SOME PROBLEMS FOR EMPIRICISM
John Locke (1642-1704)
George Berkeley (1685-1753)
David Hume (1711-1776)
THE PROBLEMS
1. The veil of perception: ideas cut me off from
reality.
 2. General ideas: how can a general concept be
represented by a particular sensory idea?
 3. Complex ideas: how can we represent
concepts such as on, not, God, and I?
 4. Simple ideas: how do we tell whether an idea
is simple or complex?
 5. No blank slate: don’t our common
understanding of maths and language prove we
can’t be born blank slates?
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1. SCEPTICISM, SOLIPSISM AND THE VEIL
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If all that is present to my mind are ideas, then
how can I know that they are copies of or caused
by things in the world beyond? If I can’t know
(e.g.) that my idea of a tomato is caused by one, I
can’t know anything about the external world.
We have a problem of scepticism.
1. SCEPTICISM, SOLIPSISM AND THE VEIL
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To confirm whether A represents B, I must be
able to compare A and B. Consider checking
whether a picture represents a person. But if all I
can experience are my ideas, I can’t get ‘beyond’
them to check whether they correspond to the
world. I am trapped in a world of my ideas and
the sceptical problem is insoluble.
1. SCEPTICISM, SOLIPSISM AND THE VEIL
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It gets worse. What is to say that there is no
external world and that all my ideas are
generated by mind. My mind is all there is. We
have a problem of solipsism.
2. GENERAL IDEAS
How do I represent the general idea of a triangle?
Locke said that we abstract away from the
features of specific triangles. But if ideas are
sensory in nature – images, sounds, etc. – as
Locke says they are – then my idea of a
triangle must be (e.g.) an image.
 Berkeley pointed out that triangles are
equilateral or isosceles or scalene. But no picture
can represent a triangle that is not one of these
in particular. It is impossible to paint a general
triangle!
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2. GENERAL IDEAS
Similarly, a cat has no particular colour: cats can
be black or white or tabby.
 But any picture of a cat must give it a particular
colour.
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2. GENERAL IDEAS
Hume argued that we use particular ideas as
general ideas. In my mind, I represent a triangle
with this particular one:
 But when I think of triangles in general, I bring
this to mind but understand anything similar to
this.
 A problem is: how do we represent similarity?
Everything is similar to everything else! A
badger represents a biscuit: both are material,
typically weight under a ton, can’t speak
Japanese…
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2. GENERAL IDEAS
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By triangle, I must understand
and anything that
resembles this in having three straight lines and three internal
angles.
But to understand this, I must have the idea of line. But lines
come in lots of varieties too:
So, to have a general idea of a line I must, in the same way,
have a particular line in mind
and understand that a
line is anything similar to it.
But since everything is similar to everything else, I must
understand that a line is everything similar to my line
in some ways not others.
So, to explain the general idea of a triangle, we have ended up
having to define the general idea of a line! We have exactly the
same problem!
2. GENERAL IDEAS
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A line is the shortest distance between any two
points. So, a line is anything that resembles
(my line) in that way: not colour, or anything else, but
only in being made out of two points joined in the
shortest way.
But now I need to explain my general idea of a point!
We have the same problem all over again!
Ultimately, the Empiricist has to say that we are
simply built to associate certain simple ideas with one
another. We simply see lines
as of the same kind and group them together. Or,
perhaps, triangles. Or, perhaps faces. Who knows?
Does this mean we have an innate idea of line? No!,
they say. We simply have the innate capacity to form
the idea of a line – something really simple – given
the appropriate experiences.
3. COMPLEX IDEAS: ON AND UNDER
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How do I represent on in an image? What about this:
a rat on a cat?
This won’t work. For it is also a picture of a rat under
a cat.
Any picture of A on B is a picture of B under A. We
understand on and under as two different concepts.
So, these concepts can’t be conveyed via images
(sounds, smells…). But this is all the Empiricist has.
3. COMPLEX IDEAS: LEFT AND RIGHT
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The same goes for left and right: if A is to the left of B, B is
to the right of A. What about just having an arrow?
This won’t work. We understand this to mean right. But
someone could understand it to mean left. They think the
straight line, not the head, points in the relevant direction.
We can’t teach someone that they’re wrong by drawing
more and more arrows! Understanding left and right can’t
consist in understanding images.
