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?

1. SCEPTICISM, SOLIPSISM AND THE VEIL

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

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

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!

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.

2. GENERAL IDEAS

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…

2. GENERAL IDEAS

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

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

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

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

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

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

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.

Can I form an idea of God from experience? Surely God is beyond experience. He is

omnipotent, omniscient, transcendent, and so on.

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.

3. COMPLEX IDEAS: GOD

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: GOD

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.

3. COMPLEX IDEAS: I

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: HUME’S MISSING SHADE OF BLUE

3. SIMPLE IDEAS: SHAPES AND SHADES

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.

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: SHAPES AND SHADES

3. SIMPLE IDEAS – HOW MANY SHADES?

3. SIMPLE IDEAS: COLOURSMagenta, Fuschia, Cerise, Scarlet, Cherry and Burgundy – which is which?

3. SIMPLE IDEAS: COLOURSMagenta, Fuschia, Cerise, Scarlet, Cherry and Burgundy – which is which?

Fuschia Cerise Cherry

Magenta Scarlet Burgundy

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?

3. SIMPLE IDEAS: SPECKLED HEN

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

Mathematics. 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

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

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

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… …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

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: 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.)

5. CHOMSKY AND INNATENESS