane in their waking moments. How
often has it happened to me that in the night I dreamt that I found myself in this particular
place, that I was dressed and seated near the fire, whilst in reality I was lying undressed
in bed! At this moment it does indeed seem to me that it is with eyes awake that I am
looking at this paper; that this head which I move is not asleep, that it is deliberately and
of set purpose that I extend my hand and perceive it; what happens in sleep does not
appear so clear nor so distinct as does all this. But in thinking over this I remind myself
that on many occasions I have in sleep been deceived by similar illusions, and in dwelling
carefully on this reflection I see so manifestly that there are no certain indications by
which we may clearly distinguish wakefulness from sleep that I am lost in astonishment.
And my astonishment is such that it is almost capable of persuading me that I now
dream.’ (Descartes, Meditation 1)
Dreaming is something that affects all human beings – ‘I am a man, and … consequently
I am in the habit of sleeping, and in my dreams representing to myself the same things …
[as] those who are insane in their waking moments.’
Descartes’ reference here to ‘representing to myself …’ requires clarification. We need to
think of two kinds of experience:
1. Experiences caused by physical objects.
2. Experiences caused by my dreaming.
In the case of optical illusions, I may recognise the possibility that my senses are
deceiving me, and can check to see whether this is in fact the case. But notice how
Descartes suggests that ‘there are no certain indications by which we may clearly
distinguish wakefulness from sleep’. This time, I have no way of checking to see whether
my experiences are being caused by physical objects, or caused by my dreaming.
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Support Notes: Philosophy – Epistemology Higher
Take a statement which is certainly true: It seems to me that there is a piece of paper in
front of me. How do I know whether this is an experience which is being caused by a
physical object – a piece of paper – or an experience which is being caused by my
dreaming? It certainly feels like an experience which is being caused by a piece of
paper. But note what Descartes says about this: ‘on many occasions I have in sleep been
deceived by similar illusions’.
This leads Descartes to the following conclusion:
I cannot be certain that I am not now dreaming.
This is sometimes referred to as ‘the Dream Hypothesis’. If it is true, then I can never
be certain that a particular experience is being caused by physical objects, rather than
being caused by my dreaming. This in turn means that I can never trust my senses: the
objects which they seem to be giving me experience of might not exist at all.
If, as Descartes has earlier suggested, the beliefs which I have until now accepted as
most true and certain are based upon the belief that the senses are reliable, then the
Dream Argument would appear to make all such beliefs uncertain. If I cannot be certain
that I am not now dreaming, and if this is always the case, then I cannot ever be certain
that what seems to be the evidence from the senses is actually real and not just the
product of my dreams. So that is that, nothing that could be the result of a dream of some
kind can be accepted and as a result nothing that is based on the operation of the senses
can be trusted.
Now you may be thinking that you do know with confidence the difference between
dreaming and reality. But remember that Descartes is only concerned at this stage with
establishing whether or not it is possible to doubt something, it might be for example that
sometimes when you are dreaming you can’t tell that it is a dream, that is something you
can only know when you are not dreaming. But can you prove that what you are
experiencing now is not a dream?
Activity 5
How do you tell the difference between dreams and reality?
Are there any features of dreams that convince you that you are dreaming? In what ways
might you prove that you are not dreaming right now?
Make a list of the main ways in which dreams differ from reality.
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Support Notes: Philosophy – Epistemology Higher
Limitations of the Dreaming Argument
If I cannot achieve a firm and permanent structure in the sciences by relying on the
senses, I may be able to do so by the use of reason. To arrive at knowledge via reason
is to arrive at knowledge just by thinking – without the use of the senses. Even if I have
never seen an example of a straight line, I know that a straight line is the shortest
distance between two points and I know this just by thinking about what it is for something
to be a straight line. This goes for all straight lines: all of them are the shortest distance
between two points.
This is an example of a priori belief. A belief is a priori if it is arrived at independently of
experience – just by thinking. By contrast an a posteriori belief is one that we come to
as a result of evidence we have experienced.
•
•
a posteriori belief – there is a rectangular computer screen in front of me
a priori belief – the internal angles of a rectangle add up to 360.
The Dream Argument does not affect this kind of belief. Even if I am dreaming, it still
remains the case that all straight lines are the shortest distance between two points.
Similarly, I may be dreaming that there is a rectangular computer screen in front of me –
but I am not dreaming that the four angles of a rectangle add up to 360°. Whether I am
dreaming or not that belief is surely true.
So grounds for doubting the reliability of the senses are not grounds for doubting the
reliability of reason. However Descartes has not finished, his Cartesian Doubt has one
more step to take. In order to take that step we need to turn to an area of belief that is
important, and was in Descartes time, very important.
Activity 6
Consider the following statements. Which are capable of being known a priori and which
are capable of being known a posteriori?
•
•
•
•
•
•
Lemons taste sour.
2 + 2 = 4.
Cats feel furry.
Child torture is wrong.
All men are mortal.
All bachelors are unmarried males.
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Support Notes: Philosophy – Epistemology Higher
The Evil Demon Hypothesis
To see how Descartes finds grounds for doubting the reliability of reason, we need to
consider God, as he is traditionally conceived by philosophers.
In Descartes time it was not unusual for thinkers in a variety of fields to discuss, and write
about God in a number of ways. In their way of thinking, God has three properties:
•
He is omnipotent (all powerful). There is nothing God cannot do.
•
God is omniscient (all knowing). He is never in doubt, never in ignorance and never
in error.
•
He is perfectly good.
One way of thinking about what Descartes does next is to imagine a being who had the
first two of these properties, but not the third. This being is omnipotent (so can tamper
with my thoughts), omniscient (so can read my mind at all times), but is evil rather than
perfectly good (so that he will not hesitate to deceive me). This is the ‘Demon’ or, in some
translations of Descartes’ book, the ‘Evil Genius’.
‘I shall then suppose, not that God who is supremely good and the fountain of truth, but
some Evil Genius not less powerful than deceitful, has employed his whole energies in
deceiving me …’
It is important to stress that Descartes does not believe that there is a demon who is
doing this. He believes that he cannot prove that such an individual does not exist. This
gives us the ‘Demon Hypothesis’:
•
I cannot be certain that there is no omnipotent and omniscient and evil being who is
bent on deceiving me.
Notice what the demon can do, if we take as our example a simple piece of reasoning:
I ask myself: what is the sum of 3 + 2?; The demon (employing his omniscience) is aware
that I am trying to work out this sum; He intervenes (using his omnipotence) to make me
arrive at the wrong result; and I get the answer 5 – which is wrong.
So I believe that 3 + 2 = 5, but that is because I trust my powers of reasoning. But if I
cannot be certain that there is no demon bent on deceiving me, then I cannot be certain
that reason is reliable, and so I cannot be certain that 3 + 2 really does = 5.
As before, the Method of Doubt now comes into play.
My belief that reason is reliable is put into doubt by the demon:
•
•
•
As a result of this, I must withhold my assent from my belief that reason is reliable.
As a result of this, all a priori beliefs are now open to possible doubt.
As a result of this, I must withhold my assent from all a priori beliefs.
The demon has another important to role to play in Descartes’ philosophy.
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Support Notes: Philosophy – Epistemology Higher
Before discussing the demon’s impact on the reliability of reason, Descartes asks the
question:
‘How do I know that He has not brought it to pass that there is no earth, no heaven, no
extended body, no magnitude, no place, and that nevertheless [I possess the perceptions
of all these things and that] they seem to me to exist just exactly as I now see them?’
What we have here is the introduction of a very radical form of scepticism. Scepticism is
the denial that knowledge is possible. The Dream Argument has led to a sceptical
conclusion: if I cannot be certain that I am not at this moment dreaming, then I cannot be
certain that the experience which I have of a coffee cup on my desk is being caused by a
coffee cup, and not being caused by a dream. In dreams we may have the experience of
visiting places that do not really exist, meeting people who do not really exist, etc. So the
Dream Argument leads to the conclusion that I cannot be certain that what I am
experiencing at this moment is really happening.
Activity 7
Why does Descartes need the demon argument?
What does the demon argument do that that the dreaming argument doesn’t in Descartes
Meditations?
Write a paragraph outlining your answer.
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Support Notes: Philosophy – Epistemology Higher
Demons and Virtual Reality
‘How do I know that He (the Demon) has not brought it to pass that there is no earth, no
heaven, no extended body, no magnitude, no place, and that nevertheless [I possess the
perceptions of all these things and that] they seem to me to exist just exactly as I now see
them?’
The above quotation from Descartes shows that the Demon Argument leads to a much
deeper level of scepticism. When I dream, I dream about cups and desks and buildings
and other physical objects. The dream takes these things from the real world, the world
outside my mind, and presents me with experiences of things which don’t actually exist,
but which are made up from representations of things which do exist (from real desks and
buildings and so on).
Now look again at the quotation from Descartes. The Demon Argument (which starts
from the claim that I cannot be certain that there is no demon) puts in doubt the claim that
there is a real world of physical objects at all. The demon could cause me to have
experiences of a world of physical objects existing in space and time, when there is no
such physical reality at all.
Descartes is trying to refute scepticism, he is trying to produce a ‘firm and permanent
structure in the sciences’. If he is going to be successful in this, he must prove that there
actually is a physical world in space and time and show that there is something to have a
science of. Once he has done that, then he can consider the other level of scepticism: the
scepticism which claims that the real world may not be exactly as I experience it.
The Virtual Reality Argument
It is interesting to consider how Descartes might have approached the question of how I
can be certain that there is a world beyond my mind, had he been writing in the 21st
century, rather than the 17th century.
Our 21st century Descartes might argue like this:
‘At the same time I must remember that I am living in the 21st century, at a time when
virtual reality software can lead to my having amazing experiences. I can fly spacecraft,
race stolen cars around Los Angeles, fight in a medieval battle, land a jumbo jet at
Heathrow – and all without leaving my own bedroom. I often get so caught up in these
virtual reality games that I forget that it is virtual reality. I have often been brought back
with a jolt to reality when my mobile phone rings, so realistic has the experience of the
game been.’
Now here comes the important part:
‘At this moment it does seem to me that I am experiencing reality, and not virtual reality;
what happens in computer games does not appear so clear, or so distinct as does all of
this. But how do I know that all of my experience is experience of reality, and not of virtual
reality? How do I know that I haven’t been experiencing virtual reality for the whole of my
life? In dwelling carefully on this reflection I see so manifestly that there are no certain
indications by which we may clearly distinguish reality from virtual reality that I am lost in
astonishment. And my astonishment is such that it is almost capable of persuading me
that I am now experiencing virtual reality.’
