To: Manuel R.
From: Geoffrey Klempner
Subject: Locke on abstraction and the nature of ideas
Date: 15th January 2009 12:04

Dear Manuel,

Thank you for your email of 12 January with your second essay towards the Associate Award entitled, 'Abstraction' and also for your email of 3 December with your first essay, 'On Locke's Treatment of Ideas'. Once again, please accept my apologies for overlooking your first essay in the Christmas rush.

This is good work, which shows evidence that you have really tried to get to grips with Locke. As you remark in your first essay, the most difficult think is grasping how Locke can use the term 'idea' for such disparate things as (what we would now term) a sense datum or perception, or a concept. I say 'sense datum or perception': that distinction in itself raises a huge issue which I shall explain in a minute.

Locke's stated aim, in writing his Essay, is to explain where our ideas come from, how they are formed, and in so doing draw a map of the limits of intelligible discourse. Whenever one cannot say what are the ingredients of an idea -- define it, or explain how it is derived from other ideas -- then we are simply not making sense. He calls his procedure the 'historical plain method'. This genetic view of the formation of ideas would later be criticized by Kant in the Critique of Pure Reason, where Kant argues that certain fundamental ideas or 'categories' are presupposed a priori in forming the very notion of 'objects' of perception.

The main target of Locke's critique are the metaphysical views of notions like 'substance' deriving from the scholastic tradition. (Having just spent the last month working on profiles of the Medieval philosophers for the PhiloSophos 'Philosophical Connections' pages, http://www.philosophos.com/philosophical_connections/ I would say you are a bit harsh on the scholastics, although it is undoubtedly the case that the 'new wave' of philosophers were less interested in the positive achievements of the scholastics.)

Mackie has some interesting things to say about Locke's 'anticipation' of Kripke's ideas on the nature of natural kind terms. Although it is true that Locke is very harsh about the concept of 'substance' as an 'I know not what' underlying the qualities of an object, he does allow a role for the idea of 'real essence' from which the observable properties of an object flow, on the model of Newton's corpuscular theory. Although our understanding of the term 'gold' is given by a 'nominal essence' we recognize that our 'nominal' classifications are not purely arbitrary but rather follow empirical investigation. In that sense, a 'better' nominal idea of gold would be one, e.g. which recognized that a metal can be white yet still be an example of gold.

As you indicate, the main consequence of Locke's use of the term 'idea' for what is given in perception is to 'push the world back' beyond the 'veil of perception'. This is an accusation made generally against all 'sense datum' theories of perception, and implies that for Locke, simple ideas are indeed thought of as sense data.

If that is a mistake, then what would be the correct view? Kant argued that perception is necessarily perception of spatio-temporal particulars. That is to say, it is a priori necessary that our experience has a particular form which makes it possible to apply spatio-temporal concepts to it. 'Intuition' as such (Lockean 'simple ideas') is indescribable except in terms of spatio-temporal concepts. It would be impossible, Kant argues, for a subject to recognize repeatable features -- such as colour, or sound -- in a purely subjective stream of experiences.

For Kant, something is subjectively 'given' but is indescribable as such. Locke's error is in thinking that in using concepts like 'red' we are describing it -- whereas in fact colour concepts like all other concepts only have meaning in relation to a world of spatio-temporal objects. Red, for example, is the colour of tomatoes or blood. Indeed, when Locke gives his theory of 'primary and secondary qualities' much of what he says there is fully consistent with Kant.

Much later, with the philosophy of Wittgenstein, the notion of a 'private object' (Lockean sense datum) would be subjected to even more radical critique, in Wittgenstein's argument against the possibility of a private language.

Which brings us to your second essay, on Abstraction. A good book to read on this issue is 'Mental Acts' by Peter Geach, in the Routledge Library of Philosophy and Psychology. (It is a small, red volume.)

It is in fact the very same error -- the idea that we somehow learn to 'name' the qualities of our subjective experiences or 'private objects' -- which gives rise to the abstractionist theory. Geach argues (on lines not that far removed from the Aristotelian view of concepts which you contrast with Locke) that a subject needs concepts in order to recognize patterns in experience. You can't teach a child the meaning of 'red' and 'round' by showing various red objects and round objects and expect the child to somehow 'intuit' the difference. Before one can form the idea of specific colours or shapes one must have the idea of colour or shape as such: in other words, a complex scheme of concepts is developed through learning to follow the rules for the use of concept words. To take the example of colour, it is impossible to know what red is if you don't know that colours are (e.g.) properties of surfaces, or that colours depend on the quality of reflected or transmitted light. Of course a child does not learn all this at once. The infant who has learned to say 'red' when it sees a red toy has not yet 'got' the concept of red.

I did find both of your essays a little bit unfocused. This is partly the fault of the very general titles (Locke on ideas, Locke on abstraction). What you need to think about are particular issues or arguments. Although it is admirable that you have tried to write a 'friendly' introduction to Locke's philosophy which a beginner could understand, you need also to have a case to make, a particular view that you are arguing for. For example, in the first essay, that view might be related to the critique of Locke's 'veil of perception'. In the second essay, that view might be related to the critique of Locke's account of abstraction. A good way to do this is compose more specific titles which announce to the reader what view of Locke you are arguing for, the case you are trying to make.

Overall, I am very pleased with this effort. Well done!

All the best,

Geoffrey