3. COMPLEX IDEAS: LEFT AND RIGHT
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Nor with it help to show (e.g.) a film of a badger
walking from left to right.
For a film is just a series of pictures. Someone
could interpret the motion left-to-right as the
sign of moving right to left.
3. COMPLEX IDEAS: LOVE
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Another tricky concept is love. Suppose I have the following idea:
Does this represent Gunther loves Rachel or Rachel loves Gunther?
We can’t say: it doesn’t matter. Love is an asymmetric relation – just
because A loves B, doesn’t mean B loves A!
We can’t add an arrow to the heart – we’ve seen that they don’t
convey direction alone.
Nor can we say Gunther is to the left, so he is the subject, as in the
sentence “Gunther loves Rachel”. For in some languages, you can put
the subject last. E.g. in Polish, I can say it by saying “Rachel kocha
Gunther.”
Nor can we appeal to the ‘natural’ way of reading from left to right, to
say that Gunther must be the ‘lover’. For (e.g.) in Arabic, one writes
from right to left.
3. COMPLEX IDEAS: NOT
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Anther problematic ideas is not. How do I paint
a picture of negation? I can’t just have a black
square. This could be a picture of night or
darkness.
Nor can I have picture such as
or
These could equally be ideas of a barred circle or
a cross.
 Other tricky logical words are: and, if, or.

3. COMPLEX IDEAS: GOD
Can I form an idea of God from experience?
 Surely God is beyond experience. He is
omnipotent, omniscient, transcendent, and so on.
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He is not something I can experience with my
senses.
3. COMPLEX IDEAS: GOD
But perhaps I can form the idea of God by
extrapolating from ideas I have. I know powerful
people: I ‘maximise’ the idea of power.
 Similarly, I maximise the ideas of knowledge and
benevolence.
 But is this really the idea of God? Certainly it is
the idea of a God in some religions: e.g. Zeus.
 If you think that God is not like an exaggerated
human, then you might wonder whether it is a
meaningful idea after all.
 It is not as if the idea of an infinite God is
without puzzles.
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3. COMPLEX IDEAS: GOD
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If God is omnipotent, can he create a stone so heavy
he can’t lift it?
If he can, then there’s something he can’t do: lift it.
If he can’t, then there’s something he can’t do: create
it.
Either way, omnipotence leads to paradox!
3. COMPLEX IDEAS: I
Descartes said cogito, ergo sum.
 What am I? I am a mind. I am that consciousness
that in some sense ‘occupies’ my body.
 Descartes says I have an innate idea of a mind
as a ‘thinking thing’: a conscious entity.
 I don’t learn it from experience.
 How could I? I can’t see myself (as a mind) in the
mirror. I can’t, as Hume said, introspect and see
myself. All I ‘see’ when I introspect are ideas
(thoughts).

3. COMPLEX IDEAS: I
Is there therefore an innate idea of self?
 Hume said: no. I can’t find myself by
extrospection or introspection as there is nothing
there to find!
 There are just ideas. The notion of a self is a
fiction. Very roughly, the story is this. There is
just a stream of thoughts that is me. Some
thoughts trigger memories of others. From this,
the idea is created of a ‘me’ that was there then
and here now. My impersonal stream of thoughts
generates the idea of a personal self. But it no
more real than the equator.
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3. SIMPLE IDEAS: HUME’S MISSING SHADE OF BLUE
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Hume said all ideas are ultimately copies of
impressions. But he also said that we can see a series
of blues and imagine – form an idea – of the missing
one! This seems contradictory
What Hume probably mean is that, to form an idea,
you need a corresponding impression of that thing or
of other similar things from which you can
extrapolate.
So, I can form the idea of the missing shade of blue
but someone who has never eaten meat could not
form an idea of the taste of turkey. They have not
similar ideas from which to work.
3. SIMPLE IDEAS: SHAPES AND SHADES
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How do we count simple ideas? How many are there here:
Is this one shape and four rotations? Or four different shapes?
And is this a slightly-different banana a different simple idea of
banana shape?
How are we to count simple shapes?
We can’t say: they are all banana-shaped until we have learned
the concept of a banana.
3. SIMPLE IDEAS: SHAPES AND SHADES
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How many shades are there here?