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Support Notes: Philosophy – Epistemology Higher
If you have seen the film The Matrix and its two sequels then you will know that this is
exactly what has happened in these films to almost all of the world’s population. They
experience a computer-generated dream world: the illusion of a world that no longer
exists. The illusion is fed into the brains of these millions of people, who are actually
unconscious, in slime-filled cocoons. To them, the virtual world seems to be real. They
have the experiences of going to school, watching television (and playing virtual reality
computer games), going to football matches, and believing that they are physically doing
all of these things, when they aren’t. They are only doing them virtually.
The writers of The Matrix clearly based their film screenplay on books such as Descartes’
Meditations and Plato’s Republic, which has similar lines of thought.
For the people in their cocoons, there are no certain indications by which they may clearly
distinguish reality from virtual reality. Every experience that they have is an experience
which is caused by the matrix.
Activity 8
What convinces you that you aren’t plugged into a virtual reality machine right now?
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Rebuilding Knowledge
Recap
We have now reached the end of Meditation 1. It is worth pausing at this point to
consider the position which Descartes has reached.
Descartes’ objective is to produce ‘a firm and permanent structure in the sciences’ – in
other words, his objective is to show that the sceptics are wrong.
He aims to do this by showing that if we push scepticism as far as we possibly can –
treating even slightly doubtful beliefs as if they are absolutely false – we will still
nevertheless arrive at knowledge.
The three arguments about doubt – based on (i) problems with the senses, (ii) the Dream
hypotheses and (iii) the Demon hypothesis – have taken us to the point where both
sensory evidence (a posteriori) and evidence based on reason (a priori) have been put
aside as subject to doubt.
At the beginning of Meditation 2 (which is supposed to be day two of his investigation),
Descartes seems depressed by the scale of the task which he now faces:
‘The Meditation of yesterday filled my mind with so many doubts that it is no longer in my
power to forget them. And yet I do not see in what manner I can resolve them; and, just
as if I had all of a sudden fallen into very deep water, I am so disconcerted that I can
neither make certain of setting my feet on the bottom, nor can I swim and so support
myself on the surface.’
He repeats the Method of Doubt at this point:
‘I shall nevertheless make an effort and follow anew the same path as that on which I
yesterday entered, ie. I shall proceed by setting aside all that in which the least doubt
could be supposed to exist, just as if I had discovered that it was absolutely false; and I
shall ever follow in this road until I have met with something which is certain, or at least, if
I can do nothing else, until I have learned for certain that there is nothing in the world that
is certain.’
Note how he is, it seems, beginning to think that perhaps the sceptics are right after all
and that a firm and permanent structure in the sciences is just not possible, and so ‘there
is nothing in the world that is certain’.
Descartes refers to the ancient Greek thinker Archimedes. Archimedes had discovered
the principle of leverage: the longer the plank being used, the greater the weight which
could be lifted. If he had a long enough plank, and could climb high enough, a man could
lift an elephant, using the plank as a lever.
‘Give me but one firm spot on which to stand, and I will move the earth.’ (Archimedes
(c.287-212 BC)).
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Descartes makes the analogy:
‘Archimedes, in order that he might draw the terrestrial globe out of its place, and
transport it elsewhere, demanded only that one point should be fixed and immovable; in
the same way I shall have the right to conceive high hopes if I am happy enough to
discover one thing only which is certain and indubitable’.
If he can find just one belief which escapes the Method of Doubt – one belief which just
cannot be doubted – then, Descartes suggests, he can be optimistic that he can use this
as a foundation, on which to build his ‘firm and permanent structure in the sciences’.
Activity 1
Read the first three paragraphs of Meditation 2.
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The Cogito
At this point, it occurs to Descartes that there is something that the demon cannot do. He
cannot deceive me into thinking that I exist, if I do not. In order to be deceived, I have to
exist.
So even if the Evil Genius does exist, and is omnipotent, there is a limit in his powers. He
cannot deceive a non-existent being (he could not, for example, deceive a fictitious
character such as Harry Potter or Frodo Baggins into believing that he existed). It is a
necessary condition for being deceived that you exist in the first place.
To say that it is a necessary condition for being deceived that I exist is to say that unless I
exist I cannot be deceived (compare: to say that it is a necessary condition for my being a
father that I be a man is to say that unless I am a man, I cannot be a father).
Note how we can also say that if I am a father, then I must be a man (I cannot be a father,
but fail to be a man). Philosophers put this point by saying that it is a sufficient condition
for my being a man that I be a father. So we can say that it is a sufficient condition for my
being deceived that I exist. As Descartes puts the point: ‘without doubt I exist if he
deceives me’.
Not only is it a sufficient condition of my existing that I am deceived; any mental state that
I may be in provides a sufficient condition for my existing. Think of the mental states that
Descartes has been in so far. A partial list includes:
•
•
•
•
•
•
detecting
doubting
wishing
believing
examining
imagining.
If I do any of these things – if I undertake any mental process – I must exist in order to do
this. Descartes has at last found a belief which it is impossible to doubt:
‘So that after having reflected well and carefully examined all things, we must come to the
definite conclusion that this proposition: I am, I exist, is necessarily true each time that I
pronounce it, or that I mentally conceive it.’
In another of his texts, the Discourse on Method of 1637, Descartes makes the point as
follows:
‘I noticed that whilst I thus wished to think all things false, it was absolutely essential that
the “I” who thought this should be somewhat, and remarking that this truth I think,
therefore I am was so certain and so assured that all the most extravagant suppositions
brought forward by the sceptics were incapable of shaking it, I came to the conclusion
that I could receive it without scruple as the first principle of the Philosophy for which I
was seeking.’
The phrase ‘I think, therefore I am’ is perhaps the most famous phrase in the history of
philosophy. Descartes wrote his texts in Latin and in French. The Latin for ‘I think,
therefore I am’ is ‘Cogito ergo sum’ – hence the reference in SQA documents for this
course to ‘Descartes’ cogito’. ‘The cogito’ is philosophers’ shorthand for ‘the argument
which states that “I think, therefore I am”’.
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Descartes is suggesting here that what can be known with absolute certainty is ‘I am’ (as
he puts the point in the Meditations: ‘I am, I exist’. How do I know that I exist? Because I
think. In this argument, ‘I think’ is the premise (a premise in an argument being the
evidence which is offered in support of the conclusion), and the conclusion (what the
argument is intended to prove) is that ‘I am’.
Descartes’ proposal is that it is not possible for ‘I think’ to be true, and ‘I am’ to be false.
We can express this in at least two ways:
1. ‘I think’ means ‘I am’; or
2. ‘I think’ is sufficient for ‘I am’.
Notice how Descartes believes himself to have seen off his sceptical opponent: even ‘the
most extravagant suppositions’ which the sceptic may bring forward cannot cause me to
doubt that I exist.’
Note also how Descartes proposes that ‘I exist’ can be taken as a ‘first principle’. Recall
his earlier ‘Archimedes’ point; recall also his decision, in Meditation 1, to ‘build anew from
the foundation’. His belief that he exists, a belief which is absolutely ‘certain and assured’,
will be the foundation for Descartes’ ‘firm and permanent structure in the sciences’.
Activity 2
Why is the phrase ‘I think, therefore I am’ special? Write a paragraph outlining your
answer.
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The Role of God
It now becomes necessary for Descartes to introduce an argument for the existence of
God. Descartes has as his foundation the one thing that cannot be doubted – the fact that
‘I exist’. But he is a long way from answering the sceptical argument, a long way from
putting more of his ‘apples’ back in the barrel. Remember he started this process by
saying that it would be necessary to put everything to one side, like a man emptying a
barrel of apples to look for any rotten ones to discard. Just about all the apples have
been put to one side, and we have now reached the point where Descartes wants to start
putting ‘apples’ back in – but we need a starting point. How is he to rescue a posteriori
evidence? How is he to argue that evidence about the nature of things taken from the
senses can be rescued from doubt?
His starting point is to establish that God exists. Remember the table we looked at some
time ago that identified the ‘properties’ of God that were agreed by philosophers?
In proving that God exists, Descartes makes use of an assumption which can be
expressed as follows:
What is more perfect cannot arise from what is less perfect.
This is usually referred to as the ‘causal adequacy principle’.
Step 1 in this proof comes with something which Descartes finds in his own mind. He has
an idea of a perfect being. I am imperfect – because I can get things wrong, and because
I can doubt the truth of my beliefs. In order for me to grasp my own imperfection, I must
have an idea of a perfect being – so that I can contrast this with my idea of myself.
Descartes believes that this is true for all of us: if we introspect – look inside our own
minds – we will discover that we have an idea of a perfect being.
Step 2 employs the assumption that nothing will come of nothing. The idea of a perfect
being must have a cause. There must be an answer to the question: ‘how did I come to
have this idea?’
Step 3 employs the causal principle: ‘the more perfect cannot be caused by the less
perfect’. If a perfect thing exists, then it must have been caused by a perfect thing.
Step 4 returns to the idea of a perfect being which I find to be in my mind. The idea of a
perfect being is a perfect idea. A perfect idea must have a perfect cause. I can’t be the
cause of this idea myself, because I am imperfect. So there must exist a perfect being,
who placed this idea in my mind.
Descartes later gave an example: a very perfect machine. Before the machine is built, the
idea of it is in the mind of the engineer who designs it: ‘Just as the complexity belonging
to the idea must have some cause, namely the knowledge of the engineer, or of someone
who passed this idea on to him, so the idea of God which is in us must have God for its
cause.’
At the end of Meditation 3, Descartes compares God to ‘an immense light’ which
illuminates ‘my darkened intellect’.
The syllabus refers to ‘clear and distinct perceptions’. ‘Perception’ must not be taken to
mean sensory perception. ‘Perception’ is Descartes’ term for what the mind does when it
becomes aware of simple truths.
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In another of his texts, the Principles of Philosophy, he states: ‘I call a perception clear
when it is present and accessible to the attentive mind, just as we say that we see
something clearly when it is present to the eye’s gaze and stimulates it with a sufficient
degree of strength and accessibility’.
Elsewhere he gives examples of clear and distinct ideas:
‘That I exist so long as I am thinking, or that what is done cannot be undone, are
examples of truths in respect of which we manifestly possess this kind of certainty. For
we cannot doubt them unless we think of them; but we cannot think of them without at the
same time believing that they are true’.
