PH2206GEK,
Founders of Modern
Lecture 1
Modern European Philosophy:
Rationalism Versus Empiricism
Assoc. Prof. John Holbo
phihjc@nus.edu.sg
Warning:
‘Modern’ means different things to different people.
Modern history
Modern art
Modern rock
Modern life
Modern love
Modernity
Postmodernity
Modern, modern, modern, modern. Say it too many
times, the word starts to lose all meaning.
René Descartes (1596-1650)
Discourse on the Method (1637)
Meditations on First Philosophy (1641)
Baruch (or Bernard) Spinoza (1634-1677)
Tractatus Theologico-Politicus (1670)
Ethics (1673)
John Locke (1632-1704)
Essay Concerning Human Understanding (1690)
Gottfried Leibniz (1646-1716)
Discourse on Metaphysics (1686)
Monadology (1714)
George Berkeley (1685-1753)
A Treatise Concerning the Principles of Human Knowledge
(1710)
Three Dialogues between Hylas and Philonous (1713)
David Hume (1711-1776)
Treatise of Human Nature (1739)
An Enquiry Concerning Human Understanding (1748)
Immanuel Kant (1724-1804)
Critique of Pure Reason (1781)
Prolegomena to Any Future Metaphysics (1783)
Modern
European
Philosophy
Rationalism
Descartes
(1641)
Empiricism
Spinoza (1665)
Leibniz (1685)
Locke (1689)
Berkeley (1710)
Hume (1739)
Kant
I. Presocratic Philosophy 600-500 BC
II. Golden Age of Greek Philosophy: 450-350 BC: Plato &
Aristotle
III. Hellenistic Philosophy: 300 BC - 300 AD
IV. Early Christian Philosophy): 300-450 AD: Augustine
V. The Dark Ages 400-800 AD
VI. Late Medieval Philosophy: 800-1100 AD
VII. High Medieval Philosophy 1100-1350 AD: Aquinas
VIII. Renaissance Philosophy 1350-1550
IX. Modern Philosophy 1550-1870 AD: Descartes
We can think of the history of modern philosophy
(conventionally conceived) as focusing on four basic
questions (and note how much this leaves out, by the by -ethics, politics and so forth):
1
What is the nature of the human subject (the mind)?
[Philosophy of Mind]
2
What is the nature of the world (matter)? [Metaphysics]
3
What is the nature of the relation between mind and
matter, such that the former can know the latter?
[Epistemology]
4 What is the nature of science? [Philosophy of Science]
Science is highly esteemed. Apparently it is a
widely held belief that there is something special
about science and its methods. The naming of
some claim or line of reasoning or piece of
research “scientific” is done in a way that is
intended to imply some kind of merit or special
kind of reliability. But what, if anything, is so
special about science? What is this “scientific
method” that allegedly leads to especially
meritorious or reliable results?
- A.F. Chalmers, What Is This Thing Called
Science?
The first thing you might think to say about the
claims is that they are special because they are
TRUE.
But whatever else may be wrong with this, it isn’t
sufficient.
Socrates: the trouble with true belief is that it may
‘run away’ unless tied down with ‘threads of
memory’.
Do not show me a
general who is good. I
want one who is lucky.
- Napoleon
Do not show me a
scientist who is good. I
want one who is lucky.
- Napoleon
Try again: what makes the claims of science
special is that they are KNOWLEDGE. (Other
stuff is just BELIEF or FAITH. It may be true, but
that will just be luck.)
But what is knowledge? How do you define it?
How can you tell whether you’ve got it?
What a man believes, he thinks he knows. Aristotle
Knowledge = df. justified, true belief.
… but what does ‘justified’ mean?
We proceed to the next key words from the
Chalmers passage: line of reasoning; piece of
research.
Descartes defines knowledge in terms of
doubt. While distinguishing rigorous
knowledge (scientia) and lesser grades
of conviction (persuasio), Descartes
writes …
http://plato.stanford.edu/entries/descartes-epistemology/#1.1
I distinguish the two as follows: there is
conviction when there remains some reason
which might lead us to doubt, but knowledge
is conviction based on a reason so strong that
it can never be shaken by any stronger reason.