If X and Y are distinct simple ideas, then I should be able
to tell this without fail – I can’t be wrong about my
simplest ideas!
Yet we can easily be uncertain whether two shades of
colour are the same or different. Or two sounds. Or two
smells.
3. SIMPLE IDEAS – HOW MANY SHADES?
3. SIMPLE IDEAS: COLOURS
Magenta, Fuschia, Cerise, Scarlet, Cherry and Burgundy – which is which?
3. SIMPLE IDEAS: COLOURS
Magenta, Fuschia, Cerise, Scarlet, Cherry and Burgundy – which is which?
Fuschia
Cerise
Cherry
Magenta
Scarlet
Burgundy
3. SIMPLE IDEAS: SPECKLED HEN
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How many speckles does this hen have? We can’t see a
definite number. But it has a definite number.
An idea is a definite thing: it is a complete bit of my mind.
How then can it appear to me in an indefinite way?
5. LEIBNIZ AND INNATE IDEAS
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Locke argued that there was no evidence for innate ideas.
People both fail to show understanding of supposedly
innate ideas (e.g. mathematical ones) and end up with
different ideas (e.g. God, good), presumably because they
have different experiences.
Leibniz argued that Locke was right to point out that ideas
were not fully formed in us at birth but were potentially
there, like Hercules in the block of marble.
For Locke, the mind is a block of marble that can be carved
any way. For Leibniz, the marble can only be carved in
certain ways as there are veins running through it that will
cause the marble to fall away in certain ways as it is
sculpted by experience.
What evidence is there for the latter?
5. LEIBNIZ AND INNATE IDEAS
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Mathematics.
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Firstly, we all end up – converge – on the same mathematical
ideas if we turn our minds to maths. (‘Savages’ may never bother
to do so.)
Secondly, mathematical truths are necessary truths. But we can’t
learn necessary truths from experience. I see the sun rise every
day but that doesn’t prove it must rise tomorrow. Yet I do believe
that 1+1=2 must be true tomorrow.
Third, even if we could ‘experience’ some numbers, such as 1 and
2 (one cloud, two badgers), we can’t experience -7, 1,000,000 or π.
Together, these suggest that we have in us the same
mathematical ideas waiting to be developed.
What can the Empiricist say back?
5. LEIBNIZ AND INNATE IDEAS
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The Empiricist needs to say:
First, we gain simple mathematical ideas from experience.
We see two badgers, two trees, two chickens…we have the
idea of 2!
Second, once we have simple ideas in our heads, we can see
that there are necessary connections between them. Just as
we see that a triangle must have three sides when we learn
that idea from experience, so too do we see that 1+1 must
equal 2.
Third, with the basic ideas of 1 and 2, we can generate the
ideas of other numbers: 3, 4, 5, … and so on.
5. LEIBNIZ AND INNATE IDEAS
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The Empiricist needs to say:
First, we gain simple mathematical ideas from experience.
We see two badgers, two trees, two chickens…we have the
idea of 2!
Second, once we have simple ideas in our heads, we can see
that there are necessary connections between them. Just as
we see that a triangle must have three sides when we learn
that idea from experience, so too do we see that 1+1 must
equal 2.
Third, with the basic ideas of 1 and 2, we can generate the
ideas of other numbers: 3, 4, 5, … and so on.
5. CHOMSKY AND INNATENESS
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Noam Chomsky argued that we cannot be born blank slates
when it comes to language. His argument is known as (or
as a type of) Poverty of Stimulus argument:
Children learn language…
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…too quickly…
…on the basis of too little data…
…given their intellectual limitations…
…to suppose that they do it all from scratch.
This doesn’t mean children are born knowing a particular
language.
Rather, children must be born with an innate knowledge of
the underlying grammar of all possible human languages.
5. CHOMSKY AND INNATENESS
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Does this mean we have innate ideas of grammatical
concepts? Or innate knowledge of the rules of grammar?
Chomsky said: not exactly.
Traditionally, innate ideas and innate knowledge are
things that can be brought to mind: we can come
consciously to grasp and understand them:
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God is omnipotent.
2+2=4
But we cannot become conscious of the rules of grammar.
(Which is not to say we can’t work them out. We can’t
become conscious of the structure of the neurons that make
up our brain but we can use science to investigate them.
Investigating the structure of language is the business of
linguistics.)