Descartes thus derives a ‘truth rule’ known as the clear and distinct rule:
‘Whatever I clearly and distinctly perceive is true.’
Once he has this truth rule, Descartes can employ it in order to arrive at his ‘firm and
permanent structure in the sciences’. What is clearly and distinctly known cannot be
doubted – and can therefore be put into the category of certain knowledge.
This is sometimes referred to as the Trademark Argument. As Descartes suggests, in
creating me, God must have ‘placed this idea within me to be, as it were, the mark of the
craftsman stamped on the work’. The proof that God exists – that there is a most perfect
being – is crucially important. The reason for this is that a perfect being will not be a
deceiver. The perfect being, in other words, is not the Evil Genius.
How will the perfect being relate to the Evil Genius? Well, the perfect being must be
omnipotent – all-powerful – and so must be able to control the Evil Genius. The Evil
Genius cannot therefore be omnipotent, because he is under the control of God. God will
also be omniscient (he is perfect, therefore he is all knowing). So he knows what the Evil
Genius is up to in trying to deceive me. Because he is perfectly good, God will not allow
the Evil Genius to deceive me. The Evil Genius hypothesis can therefore be dropped.
What this does is to restore ‘reason is reliable’ as a foundational belief. God acts as a
‘guarantor’ of all the discoveries of reason – of all the clear and distinct perceptions, such
as the cogito, the principle that everything must have a cause, and the causal adequacy
principle.
Note what has happened here. Descartes is a rationalist. He aims to arrive at his firm
and permanent structure in the sciences using reason: using as a foundation, or first
principle, ‘reason is reliable’.
How does Descartes know that reason is reliable? Because God is reliable. Descartes
has reintroduced the fourth foundation that ‘God is reliable’. He has done it in an
interesting way: instead of revealing himself through scripture, he reveals himself by
leaving his trademark inside me. Once I reflect on that trademark, I come to see that
reason is reliable (reason will, after all, be the faculty by which God perceives his own
creation so that in trying to get as close as possible to a God-like understanding, a firm
and permanent science, it is appropriate that I use reason).
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So Descartes’ rationalism is based on an appeal to God’s benevolence. God is reliable
both in that his understanding of everything is reliable, and in that he will not allow me to
go wrong – as long as I use my reason carefully. In using my reason carefully, I will trust
only clear and distinct perceptions, and the firm and permanent structure in the sciences
will be firm and permanent because of its comprising only God-guaranteed clear and
distinct perceptions.
Activity 3
Explain the Trademark argument in your own words.
Activity 4
Descartes believes that whatever he perceives clearly and distinctly must be true. Can
you foresee any difficulties with using this as a test for knowledge?
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Critical Evaluation of Descartes
Descartes brought a new perspective to the world of philosophy, and it is for that reason
that he is regarded as the ‘father of modern philosophy’. Until his work, philosophical
argument had been dominated by the work of certain ‘authorities’ in particular Aristotle.
For the most part philosophers had been concerned with issues of definition and the
meaning of words rather than with observations about the world.
As it was the way in which people thought about the world was being radically
transformed during Descartes own life. New thinkers such as Kepler, Galileo and Newton
changed the way science people thought about the world and Descartes was an
important figure in that process of transformation.
When we talk about strengths and weaknesses what we are focusing on is those areas in
an argument that seem to have answered major difficulties and those areas where there
are problems, where difficulties exist that don’t seem to have been dealt with. Let’s begin
by considering some of the problem areas with Descartes argument.
1. The Cartesian Circle
One difficulty we might have with Descartes’ argument is the role played by God.
Whether or not we believe in a deity is not the issue; what we might have trouble with is
the argument that Descartes used to ‘prove’ the existence of God. According to
Descartes there are certain truths that are so clear, so self-evident that we simply know
them to be true and one such truth concerns the existence of God. The existence of God
then establishes the truth of the existence of the world. This has been described as ‘the
Cartesian circle’ for the simple reason that it could be seen as a kind of circular argument.
I know that god exists, God exists, and therefore I know that the world exists. But if we
need God in order to know that the world exists if we need God in order to establish the
reliability of our mind and our senses, how can we be certain about the reliability of the
reasoning we used to show that God exists? This argument about Descartes’ position
was first raised by a contemporary of Descartes a man called Antoine Arnauld.
Descartes made more than one attempt to answer the criticism and these answers have
been debated by philosophers ever since. On one occasion he seemed to be saying that
we just have to accept that there are some things that by our nature we are inclined to
believe and we just have to live with that – there is no better or more certain way to deal
with the problem.
2. The Dream Argument
There is a problem about this dream hypothesis that Descartes has put forwards after all,
he has said himself ‘there are no certain indications by which we may clearly distinguish
wakefulness from sleep’ when we are asleep, there just are these indications, ways of
checking, when we are awake.
What are the ways of checking? Well, dreams tend to be largely visual. We don’t tend to
have a sense of touch in dreams. Dreams do not have the continuity of waking
experience – they are perhaps convincing at the time when we are having them, but they
tend to be brief episodes, rather than prolonged experience, as being awake is. Dreams
may also have strange elements in them. One of the reasons why you feel relieved (or
perhaps disappointed) on waking and finding that you have ‘only been dreaming’ is that
dreams can be far removed from reality.
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Descartes seems, then, to have made an error. He takes the (true) proposition:
‘I regularly mistakenly take dreaming experience for conscious experience when I am
dreaming’
to lead to the (false) proposition:
‘I cannot ever tell the difference between dreaming experience and conscious experience’
so that:
‘I cannot tell whether I am awake or asleep now.’
So perhaps his argument for doubting the senses has some difficulties.
3. The Clear and Distinct Rule
The idea that there are certain things which we know are true simply because they are
‘clear and distinct’ is problematic. Descartes himself agreed that sometimes it was difficult
for us to know what was ‘clear and distinct’ and at the same time he made it clear on
more than one occasion that he considered man to be ‘subject to error’ – which implies
that there will be – must be – problems with the ‘clear and distinct’ rule.
Strengths of Descartes
Descartes brought a new perspective to philosophy, a more rigorous, a more scientific
approach than that which had been taken before him. His arguments powerfully
influenced the philosophers that followed him, those that chose to disagree with his views
nevertheless had to acknowledge his importance and had to try to deal with his
arguments.
His vision of a unity of the sciences has not been fully realised, but in the modern
sciences there is a recognition that many of the processes scientist are interested in
spring from the same basic interaction of forces, so perhaps Descartes vision will be
realised at some point in the future. In any case his perspective on science was
revolutionary and provided many who followed with an inspiration and direction that
shaped their work.
Cartesian doubt proved a strong method and for many philosophers thereafter the idea of
starting with doubt in order later to try to establish certainty seemed an appropriate tactic.
Indeed some never moved beyond the idea of doubt and embraced the idea of
uncertainty.
Whole new arguments in philosophy were generated by Descartes work, arguments
about the nature of the relationship between the mind and the body, about the nature of
things, and about the nature of self. His influence upon European thinkers in the era that
followed was very great indeed. Whether we agree with his arguments or not, Descartes
demands that we think about matters in a different way and his invitation to follow him on
a personal journey of examination and reflection remains as powerful today as ever.
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Descartes’ Argument – A Summary
In order to better organise and make systematic the discipline of philosophy, it is
necessary to bring to it a method which will assist us in arriving at firm conclusions.
This method begins with the application of Cartesian Doubt. That is to say, everything
that can be doubted, even things that are probably true but about which some form of
doubt can be identified, needs to be set aside in the search for that which cannot be
doubted.
In order to pursue this idea of doubt, there are three levels or kinds of doubt that can be
identified.
In the first case because of the fact that the senses can be misled and confused we
should start by doubting whatever knowledge might arise from their operation.
In the second case, some kinds of immediate sensory information might seem to be
reliable but when we admit the possibility that what we think we are experiencing might
actually only be a dream – then this kind of information too must be subject to doubt.
With these two arguments Descartes feels that he has set aside all arguments for the
certainty of empirical that is to say a posteriori evidence.
In the third case, he turned his attention to knowledge based on reason, that is to say a
priori evidence and in this case he asked us to imagine that a Demon was deceiving us
about such matters, and argued that – unlikely thought that might seem – in such an
extreme case then even evidence based on reason alone should be doubted and set
aside.
Having eliminated most if not almost all of what we could or can know Descartes then
asked – in effect – what was left? He came to the conclusion that the one thing that could
not be doubted was the existence of the doubter. There had to be something doing the
doubting, asking the questions, thinking about the nature of things, and that led to the
expression ‘I think, therefore I am’, or to put it in the Latin, ‘Cogito Ergo Sum’.
From that first statement, Descartes then sets about to re-build certainty but now not on
the basis of unexplored arguments and vague ideas, but upon the firm basis that he has
established. From the existence of the thinking self he establishes the notion that there
are certain things we know, such as the idea of perfection, that can only be explained by
the existence of perfection – in other words by the existence of God. Once we have
accepted the existence of God we have to then accept that there is no Demon able to
deceive us about the workings of reason, so a priori knowledge is established upon a firm
basis, and then we have to recognise that the world about is the creation of God as is our
senses and that therefore, so long as we use them properly, the senses too are reliable
and tell us about a real world, not a dream.
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David Hume
David Hume was born in Edinburgh, probably in the family’s home in the Lawnmarket, on
26 April 1711. He attended Edinburgh University at the very early age of 11, and had
completed his first great philosophical work by the time he was 25. His family were
landowners and farmers, though not what would have been considered wealthy. His
father died while David was quite young, and it was clear that he had no talent for running
the farm and lands – so his brother took on that responsibility.
At first David was not a very successful academic! He laboured for many years to
produce his first book – however it was not successful and did not earn for him the kind of
fame and recognition he expected. In an attempt to assist his family’s finances he took
various other forms of employment – but again he was not terribly successful and
eventually returned to his first interest. His six-volume history of England made his
reputation as an historian, and he settled down, travelling between the family farm and
Edinburgh to a comfortable life as an established academic and man of letters.
However it would be wrong to think of Hume as a safe and respectable country gent of
the 18th century – he is much more than that. Hume was considered by many of his
contemporaries as a dangerous man!