- Descartes
Knowledge implies CERTAINTY. (If Descartes is
right.)
But this is ambiguous between a psychological and a
justificatory sense.
I can be certain due to overconfidence. If I’m
overconfident, we think that’s almost the OPPOSITE
of knowing.
We want certainty in the sense of justification.
Also, certainty seems too strong …
Descartes’ Method:
1. Never accept anything doubtful.
2. Divide each difficulty into as many parts as
possible.
3. Conduct my thought in an orderly way.
4. Make complete enumerations and general
reviews.
Like the precepts of
some chemist; take
what you need and do
what you should, and
you will get what you
want.
- G. W. Leibniz
But Descartes’ method isn’t common sense, and it
doesn’t sound like chemistry or any other science
either.
That first step is a doozy:
Never accept anything doubtful.
1) Science is collaborative. Even if you work by
yourself, you consult the works of others. That requires
a degree of trust. Trust is incompatible with doubting
everything.
2) Science is fallible. Every good scientist knows that
any result may be overturned tomorrow by further
evidence.
2) Science is (bit hard to know which term is best)
hypothetical. (Or maybe: probabilistic.) This means it
doesn’t wait around for absolute certainty to arrive
before it moves along.
Why is science fallible and hypothetical (never
mind about collaborative)?
Chalmers suggests we have an intuition that
something like the following might be right:
What is so special about science is that
it is derived from the facts, rather than
being based on personal opinion.
Science is fallible and hypothetical because pesky
new facts may pop up to bother us.
How could Descartes (and Leibniz) get so confused
as even to suggest the contrary?
Let’s start like so: Chalmers goes on to suggest that
‘derived from the fact rather than personal opinions’
is a very problematic formula. Let me approach
Descartes by bringing out how so …
Here’s an EPISTEMOLOGICAL thought. A thought
about the nature of knowledge - about the relation
between mind and reality.
How can it be that mathematics, being
after all a product of human thought
independent of existence, is so admirably
adapted to the objects of reality?
- A. Einstein
Why does this make trouble for ‘facts rather than
opinions’ as a formula for science? Let’s jump back to
1596 …
Let’s read a
bit from …
Johannes Kepler,
Mysterium
Cosmographicum: A
Prodromus to
Cosmographical Treatises,
containing the Cosmic
Mystery of the admirable
proportions between the
Heavenly Orbits and the
true and proper reasons
for their Numbers,
Magnitudes and Periodic
Motions.
Why waste words? Geometry existed before the
Creation, is co-eternal with the mind of God, is
God himself (what exists in God that is not God
himself?); geometry provided God with a model
for the Creation and was implanted into man,
together with God’s own likeness - and not
merely conveyed to his mind through the eyes.
…These figures pleased me because they are
quantities, that is, something which existed
before the skies. For quantities were created at
the beginning, together with substance; but the
sky was only created on the second day …The
ideas of quantities have been and are in God
from eternity, they are God himself; they are
therefore also present as archetypes in all minds
created in God’s likeness. On this point both the
pagan philosophers and the teachers of the
Church agree.
In 1595, while inscribing the following geometrical figure
on the board of his classroom, Johannes Kepler was struck
by an idea.
For years already, he had mulled a question, concerning
the nature of the solar system. Why six planets, “instead
of twenty or a hundred?”
6?
5?
20?
100?
Looking at the lefthand figure on the blackboard
one day, Kepler was struck that the ratios of the
two circles were the same as the orbits of Saturn
and Jupiter.
Saturn and Jupiter are the ‘first’ -- i.e. outermost -planets, and the triangle is the ‘first’ figure in geometry.
(Any figure with fewer sides is a line, after all.)
Next comes Mars. . .
Then Earth. . .
But wait: the universe is three dimensional, not two
dimensional. Furthermore, there are five intervals
between the planets, and five ‘Platonic’ solids. It must
be that these figures will give us the ratio of the orbits.