Although the main Arts building of Edinburgh University is named David Hume Tower, the
university turned Hume down when in 1745 he applied for a job there. The street in which
he lived in the final years of his life is named after him: South Saint David Street, which
runs from Princes Street to St Andrew Square (the name is a joke; one of the main
reasons why Hume was turned down by the university was that he was notoriously
sceptical about religion). Hume is buried in Calton cemetery in Edinburgh, and has
recently been commemorated by a statue outside the High Court on the Royal Mile.
When Hume died, his close friend Adam Smith – who was also a very eminent
philosopher – wrote as his epitaph:
‘Upon the whole, I have always considered him, both in his lifetime and since his death,
as approaching as nearly to the idea of a perfectly wise and virtuous man, as perhaps the
nature of human frailty will permit.’
Hume has a claim to being one of the most outstanding figures of British philosophy. Not
so much because of his influence upon others but simply because of the depth and
quality of his work. By contrast the work of John Locke both as a political writer and as a
philosopher, had much more impact – although, curiously enough, Locke was not an
outstanding thinker in the way that Hume was. To some extent this might be because the
kind of things Locke had to say fitted the mood and needs of his day, they were not
terribly demanding or challenging whilst by contrast, Hume was difficult! Difficult because
he was sceptical and critical and had a reputation for being an atheist.
Hume is an important figure in the Scottish Enlightenment – an intellectual movement in
the 18th century, based mainly in the universities of Aberdeen, Glasgow and Edinburgh.
These Scottish cities were referred to as ‘hotbeds of genius’, where men such as Hume
carried out ground-breaking work in philosophy – but also in economics, art, law,
architecture, medicine, engineering, and science. The Scottish Enlightenment challenged
the beliefs of the past, presenting a new way of understanding human beings and their
place in the world.
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To a great extent, the social sciences were invented at this time. As we shall see, Hume
did important work in what comes to called psychology; the Kirkcaldy-born Adam Smith is
sometimes referred to as ‘the father of economics’, and Adam Ferguson (who was born in
Logierait in Perthshire) did pioneering work in what came to be sociology.
The project of the Scottish Enlightenment thinkers is sometimes described as being a
‘Science of Man’. Hume sets out in the text which we are to study – An Enquiry
Concerning Human Understanding (1748) – to provide a science of human nature. Hume
had earlier stated that his ambition was to be ‘the Newton of the Moral Sciences’. The
great English thinker Sir Isaac Newton had, in the previous century, studied natural
events such as the motion of the planets and the tides, and had been largely responsible
for a new scientific way of understanding the world. Newton had suggested that ‘moral
science’ (by which he meant what we would call ‘social science’ – the scientific
understanding of man) could be carried out using the same scientific method that Newton
had used in carrying out his science. This method – the ‘experimental method’ – is an
empiricist method. The starting point for this kind of science is very careful observation.
Newton produced laws of gravitation, which described how physical objects behave; this
description was based upon very close study of the ways in which these bodies appeared
to behave.
Hume’s aim, then, is to discover laws of human perception, desire, feeling, belief, and
reasoning. His starting point is empiricism.
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The Egocentric Predicament
You will recall that we started off by discussing the difference between rationalism and
Empiricism. Rationalism starts with this central idea that some of the knowledge we have
is based not on experience – but on the operation of reason alone – it is innate. We just
know that some things are true. Rationalists do not deny that people learn by experience,
they just think that our starting point is knowledge that is hard-wired so to speak – that is
already in our minds. However by the 17th century important philosophers and thinkers
were questioning that idea. Science was just in its infancy, but intellectuals and thinkers
were getting caught up in the idea that the world was a place that could be studied and
taken apart and examined to see how it worked. The idea that we could learn to better
understand the world was taking hold.
A young doctor and writer called John Locke called into question the whole notion of
innate ideas. He started by trying to identify an idea so basic, so fundamental that it had
to qualify as innate knowledge – if such a thing existed. He started with the statement –
‘what is, is and what is not, is not’. This basic statement about existence he argued had to
be so fundamental that it must be part of innate knowledge – if such a thing existed. So
we would expect therefore that if we asked children or people from other lands what they
understood by the statement why then – because this knowledge is innate – they would
completely understand what was meant by it. However, if they failed to recognise the
statement and understand its meaning – it would indicate that there was no such thing as
innate knowledge.
Locke did not conduct a full-blown survey of people for this ‘test’ but he was satisfied that
on the whole people did not recognise immediately what the statement meant and that in
turn meant that there was no such thing as innate knowledge – the key idea of
rationalism. Instead, Locke argued, we are all tabula rasa – blank slates – upon which
experience writes. In other words, all knowledge arises from experience.
Locke went on to try to establish that knowledge gained from experience could
nonetheless be accurate and certain. However there is a real problem about this.
Sceptics had for hundreds of years questioned the idea that we could have certainty, that
our knowledge of the world could be relied upon as ‘true’. Locke in effect had given
additional fuel to their case. If each and every one of us learns only by experience – and if
those experiences are different – how can we arrive at the ‘truth’?
This ‘egocentric predicament’ left empiricists with a real problem. We can study the world
and learn about it through our experiences, but can we have any certainty about the
knowledge we gain? Can we even arrive at agreement between ourselves as to what the
truth is given that we are all different and have different viewpoints?
Activity 1
Do you think that because everyone’s experience is different – that means we can never
arrive at the truth? Take a TV programme or a film that you and some of your classmates
have watched recently. In groups, try to write down the main events of that film or
programme and note what differences there were between you and your classmates. Can
you arrive at an agreement about what took place? What do you think this tells you about
knowledge?
Hume started with this empiricist view. He begins in his Treatise by talking about the
perceptions of the human mind – how we know and understand things and resolved our
perceptions down to just two things, impressions and ideas.
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Impressions and Ideas
When we began this journey we started by arguing that knowledge is justified, true belief.
An enquiry concerning human understanding will, among other things, investigate:
•
•
how we come to have the beliefs that we do
and will also attempt to answer the question of what beliefs are.
Hume is, therefore, doing what we now call ‘psychology’.
In order to give an account of the functioning of the mind – of the operation of the human
understanding – Hume needs first to give an account of the contents of the mind. All of
the mind’s processes – sensing, feeling, reasoning, etc. – have to be about something;
some content of the thinking is required.
Hume describes all of these mental contents – all of the contents of thinking or feeling –
as ‘perceptions’.
Key Point
If you have studied Psychology, then you will have come across the word ‘perception’
there. In 21st century Psychology, perception is a process – it is the process of the mind’s
interpreting the results of sensation, such as the vibrations in the eardrum which cause
activity in the auditory nerve in the brain – which is interpreted as a particular sound.
It is important to stress that this is not what Hume means by ‘perceptions’. For Hume a
perception is an entity and not a process. When Hume talks about perception he is
referring to a specific thing, an item in the mind, rather than a set of sensory operations.
Because of the potential for confusion over the word ‘perception’, as Hume uses it, this
unit will from now on refer to ‘perception’ in quotation marks, to remind you that it is being
used in Hume’s sense, and not in the modern sense.
Activity 2
Write a short note on what you understand to be the difference between modern use of
the work ‘perception’ and how Hume used it.
Hume opens Section 2 of the Enquiries by making an important distinction:
‘Every one will readily allow, that there is a considerable difference between the
perceptions of the mind, when a man feels the pain of excessive heat, or the pleasure of
moderate warmth, and when he afterwards recalls to his memory this sensation, or
anticipates it by his imagination.’
The contrast here is between what is in your mind when, for example, you put your hand
into a fire, and what is in your mind when you later remember having done this – or when
you merely imagine doing it.
We can try this out for ourselves: imagine, right now, putting your hand in a flame. The
experience just is not as unpleasant as actually doing it would be – is it?
The same goes for ‘the pleasure of moderate warmth’. Remembering the pleasure of
lying on a beach in the Mediterranean, or imagining it just isn’t the same as actually doing
it – actually lying on the beach (if it was, holiday companies would be in big trouble).
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So Hume has made a distinction between:
Actually experiencing heat
as pain or pleasure
and
Remembering the heat
as pain or pleasure –
or even imagining
the heat as pain or pleasure.
This is what Hume says about remembering and imagining:
‘These faculties may mimic or copy the perceptions of the senses; but they never can
entirely reach the force and vivacity of the original sentiment.’
So we can make various distinctions
1. First we have perceptions arising from our senses.
2. The memory of these perceptions is a copy of the original.
3. The imagination can provide a weaker recreation of the original.
So:
1. Perceptions arising from the senses are much stronger and more vivid.
2. Remembering and imagining perceptions is a much weaker less vivid experience.
So Hume is identifying a difference between perceptions in terms of their force and their
vivacity.
What is this difference?
Well, consider two points:
If you burn yourself – you don’t
need to make any deliberate
effort to feel the pain – the
perception is immediate and
vivid – or dominant and even
some time later you don’t
have to make a great effort to
remember the pain.
However no matter how well you can
recall the pain – it won’t be the same
sensation as the original experience
no matter how you try to re-create the
intensity of the original experience –
it simply is not the same – not as vivid
or dominant.
So we have more lively and vivacious ‘perceptions’, and less lively and vivacious
‘perceptions’. The less lively and vivacious ones – those which result from the operation
of the memory or the imagination – will just never be as lively and vivacious as the
‘perceptions’ of the senses. As Hume puts the point:
‘The utmost we say of them, even when they operate with greatest vigour, is, that they
represent their object in so lively a manner, that we could almost say we feel or see it:
But, except the mind be disordered by disease or madness, they never can arrive at such
a pitch of vivacity, as to render these perceptions altogether undistinguishable.’
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It might be that someone who is unbalanced mentally might be able to imagine things
with great intensity – including pain. However even if it is possible for someone who is in
that condition to conjure up or hallucinate about experience, and perhaps as a result feel
an extreme emotional response, even then would the imagined perception be as strong
as ‘the real thing’? ‘The most lively thought,’ Hume suggests, ‘is still inferior to the dullest
sensation.’
This is a powerful point – even the most extreme and vivid imaginative event is not equal
in intensity to the ‘dullest sensation’. If that is the case, then it marks a clear division
between perceptions of real things, and the operations of our imagination.
Hume points out that this applies to every kind of perception. Another example that he
gives is of the difference between a man who is feeling anger, and a man who merely
imagines being angry.
Activity 3
You can try out Hume’s distinction for yourself.
1. Go over to the window of the room that you are in and look at the view outside. As you
look, there will be ‘perceptions’ in your mind of the various buildings, people, trees, cars,
and so on which are outside.
2. After a few moments, stop looking and go back to your seat. Now call to mind the
scene which you have just seen.
What is the difference between the ‘perceptions’ in (1), and those in (2)?
There should be two main differences:
1. While it requires no effort at all to have the visual ‘perceptions’ which you have while
looking out of the window (and in fact you cannot will yourself not to see what is
there), it does require some effort to call to mind the scene – to have the ‘perceptions’
of the buildings, trees, etc., which memory provides; and
2. Much of the detail which was present in the visual ‘perception’ is absent in the
memory-generated perception.
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Impressions and Ideas II
Hume drew a particular distinction between ideas and impressions which we have
already tried to capture. Impressions, he argued were more ‘lively’ more ‘vivid’ than ideas.
Hume labels the two ‘perceptions’ in this way:
Impressions
Impressions are vivid and immediate
‘perceptions’ – which we get from the
operations of the senses – and from
immediate feelings like anger, pain,
jealousy, guilt.
Ideas
Ideas are less lively and immediate –
not as vivid as ‘perceptions’ which we
get from remembering, or imagining
things such as pain, smells, sounds
and from imagining or remembering
feelings like anger, fear, guilt.
We need to be careful about terminology. An ‘idea’, as Hume uses the term, is what is in
the mind whenever I remember something, or imagine something. The idea is the content
of that mental operation.
Over time the immediacy and strength of an idea tends to diminish. Things we recall that
caused us pain or happiness tend to lose their force. Faces, people, events that were
once strong ideas in our minds, gradually fade. Ideas then are things that might vary in
clarity and strength, or to the extent to which they carry strong emotional content.
What was in your mind during the earlier experience itself is an impression. Why
‘impression’? What Hume may have in mind is something which was common in the 18th
century, before the development of the modern post office (and before the use of
envelopes). When Hume wrote to his friend and fellow philosopher Adam Smith, he had
written the letter, and then sealed it. Hume would likely have had his own personal stamp.
He would heat a piece of sealing wax, pour it on to the fold on the paper, then put his
stamp into the molten wax. This would leave an impression in the wax (which Smith
would recognise, on receiving the letter from his friend). The stamp impresses itself in the
wax, so that there is now something in the wax which resembles the stamp. Similarly, the
world outside the mind impresses itself on the mind when I look at it, or listen to it, etc.
So we take up impressions based on the operation of our senses, which in turn give rise
to ideas – memories – of what happened. We burn our hand in the fire, the pain is
immediate and vivid – the ‘perception’ gives rise to an impression which in turn gives rise
to ideas in our minds which gradually – over time – lose some of their force, but even
when these ideas are created they cannot be as vivid and strong as the actual experience
was.
There is one final distinction to make. It may seem unimportant – but it will be a very
important distinction in later parts of the Enquiry.
Hume has identified two different types of impression.
There are impressions such as the impression which I have in my mind when I look at a
patch of blue, or taste some red wine, or touch a scrap of velvet, or listen to a passage
from Händel, or smell the horse droppings outside in the street. All of these would be
familiar impressions to Hume.
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There are other impressions which would also be familiar to Hume: the impression in the
mind when I feel disappointment at being rejected for a job, or when I feel happiness at
being in the company of friends, or when I feel the pain of toothache.
This might have occurred to you already when we were considering emotions. Some
emotions might be responses – some might arise from inside us.
We have, therefore, a distinction between:
Outward Impressions – which arise from
the operation of the senses. That is they
begin with something outside of ourselves
having an effect upon us.
Inward Impressions – feelings that
arise inside us, such as guilt
or happiness. These feelings
might happen as a result of what
Hume calls the ‘inward sentiments’.
We would nowadays refer to these as ‘External Impressions’ and ‘Internal Impressions’.
Activity 4
What do you think about this distinction between ideas in the memory and immediate
impressions? Can you call to mind any strong memories that you would consider to be
‘vivid’? Are these memories as strong as what you are at this moment experiencing
thorough the senses?
Write a short note describing Hume’s argument about the difference between ideas and
impressions and end by indicating what you think of this argument.
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Simple and Complex Ideas
Hume recognises the seemingly limitless power of the human imagination:
‘To form monsters, and join incongruous shapes and appearances, costs the imagination
no more trouble than to conceive the most natural and familiar objects. And while the
body is confined to one planet, along which it creeps with pain and difficulty; the thought
can in an instant transport us into the most distant regions of the universe; or even
beyond the universe, into the unbounded chaos, where nature is supposed to lie in total
confusion.’
The imagination is capable of great creativity, we only have to think about films we have
seen, television programs or books we have read which have involved fantastic creations.
The creators of Dr Who provide us with a clear example of how ‘the thought can in an
instant transport us into the most distant regions of the universe’.
There is just one limitation which Hume recognises here – one thing which the
imagination cannot do:
‘What never was seen, or heard of, may yet be conceived; nor is any thing beyond the
power of thought, except what implies an absolute contradiction.’
An ‘absolute contradiction’ arises where we have both a property and its complete
opposite. For example, the following two statements are absolutely contradictory:
•
The book is red. The book is not red.
If we try to imagine an object that is both completely red and at the same time completely
not red, we can’t do it.
Is this the only restriction on the operation of the imagination? Hume thinks not. If we
consider how the imagination operates in creating ideas, we will, he suggests, find a very
important further limitation on its operation.
Hume identifies four things that the imagination does – four ways in which it can arrive at
its ideas:
‘But though our thought seems to possess this unbounded liberty, we shall find, upon a
nearer examination, that it is really confined within very narrow limits, and that all this
creative power of the mind amounts to no more than the faculty of compounding,
transposing, augmenting, or diminishing the materials afforded us by the senses and
experience.’
So the four things that imagination can do are:
1. Compounding. Here the imagination takes two or more ideas from the memory, and
puts them together to create a new idea. Hume provides two examples of this:
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The Golden Mountain
We have an impression in our minds
based upon the experience of seeing
mountain – and we have the idea of
the memory – what we can
then do is put these two things together
to ‘create’ a golden mountain.
The Virtuous Horse
I have an idea of a horse in my memory
having before seen a horse. I have an a
idea of virtue in my mind having seen gold in
someone be virtuous – or for that matter
because I have been virtuous – this
makes it possible to ‘create’ something in my
imagination that I have never experienced –
a virtuous horse.
2. Transposing. To ‘transpose’ is to change the position of a thing. I can imagine the
kinds of monsters which are in science fiction films – or classical literature – by
transposing the parts of animals on to human beings.
3. Augmenting. To ‘augment’ is to increase. My imagination has no difficulty in arriving at
an idea of a mouse which is the size of a tall building, for example.
4. Diminishing is, of course, the opposite of augmenting. I can easily have the idea of a
tiny elephant – or of an elephant with a barely audible ‘trumpet’.
If Hume is right, then we have a complete account of the operation of the imagination.
To see how this account points out an important limitation on the imagination, we need
first to reflect on what exactly the imagination is doing.
This argument really means that there are two different kinds of idea:
Simple Ideas
These are the result of impressions
creating memories – the memory
is a copy of the original impression.
These are (as we have seen) less
vivid and lively than the original and
may fade away over time.
Complex Ideas
These are made up out of one or more
Simple Ideas which have been worked
upon – they have been compounded,
transposed, augmented or diminished
by the imagination. Complex ideas are
not simply copies of impressions – as
Simple Ideas are – and may bear little
resemblance to any actual experience.
So from this view of the imagination offered by Hume, we can identify the limits – the
boundary that it cannot go beyond. The imagination has to have material to work on –
and that material is provided by experience. We can take our previous experiences add
them together, mix them up change them around but there is this limit because we cannot
put two things together in our imagination that implies a contradiction. The imagination is:
‘Really confined within very narrow limits [because] all this creative power of the mind
amounts to no more than the faculty of compounding, transposing, augmenting, or
diminishing the materials afforded us by the senses and experience.’
Activity 5
Take two or more simple ideas and try out Hume’s set of ways to transform these ideas
into complex ideas. Do you think his argument about the limitations of the imagination are
accurate?
Write a short note sketching out what you think.
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No Innate Ideas!
Read the following passage from Hume (a translation into more modern English (and
more modern examples) is provided on the right):
‘If it happen, from a defect of the organ
that a man is not susceptible of any
species of sensation, we always find that
he is as little susceptible of the
correspondent ideas. A blind man can
form no notion of colours; a deaf man of
sounds.’
If someone happens to have a
defect in one of the senses so
that they cannot experience
something it follows from that that
such a person cannot understand
the ideas related to that set of
sensations – a blind man has no
idea of colour – a deaf man no idea of
sounds.
‘Restore either of them that sense in which
he is deficient; by opening a new inlet for
his sensations. you also open an inlet for
the ideas; and he finds no difficulty in
conceiving these objects. The case is the
same if the object proper for exciting any
sensation, has never been applied to the
organ.’
If the blind man gains sight, or
the deaf man his hearing, then
not only will they have access to
sensations of sight and hearing
for the first time, they will also
begin to form ideas based on
these experiences
‘A Laplander or Negro has no notion of the
relish of wine ... A man of mild manners
can form no idea of inveterate revenge or
cruelty; not can a selfish heart easily
conceive the heights of friendship and
generosity.’
Similarly if someone experiences
something which is unfamiliar or
entirely new to them, then they
will begin to form ideas based on
these new sensations. And by the
same argument, a person cannot
have ideas about something they
have never experienced.
What Hume is suggesting here is that there can be no ideas unless there have earlier
been impressions. The man who has been blind from birth will have no idea of the colour
blue. The reason for this is, of course, that he has never had an impression of blue. He
has never looked at the sky on a clear day, or studied the various shades of blue on the
sample cards in a paint shop. Similarly, the Mbuti tribesman in Zaire will have no idea of
the taste of Irn Bru; he as never left Zaire, and Irn Bru is not sold there.
During Hume’s lifetime the Americans, who were rebelling against the British, had a
slogan: ‘No taxation without representation’. For Hume, we can suggest a slogan:
No ideas without Impressions!
All of our ideas come from experience, on Hume’s account. Every idea is either a simple
idea – a copy of an earlier impression which is now in the memory – or it is a complex
idea, in which case the imagination has created it, using as raw materials the simple
ideas stored in the memory. In either case, every single idea has its origin in experience.