Start with Saturn (and an orbital sphere of sufficient
thickness)
Insert a cube within that sphere, and a sphere within
that cube, within which Jupiter may safely spin. . .
Repeat procedure with a tetrahedron for Mars. . .
And a dodecahedron for Earth.
An icosahedron between Earth and Venus. . .
Between Venus and Mercury an Octahedron.
Add the sun. . . and we are done!
Within a few days everything fell into its
place. I saw one symmetrical solid after the
other fit so precisely between the appropriate
orbits, that if a peasant were to ask you on
what kind of hook the heavens are fastened
so that they don’t fall down, it will be easy
for thee to answer him. Farewell!
Except it was all totally wrong.
Kepler and Tycho - quarrelsome marriage of theory
and observation.
In science there is only physics; everything
else is stamp collecting. - Ernest
Rutherford
But it took years before Tycho would let Kepler
see his cool stamp collection [I mean his data
set] so he could do some decent physics …
To make a long story short, Kepler went on to
formulate his Three Laws of Planetary Motion:
1. The orbits of the planets are ellipses, with the sun at
one focus.
2. A line joining a planet to the sun sweeps out equal
areas in equal time as the planet orbits.
3. The ratio of the squares of the periods of any two
planets is equal to the ratio of the cubes of their
average distances from the sun.
… And Newton reduced it all to his Universal Law of
Gravitation, and so it goes.
What is striking is role played by luck and also hyperrationality - being too rational for your own good.
Why are there six planets, rather than five or seven?
This is a terrible question to approach purely rationally.
First, it presupposes a falsehood; that there are only six
planets. Second, the explanation for the number of
planets in our or any solar system - even if you get the
number right - turns out to be a matter of messy
empirical details (of stamp collecting, if you will.)
Six is a number perfect in itself, and not because
God created all things in six days; rather the
inverse is true, that God created all things in six
days because the number is perfect [1 + 2 + 3], and
it would remain perfect, even if the work of the six
days did not exist.
- St. Augustine
“When one is only interested in what went on in past
centuries, one usually remains extremely ignorant of what is
happening in this century”
- Rene Descartes, Discourse on the Method
“I am convinced that the most devoted of those who now
follow Aristotle would think themselves happy if they had
as much knowledge of nature as he had, even if it were a
condition that they would never have more. They are like
the ivy which does not seek to climb higher than the trees
which support it, and which even often comes down again
after reaching the top; for it seems to me that those people
come down again, that is to say, become in some ways less
learned than if they abstained from study who, not being
content with knowing all that is intelligibly explained in
their author, wish, in addition, to find in him the solution of
many difficulties of which he says nothing and about which
he perhaps never thought.”
- Descartes, Discourse on the Method
Russell on Leibniz’ philosophy: “an exposition of the
system Leibniz should have written.” This is
ambiguous between an examination of what he actually
did (but imperfectly expressed) and an improvement of
what he did, i.e. Leibniz version 2.0.
So the risk is splitting the difference in an unsatisfactory
way - i.e. by doing semi-falsified history of European
thought while at the same time doing unnecessarilyrestricted philosophy of all the subjects one’s historical
figures are discussing.
To repeat:
1
What is the nature of the human subject (the mind)?
[Philosophy of Mind]
2
What is the nature of the world (matter)? [Metaphysics]
3
What is the nature of the relation between mind and
matter, such that the former can know the latter?
[Epistemology]
4
What is the nature of science? [Philosophy of Science]
Hence the logic behind the act of dividing the history of
modern philosophy into a competition between two basic
epistemological philosophies, i.e. two philosophies of the
nature of knowledge.
To wit: rationalism and empiricism.
Rationalism seems to deny that thing Chalmers said …
The Intuition/Deduction Thesis: Some propositions in a
particular subject area, S, are knowable by us by intuition
alone; still others are knowable by being deduced from intuited
propositions.
The Innate Knowledge Thesis: We have knowledge of some
truths in a particular subject area, S, as part of our rational
nature.