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In stating this Hume is clearly putting himself on one side of a long-running debate in
philosophy. Many earlier philosophers had argued about the nature of knowledge. The
epistemological debate had produced by Hume’s time two strong arguments. On the one
hand were those who argued – like Hume – that all knowledge was based on experience,
that knowledge was a posteriori – it arose after experience. That there were – in Hume’s
terms, no ideas without impressions. However many had argued that there was also
innate knowledge. That is the idea that some knowledge was a priori – it arose as a result
of the operation of reason alone – prior to and independent of any experiences.
However if Hume’s argument is correct, then clearly the case for innate knowledge is
overthrown. His argument denies the possibility that knowledge could be innate.
The truth of the empiricist doctrine entails the falsity of the innatist doctrine. That is to say
that if it is true that all knowledge and ideas come from experience (as the empiricists
claims), then that guarantees the falsity of the claim that some knowledge and some
ideas are present in the mind at birth.
As we have seen Locke challenged the idea that there was innate knowledge – Hume
takes that challenge a step further. He completely rejects the notion that there can be
innate ideas. For him the matter is clear, we need do no more than demonstrate that
knowledge of things depends upon the operation of the senses, and upon experience, we
cannot know things that we have not experienced. This has important consequences. But
before we can get there, in an almost casual aside, Hume throws a great spanner into the
works! He raises a question that casts doubt on his own argument; we need to look at
that question before we can move on.
Activity 6
Are you convinced? Is there no such thing as innate knowledge?
What might indicate that some knowledge was innate?
Can you think of any arguments against Hume’s position?
Make a list of what you consider to be the strengths and weaknesses of the arguments
for innate knowledge, and the empirical case.
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The Missing Shade of Blue
No sooner has Hume emphasised his view that there can be no ideas without
impressions, than he appears to contradict himself. There is, he suggests, ‘one
contradictory phenomenon, which may prove that it is not absolutely impossible for ideas
to arise, independent of their correspondent impressions’. This is the notorious ‘missing
shade of blue’ passage. As before, the original is on the left, and a modern translation on
the right:
Suppose a person to have enjoyed his
sight for 30 years, and to have become
perfectly acquainted with colours of all
kinds except one particular shade of
blue, for instance, which it never has been
his fortune to meet with.
Suppose a man of 30 who has
has perfectly good eyesight all his
life has experienced all the
shades of blue – except one.
Let all the different shades of that colour,
except that single one, be placed before
him, descending gradually from the
deepest to the lightest, it is plain that he
will perceive a blank, where that shade is
wanting, and will be sensible that there is
a greater distance in that place between the
contiguous colour than any other.
Suppose that we lay out before
that man all the shades of blue
that he has seen graded from the
darkest blue to the lightest – just
by noting that there is a gap
where the shades jump from one
depth of colour to another –
missing out a shade.
Now I ask, whether it be possible for him,
from his own imagination, to supply this
deficiency, and raise up to himself the idea
of that particular shade, thought it had never
been conveyed to him by his senses?
Would it be possible for this man
to imagine the missing shade
even though he had never
experienced that particular
shade?
I believe there are few but will be of opinion
that he can …
I believe that most people would
agree that he can …
Earlier on we came up with the slogan based on Hume’s argument:
No ideas without Impressions!
Yet here he is providing us with a ‘contradictory phenomenon’ – a case of just that: an
idea without an earlier impression.
Hume responds to this counter-example by dismissing it:
‘… this may serve as a proof that the simple ideas are not always, in every instance,
derived from the correspondent impressions; though this instance is so singular, that it is
scarcely worth our observing, and does not merit that for it alone we should alter our
general maxim.’
In other words, Hume is claiming:
•
this is a proof that we can after all have ideas without impressions, but
•
this case is a one-off, and so:
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•
it isn’t really necessary to take up too much time dealing with it, and
•
it certainly is not necessary that I should withdraw my earlier claim that there can be
no ideas without impressions.
One 20th century commentator, H.A. Pritchard, commented in his book Knowledge and
Perception, published in 1950, that:
‘This is, of course, just the kind of fact which should have led Hume to revise his whole
theory. It is really effrontery on his part … to ignore an instance so dead against a
fundamental doctrine of his own.’
It seems clear that the case of the missing shade of blue is not a one-off: if by some
chance the man had heard every note on a piano during his life, except for one, then
again his imagination could ‘supply the deficiency’.
The missing shade of blue appears to be a problem because it appears to falsify Hume’s
empiricist theory.
Empiricism was defined earlier as the doctrine that all of our knowledge comes from
experience, and all of our ideas come from experience.
We can set this out as follows:
1. If empiricism is true, then there can be no idea which has not come from experience.
2. The empiricist’s opponent – the innatist – will respond that there are ideas which do not
come from experience (innate ideas), so that empiricism is false.
Has Hume, with the missing shade of blue, shown the innatist to be right?
One way of redeeming Hume’s position is to ask the question:
•
Could a blind man’s imagination ‘supply the deficiency’?
The answer is surely that it could not.
Note how the imagination is being referred to here by Hume:
‘I ask, whether it be possible for him, from his own imagination, to supply this deficiency,
and raise up to himself the idea of that particular shade, though it had never been
conveyed to him by his senses? I believe there are few but will be of opinion that he can
…’
The reference to the imagination is important. Remember that Hume has listed four
operations of the imagination:
•
•
•
•
compounding
transposing
augmenting
diminishing.
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This is why the blind man cannot arrive at an idea of the missing shade. There is nothing
which he has experienced which he can compound/transpose/augment/diminish in order
to gain the idea of the missing shade – because he has never seen any colours at all.
The man in Hume’s passage has seen every shade of blue, except for the missing one.
At this point, you should be able to work out for yourself how this man succeeds in
‘raising up to himself the idea of that particular shade, though it had never been conveyed
to him by his senses’.
The process:
•
The man has, at various times, an impression of every shade of blue – except for the
missing one.
•
This results in his having an idea of every shade of blue except for that missing
shade.
•
Because he has an idea of every other shade, he has an idea of the shade
immediately to the right of the missing shade (the slightly darker one), and of the
shade immediately to its left (the slightly lighter one).
•
By diminishing the slightly darker one he can arrive at the missing shade – and by
augmenting the slightly lighter one, he can arrive at the same idea.
•
So from his experience of the other shades, he arrives at the idea of the missing
shade.
So while it is true that neither this man nor the blind man has had experience of the
missing shade, and also true that our man’s imagination can ‘supply the deficiency’, this
does not show that we can have ideas in the absence of experience (if the blind man
could have an idea of the missing shade of blue, then that would pose a big problem for
Hume).
So what does the ‘missing shade of blue’ demonstrate?
Think about this.
What is the difference between the idea which the man has of the other shades of blue,
and the idea which he has of the missing shade?
What it shows is that colour ideas may be simple ideas, or they may be complex ideas.
Because the idea of the missing shade is arrived at through the operation of the
imagination – augmenting and diminishing the neighbouring, simple, ideas – it is a
complex idea. If the man had actually seen the missing shade, then the idea of it would
be a simple idea – an idea in the memory which faithfully copies an earlier impression.
So the missing shade of blue seems only to show that it is not the case that simple ideas
and complex ideas form mutually exclusive classes. For at least some ideas, the same
idea can be either simple or complex. Suppose the man later on sees the missing shade
of blue – gets an impression of it. At that point, he gets a simple idea of what he already
has as a complex idea.
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Activity 7 – Discussion
What do you make of this argument?
In the first case, do you think that you need to have seen every shade of a colour in order
to be able to imagine any particular shade?
If you were asked to imagine a dark olive-green with a hint of red – could you imagine
that colour?
Try this out with your classmates – can you identify colours that no-one can imagine?
If you can – are these colours that involve contradictory statements? Remember our
discussion of imagination previously. Do you think it would be possible to imagine a
shade or colour which you have never seen?
What colour would Ultra-Violet be?
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Hume’s Fork
Up to now we have been concerned with how we come to have ideas – and Hume has
given an empiricist account of how this happens. In the next section of the Enquiry, Hume
turns his attention to how we come to have knowledge, and again his account is going to
be an empiricist one.
To have knowledge is to have justified, true belief.
What is believed is a proposition – such as ‘today is Monday’.
Propositions may be true or false (so that the belief that today is Monday is true if – and
only if – today is Monday).
My true belief that today is Monday is justified if I can provide some evidence in support
of my claim that today is Monday.
Propositions are, therefore, very important in epistemology. The target for belief – what is
believed – is a proposition. The target for knowledge is propositions which are believed,
but are also true and justified.
We have already come across a distinction between beliefs which are a priori (and which,
if true and justified, are a priori knowledge), and beliefs which are a posteriori (and which,
if true and justified, are a posteriori knowledge).
Hume has his own terminology for this distinction.
•
•
a priori he refers to as Relations of Ideas
a posteriori he refers to as Matters of Fact.
Relations of Ideas
Hume tells us that a relation of ideas is ‘either intuitively or demonstratively certain’.
Remember that a key question always to ask is: ‘how do you know?’. Hume is here
suggesting two ways in which we may come to know some relation of ideas: through
intuition, or through demonstration.
The term ‘intuition’ has a particular meaning in philosophy – and this is very different from
how it is used by non-philosophers (when, for example, women refer to something which
they call ‘female intuition’).
In philosophy, some claim is intuitive if it is self-evidently true. Think about what ‘selfevident’ means: the claim justifies itself. Here are some examples:
•
•
•
•
anything that has shape has size
either today is Tuesday or it isn’t
nothing can be bigger than itself
an object cannot be bigger than all of its parts.
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With these propositions, we just have to think about them to see that they are true. We
just immediately ‘see it’. This is what intuition is (it comes from a Latin word, intuere,
which means a kind of intellectual ‘seeing’). Notice how we don’t have to spend any time
wondering whether an object can be bigger than the sum of its parts: the truth of this is
grasped immediately.
The statement ‘an object cannot be bigger than all of its parts’ comes from the Greek
mathematician Euclid. He called statements such as these ‘axioms’. An axiom is a
statement where the truth of the statement is grasped by intuition – we ‘intuit’ its truth.
What does it mean to say that an axiom is self-evident? It means that when we are
asked: ‘how do you know?’ the answer which we are liable to give is: ‘just think about it’.
We do not need to look for further justifying evidence. Anyone who doubts that an object
cannot be bigger than all of its parts either isn’t thinking clearly, or doesn’t really know
what is meant by the statement. The meaning of an axiom guarantees its truth.
So some relations of ideas are ‘intuitively certain’. But not all are: some relations of ideas
are ‘demonstratively certain’.
What makes some claim – some relation of ideas – demonstratively certain is that
we can work out, a priori, that it is true (ie. we can establish its truth just by
thinking – without the need for observation).
As Hume points out, Geometry, Algebra and Arithmetic deal in knowledge which, if not
intuitively certain, is demonstratively certain.
Some claim is demonstratively certain when it is one which can be worked out using
reasoning. An example which may be familiar to you from maths classes is Pythagoras’
theorem: ‘the square on the hypotenuse on a right angled triangle is equal to the sum of
the squares of the other two sides’. Pythagoras worked this out a priori. When he was
asked ‘how do you know?’, Pythagoras had provided a proof – a piece of reasoning which
shows that for any right-angled triangle, it must be the case that the square on the
hypotenuse is equal to the sum of the squares of the other two sides. So a theorem is a
priori and demonstrative, and an axiom is a priori and intuitive.
Why call them ‘relations of ideas’?
Relations of Ideas are, like matters of fact, statements. Every statement asserts a
relationship between two or more ideas.
If we limit ourselves to statements with only two ideas, then we can see how this works:
(a) The cat sat on the mat.
(b) All triangles are three-sided figures.
Statement (a) asserts a relationship between the cat and the mat, while statement (b)
asserts a relationship between triangularity and three-sidedness.
Hume suggests that words lack meaning unless they refer to ideas which we can trace to
earlier impressions:
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‘When we entertain … any suspicion, that a philosophical term is employed without any
meaning or idea … we need but enquire, from what impression is that supposed idea
derived? And if it be impossible to assign any, this will serve to confirm our suspicion.’
Now if we return to our two statements above, while statement (a) asserts a relationship
between the idea of the cat and the idea of the mat, I can only test the statement for truth
or falsity (I can only answer the ‘how do you know? question) by checking the world
outside of my mind. I have to look at the mat, to see whether the cat really is on it. That
makes the statement ‘the cat sat on the mat’ a matter of fact: it is a statement, the truth of
which can only be established a posteriori.
Statement (b), on the other hand, requires no such checking of the way the world is. Here
the two ideas – triangularity and three-sidedness – are related in such a way that it just
has to be the case that anything that is triangular will be three-sided. So a priori reflection
on these ideas is all that is needed to establish the truth of the claim. That makes the
statement ‘all triangles are three-sided’ a relation of ideas.
Hume later observes, regarding Relations of Ideas, that:
‘Propositions of this kind are discoverable by the mere operation of thought, without
dependence on what is anywhere existent in the universe. Though there never were a
circle or triangle in nature, the truths demonstrated by Euclid would for ever retain their
certainty and evidence.’
Notice how relations of ideas do not depend on how the world happens to be. Even if the
world had never existed at all, Pythagoras’ theorem would still be true.
A statement which is true and could not possibly not be true is a necessary truth. The
statement ‘no triangular object is circular’ is necessarily true: true, and could not possibly
not be true.
Activity 8
Consider these statements and think about how you would know them to be true or false.
(a)
(b)
(c)
(d)
All swans are white.
All bachelors are men.
The world is round.
2 x 2 = 4.
Write a short note for each one explaining your answer.
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Matters of Fact
The distinction between Relations of Ideas and Matters of Fact is usually referred to as
Hume’s Fork.
As we have just seen, relations of ideas ‘are discoverable by the mere operation of
thought’. As Hume points out, when we come to consider matters of fact, they are ‘not
ascertained in the same manner’.
Consider the following two propositions:
(a) No triangles are circular.
(b) Some road signs in the UK are circular.
Proposition (a) here is a relation of ideas. All that I have to do to ascertain the truth of (a)
is to think about it. My idea of a triangle, and my idea of a circle are such that it is just
impossible for any object to be both triangular and circular. Proposition (a) is necessarily
true.
How do I know that proposition (b) is true? If I am asked ‘how do you know that some
road signs in the UK are circular?’, I can’t answer by saying ‘well, you just have to think
about it’. Someone who had never been to the UK, and had no knowledge of the traffic
system of this country just couldn’t work out a priori that we have some circular traffic
signs (if you doubt this, try working out, just by thinking about it, what shape the traffic
signs are in Venezuela).
The only way to find out what shape traffic signs are in a particular country is empirically.
We need to carry out what Hume calls ‘enquiry’. That is, we need to observe – go and
have a look at traffic signs, or ask someone who has done this and is therefore a reliable
authority, or check in an authoritative book such as the Highway Code, and so on.
Note how we can tell, just by thinking about it, that Venezuela does not have traffic signs
which are both circular and triangular at the same time. That is necessarily the case (it is
a relation of ideas).
Note also that if Venezuela does not have circular traffic signs, we can say that it could
have had them (contrast: Venezuela could not possibly have signs which were both
circular and triangular at the same time).
The way that we put this point is to say that ‘some traffic signs in the UK are circular’ is a
proposition which is contingently true.
So matters of fact are a posteriori, and contingent. Relations of Ideas are a priori and
necessary.
There is a test for deciding whether any proposition is a relation of ideas or a matter of
fact. Hume points out that:
‘The contrary of every matter of fact is still possible; because it can never imply a
contradiction, and is conceived by the mind with the same facility and distinctness, as if
ever so conformable to reality.’
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What he means by this is that if we take any proposition which is a relation of ideas –
such as ‘no triangles are circular’ – the opposite (‘the contrary’) of this proposition is selfcontradictory:
•
•
‘some triangles are circular’
‘all triangles are circular’.
are propositions which contradict themselves.
Notice how there is also a psychological test. Our minds cannot conceive any object
being both triangular and circular at the same time. A triangular circle is just
inconceivable.
With matters of fact, by contrast, the contrary is not self-contradictory. If we say:
•
‘no traffic signs in the UK are circular’
then we say something that is false – but we have not contradicted ourselves. Because it
is only contingently true that some UK traffic signs are circular, the world could have been
such that no UK traffic signs are circular (that, of course, is why we have to use empirical
means – observation – to find out one way or the other).
Note also that when we come to the psychological criterion – the ‘conceivability in the
mind’ criterion – it is in fact easy to conceive of a situation in which there are no circular
UK traffic signs (where, for example, the Department of Transport redesigns traffic signs,
so that there are no longer any circular signs).
Activity 9
Looking back over the arguments that Hume has presented about the nature of
knowledge, where do you think we now stand? Has Hume persuaded us that innate
knowledge does not exist? Do we better understand how our minds work on sensory
information to create complex ideas? Hume has argued that there are no ideas without
impressions – is he correct? Look back over your notes and try to summarise where we
have go to, then try to give your view about his arguments.
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Habits of Thinking
When Hume turned to considering the meaning of some phrases, terms and statements
used by philosophers, he found that they did not hold up in terms of his own established
rule. Only those ideas that are based upon impressions are real. When he considered
certain statements in the light of that rule, he found that they simply evaporated. What did
it mean for example, to claim as some philosophers had – that there was a ‘substance’
within things that was essential to them, when there was no impression upon which to
base this claim?
Now that might mean that all sorts of statements and terms used by philosophers could
be called into question – but that was not a terribly important matter after all philosophers
had been arguing about such matters for a very long time. However there are other
important implications that arise from this perspective. For example what did it mean to
state that one thing ‘caused’ another? Was there an impression upon which the idea of
cause was based?
In a famous discussion Hume offers us the example of a billiard table. Billiards were very
popular and fashionable during Hume’s lifetime. Think of the simple process – the cue
strikes the white ball, it rolls across the table and strikes a red ball and the red ball rolls in
turn off towards a pocket. We would happily say that the reason for the movement of the
red ball was the impact it took from the white ball. Being struck caused the red ball to
move.
In order to explore this Hume invites us to think in strict empirical terms. What can we
record about these events as impressions? In the first case in order for these events to
take place, the red and the white ball need to be close to each other, they have to occupy
more-or-less the same space. They both need to be on the same table. So first of all we
can record that we need a relationship in space between the objects concerned and that
is something we can note and understand as an impression. Secondly one ball has to
move first, the other second, so we also need a relationship in time. Again this is
something we can observe and note – it is empirically established.
If we now want to claim that the movement of the red ball caused the movement of the
white, we are in some degree of trouble. In effect when we observe a chain of events
such watching one billiard ball strike another we want to identify three sets of relations.
1. Relations in space.
2. Relations in time.
3. A necessary connection or relation between one thing and another.
The first two we can demonstrate empirically, we can observe the relations in time and
space. The last however we cannot observe empirically – or to put it in Hume’s terms –
there is no impression to support this idea.
That being the case, and using the rule that Hume has established, if there is no
impression, then there is no reality to the idea. Hume has undermined the whole idea of
causality.
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Think of it another way. We put the key in the car’s ignition and turn it on. Each time we
do this there is a clearly perceivable set of processes involving relations in time and
space. When we turn the key can we know that the car will start? Again the answer has to
be no. There is no impression that tells us that events in the past prove what will happen
in the future. Perhaps for the most part the car does start, but sometimes it does not –
and since there is no necessary connection between events in the past and events in the
future we should in a sense be as surprised when it does start, as we sometimes are
when it does not!
The fact that we are surprised perhaps indicates something important about how we
think. We like to imagine that our world works in a predictable way, we like to think that
we know that events are tied together by cause and effect, but in truth these are – what
Hume describes as – merely habits of thinking.
You may be familiar, if you have studied Psychology, with the famous experiment usually
referred to as ‘Pavlov’s Dogs’. The Soviet scientist Pavlov showed that he could – by
repetition and custom – establish a pattern of behaviour in dogs. Each time the dogs were
fed a bell was rung. After some repetition of this practice, the bell only had to be rung for
the dogs to salivate in anticipation.
Did the bell ‘cause’ the food to appear? Clearly not – but the repetition of the practice had
established for the dogs a pattern, a sequence of event. The two things occurred
together, the ringing of the bell and the provision of food. This is just like – in a sense –
the repeated experience of turning the key in the ignition and starting the car. In both
cases a set of things occur together, which we associate. Or as Hume puts it we establish
in our minds a ‘constant conjunction’ and having established this we expect the same
pattern to repeat under the same or at least similar conditions. However we have no
evidence, no empirical basis for thinking in that way all we have is a habit of thinking
acquired over time – just like Pavlov’s dogs although in the case of the dogs it is unlikely
that they assume that this proves that cause effect is involved!