The Innate Concept Thesis: We have some of the concepts we
employ in a particular subject area, S, as part of our rational
nature.
Some (rough and ready) definitions:
“An empiricist will seek to relate the contents of our minds, our
knowledge and beliefs, and their acquisition, to sense-based
experience and observation. He will hold that experience is the
touchstone of truth and meaning, and that we cannot know, or
even sensibly speak of, things which go beyond our experience.
A rationalist, on the other hand, holds that pure reason can be a
source of knowledge and ideas; what we can meaningfully
think about can transcend, and is not limited by, what we have
been given in experience.”
- R. S. Woolhouse, The Empiricists
“Empiricists are like ants; they gather and put to use; but
rationalists are like spiders; they spin threads out of
themselves.” - F. Bacon
“One element in rationalist thought is a certain caution about
the deliverances of the senses, and a belief that the correct use
of reason will enable us to progress beyond the naïve,
commonsense view of the world. Another is the vision of the
universe as an ordered system, every aspect of which is in
principle accessible to the human intellect. A further strand is
a tendency to be impressed by mathematics both in virtue of its
intrinsic clarity and certainty, and also because it is seen as a
model for a well-founded and unified system of knowledge.
And a final element. . . Is the belief in necessary connections in
nature, and more, generally, the view that scientific and
philosophical truth must involve reference to what, in some
sense, cannot be otherwise.” - J. Cottingham, The Rationalists
Putting it another way:
Mathematics most clearly (or most strikingly) exemplifies the
character of a large class of thoughts - ‘pure’ thoughts, or
products of ‘pure’ reason (perhaps); a priori knowledge; logical
knowledge; conceptual truths:
For example:
1. Space is three dimensional.
2. All bachelors are unmarried.
3. If Sam is six feet tall, then he is at least five feet tall.
4. If the ball is red all over, then it is not also green all over.
5. Nothing comes from nothing (everything has a cause).
6. Nothing happens without a reason.
The Pedestrian’s Problem
Entry
Entry
Connector
Exit
Exit
The Boatman’s Problem
Entry
Exit
Connector
Entry
Exit
This dispute is not really
modern at all, but ancient
and venerable indeed.
Just Plato versus Aristotle
(courtesy of Raphael).
W. B. Coleridge:
“Every man is born an Aristotelian or a Platonist. They are the
two classes of men, besides which it is next to impossible to
conceive a third.”
Well, actually. . . Conceiving of the third class of men (and
women: let’s be fair here) is really the task of figuring out what
modern science is all about. Both mathematical and empirical.
A passage from Anthony Kenny’s, A Brief History of Western
Philosophy, on Aristotle’s views of science and explanation.
“Science begins with observation. In the course of our lives we
notice things through our senses, we remember them, we build up
a body of experience. Our concepts are drawn from our
experience, and in science observation has the primacy over
theory. . .
“The great book of the Universe cannot be understood unless one
can read the language in which it is written - the language of
mathematics.” - Galileo
The Argument by Skeptical Hypothesis:
Let H by some extreme (Matrix-like) skeptical Hypothesis.
Let O be some rather Ordinary thing you think you know. (I
have a hand in front of my face.)
Now the argument:
P1
I don't know that not-H.
P2
If I don't know that not-H, I don't know that O.
C
I don't know that O.
From de Rose:
http://pantheon.yale.edu/%7Ekd47/responding.htm
Let me make this painfully
obvious:
Let P be: ‘Miss Scarlet did it
in the Lounge with the Knife.
In order to know the truth of P,
we need to know the
falsehood of Q, R and S.
Then Q will be: ‘Col.
Mustard did it in the
Library with the Lead
Pipe.’
And R will we: ‘Mr.
Green did it in the
Ballroom with the
candlestick.’
And S will be: ‘Prof. Plum
did it in the study with the
revolver.
In order to know whodunnit,
where, and with what, you’ve
got to eliminate all the
alternative possibilities.
As any eight year old child will
tell you: if you card looks like
this, you don’t know whodunnit,
where, and with what.