Activity 10
Summarise in your own words the problem that Hume has identified with the idea of
causality.
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The Problem of Induction
The Princess (Robin Wright) in Rob Reiner’s (film) The Princess Bride (1987) is sure that
she and her dashing rescuer Westly (Cary Elwes), on the run from the unpleasant Prince,
will never survive the dreaded Fire Swamp. But Westly’s response shows the right degree
of caution about inductive inferences, no matter how strongly based: ‘Nonsense, you’re
only saying that because no one ever has.’
Philosophy Goes to the Movies
Christopher Falzon (Routledge 2002)
This is what has come to be called the Problem of Induction. Induction is the process of
reasoning from past examples, because we know, or rather assume, that fire is hot, we
do not put our hands into the flames. Past experience has taught us this and from that
past experience we reason that under similar conditions, the same things will occur, that
is induction. Importantly induction is a key element of scientific reasoning. Whenever we
carry out an experiment in science we are operating inductively, we are assuming that
what is true for one experiment in the past will hold true for other experiments in the
future. Hume however has posed a real problem here, science is based on learning from
experience, in other words it is empirical, Hume has taken that empiricism to its logical
conclusion to the point where it becomes clear that inductive reasoning does not stand up
to an empirical analysis.
Hume gives a further clear argument to support the idea that we are creatures that
depend upon habits of thinking. If we were to compare the behaviour of people to that of
animals – what lessons could be learned?
In the first case, is it not the case that in many respects the behaviour of an animal and
that of a person will be remarkably similar? For example a dog will seek to avoid being
burnt by a fire as much as a person would. If a dog comes upon a precipice it backs away
– just a person would. People and animals tend to avoid pain and seek out pleasure. That
being the case why should we assume that the reasoning of animals is in this at least,
any different from our own?
This must make us conclude that arguments about the special nature of the human mind
are less than convincing. For much of the time, humans would do little different from
animals, and so for the most part the operations of the animal mind and the human mind
must be very similar. Animals will base their actions and reasoning upon impressions –
just as we do. Repeated or customary events in the life of the dog will set up customary
practices and behaviours. By the same token our beliefs as to the nature of our life
cannot be immune to effects of custom. The dog hears its master call it to be fed; does it
construe from this cause and effect? Does it believe that there is a necessary connection
between being called and being fed? No – it simply acts on the basis that that is what
usually happens. We on the other hand have sets of events in our lives that seem to
repeat and we behave accordingly. Custom and practice lay down patterns for our life.
But that does not mean that we can leap to the conclusion that something else we call
‘cause and effect’ is involved. Habits of thinking are part of our nature.
In effect then Hume has given us two strong arguments against induction. One
psychological – we mistake constant conjunction for cause and effect because it suits our
habits of thinking – and one logical – for induction to work there would need to be a
necessary connection between things that does not in fact exist.
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One way of understanding this argument is to take the view that Hume has thoroughly
undermined the basis of science and has a very strange view of the world. He seems to
live in a world where cause and effect does not work and nothing we have done in the
past establishes what will happen in the future. How does he live and work if that is the
case? In fact of course, Hume behaved as we all do as if experiences in our past told us
what would happen in the future. He did not have to put his hand into the fire every time
he saw a fire in order to be sure that it would burn him!
So another way of understanding his argument is to appreciate that he is saying that this
is the reality of where we are. We operate by these ‘habits of thinking’ and that is what we
must do. Hume himself seemed to swing between a rather depressed view that
whenever we tried to establish our habits on a more sure foundation we were doomed to
failure to a rather carefree view that – well, at the end of the day we had no option really
but to carry on as if our habits of thinking were absolutely right and fine, so why worry?
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Critical Evaluation of Hume
Hume has presented us with a strongly-argued and challenging set of views. We began
by establishing the basis of Hume’s empiricism.
Summary:
1. The argument about ideas and impressions provided us with the rule that there are no
ideas without impressions – which flatly contradicted the Rationalist argument that some
knowledge was innate.
2. He then made a distinction between impressions and ideas based upon their impact
upon us. Impressions he argued were immediate, vivid, lively in ways that ideas in the
mind could not be.
3. In order to explain some elements of the working of the human mind, Hume explored
the workings of the imagination. He argued that the imagination worked by:
•
•
•
•
compounding
transposing
augmenting
diminishing.
This led to distinguishing between simple ideas – directly recorded from impressions, and
complex ideas which were created out of simple ideas by the working of the imagination.
So it is possible for us to imagine a gold mountain – or a unicorn – because the
imagination works on ideas to compound and create these notions.
4. He went on to refine this argument yet further by suggesting that some ideas were
based on impressions from outside of ourselves, but that others could arise from our
internal sentiments – or feelings.
5. In the midst of this argument he mentioned the problem of the Missing Shade Blue –
but dismissed it as a minor difficulty not worth worrying about!
6. He argued that if someone had never experienced a particular form of sensory
experience – if someone had never seen colour for example – then they could not form
any corresponding ideas that depended upon that experience. Further support to the
argument that all ideas are based on impressions.
7. Hume’s fork. Hume suggested that knowledge split or divided (hence the idea of a
fork’) into two forms, Matters of Fact and Relations of Ideas. He used the term a priori to
mean relations of ideas, and a posteriori to mean Matters of Fact. Relations of ideas
provide certainty because they are either intuitively or demonstrably true. Matters of fact
however are contingency true.
8. Hume then asked us to appreciate that our view of the world is based more upon
habits of thinking than anything real. In his analysis of causality he found that we could
only identify relations in space and time, no necessary connection between things could
be discovered.
9. Furthermore he found that what we think of as causality amounts to no more than a
constant conjunction from which we add a metaphysical concept of causality.
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10. Lastly in the operation of the reason of animals Hume found that much they did was
based on the same impulses of seeking pleasure and avoiding pain that motivated
people. And that custom and habit were also powerful influences upon behaviour for both
animals and people.
Hume is clearly an important philosopher who presents us even today with questions that
are difficult to resolve. But that is not to say that there are no problems with his
arguments.
Problems
In the first case Hume himself provided an example that seemed to contradict his most
basic argument. The Missing Shade Blue that we discussed earlier seemed to contradict
his view that there could be no ideas without impressions. Although we determined that
this might be explained by understanding colour as a complex idea – or at least by
recognising that the categories of ideas – simple and complex – were not mutually
exclusive. But this is not an argument that Hume developed – rather oddly he simply
dismissed the example as a peculiarity.
There are perhaps other difficulties with his argument that might be less easy to deal with.
In the first case are we really happy with his view of impressions and ideas? He seems to
be dealing with both as though there were images – mental pictures that are clear for a
time but then fade. He also argued that the main distinction between actual experiences
and memories or ideas held in the memory was the vividness of experience by
comparison to the weaker impact of either remembered experiences or imagined
experiences. But is that really the case? Do people never have such powerful memories
of events and places that they overcome immediate perceptions?
What about dreams or nightmares? People experience or feel things in dreams and
nightmares that are not based directly on experience – they are imagined into existence
out of the memory but whilst a person is experiencing a powerful dream or nightmare they
can be intensely vivid. Much more so than the impression of being in bed!
Perhaps the central and most important argument raised by Hume is that we refer to as
‘the Problem of Induction’ – although Hume himself never used the term ‘induction’.
Repeated attempts have been made since Hume first published his argument to try to
refute his case. Many philosophers have found that attempts to prove Hume wrong
provided an important stimulus and starting point to their own deliberations. Some have
argued that the whole case is simply misconstrued and that there is no ‘problem of
induction’.
One strong case is that provided by the philosopher Karl Popper. Popper in effect begins
with the view that there is no good reason to dispute the common-sense observation that
the world is real and perceivable. That being the case we can put to one side any
extreme or wild attempts to deal with Hume’s critique by calling into question the nature of
existence. Having established that, Popper then takes the view that Hume is right – up to
a point. There is, or at least would be a problem of induction if that really was the basis for
scientific knowledge or for that matter of our common understanding of how the world
works.
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In Popper’s view Hume in effect has a view of science that is based on a fairly basic
understanding of its processes. After all science as a project was very much in its infancy
in Hume’s time. We can see with our longer perspective that science is no about
establishing firm truths on the basis of induction. Scientists do not in fact conduct series
of experiments with the view of inducing from them general rules that tell us how things
will behave in the future. Instead scientists are generally very well aware that each
proposition that is put forward will only hold up until some way of disproving it is found. Or
as Popper put it – scientist only construct conjectures about the nature of things.
So when we go to the car, put the key in the ignition and turn it, we are really waiting to
see what will happen, rather than operating on the assumption that since the car started
successfully when we did this before, it will always do so. In truth we know fine well that
we are working with assumptions, with guesses that can prove to be wrong when we
induce, when we move from events we have experienced in the past to events in the
future. We can re-state Hume’s argument like this:
1. Any event will involve relations in space.
2. Any event will involve relations in time.
3. We can, by trial and error, try to discover if what occurred in the past leads to what will
happen in the future.
Step 3 is not about induction; it is about trying this out with the understanding that we are
not expecting or relying upon a necessary connection between events in the past and
events in the future.
So we might argue that the logical argument that Hume presents, that there is no
necessary connection between what happened in the past and what will happen in the
future is correct – it’s just that as it happens that is not really how science works – nor is it
altogether true of how we think. Instead we should understand scientific propositions as
attempts at finding answers with the clear understanding behind them that they may well
and often are falsified – shown to be wrong, and that is not a problem but actually part of
the nature of the scientific process itself.
The psychological problem, that people’s habits of thinking lead us to induce from
repeated past experiences what will happen in the future, can be dealt with in the same
manner. Is it really unreasonable to make suppositions about the future on the basis of
repeated examples when we know that what we are doing is making guesses – educated
perhaps – but guesses nonetheless? In effect we are trying out things, we are testing to
see if the repeated examples of events from the past does in fact hold true for our current
experience. We put the key in the ignition and we try turning it to see if indeed the car
does start.
Perhaps one of the dangers here is that we get lost in a maze of words that attempt to
capture the real complexity of the world and our experience in a form that gives rise to its
own set of complications.
In any case Hume remains as a towering figure. A brilliant and very clever man, who was
liked by his contemporaries, was sociable and friendly, often quiet in the company of
people that his intellect could have daunted, and known as a person of virtue and goodnature. It remains as a testament to his intellect that philosophers to this day argue about
his views, and that many important philosophers that followed after him, owed much to
his insights.
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