Friday, March 8, 2013

On the veil of perception problem

To: Manuel R.
From: Geoffrey Klempner
Subject: On the veil of perception problem
Date: 3rd June 2009 11:38

Dear Manuel,

Thank you for your email of 19 May, with your essay towards the Associate Award, entitled, 'On the 'Veil of Perception' Problem'.

In response to your 'two answers' to my comments on your previous essay:

1. Aristotle's conception of explanation in terms of formal causes led him to reject any claims that the processes observed in nature, e.g. freezing of water or melting of ice, have an explanation in terms of the micro-structural properties of matter, such as the atomists Leucippus and Democritus hypothesized. His view was that human reason together with human powers of observation ought to be sufficient for knowledge of the physical universe. He could not have been more wrong. We do not -- as matter of fact amply demonstrated by modern physics, chemistry and biology -- live in an Aristotelian universe. Water does not freeze because it has the 'freezing power', an more than Aspirin works because it has 'pain killing power'. It was Aristotle who left things 'half explained'.

2. I don't conceive of a 'recognitional capacity' along idealist lines. To exhibit a recognitional capacity is to 'follow a rule' in Wittgenstein's sense, that is to say, a demonstrated practical ability to pick out red objects. I recommend you start with the 'Blue Book' (from the 'The Blue and Brown Books') which includes an excellent critique of Lockean-type views about what it means, e.g., to 'have a concept of red'. (The Blue and Brown Books were originally notes which Wittgenstein dictated to his students at Cambridge.)

The present essay for the most part reads very well.

(A minor quibble, what you term 'induction to the best explanation' would be better expressed as 'inference to the best explanation', what Pierce calls 'abduction' as contrasted with 'induction'.)

My main problem, however, is similar to the one I had last time, namely the role you ascribe to Aristotle's account of perception. We are both agreed that a non-naive 'direct realism' is the view which needs to be opposed to Locke's 'representational realism' in order to resolve the veil of perception problem. However, you give no argument in support of your implied claim that Aristotle's hylomorphism provides the best (or only) philosophical basis for direct realism, or indeed that it is adequate for that purpose.

A little bit of history is needed. According to John Passmore in his excellent book '100 Years of Philosophy', there was a movement in the 1920's called 'new realism'. All of the necessary logical moves needed to combat representationalism were well worked out. One foremost proponent of this view was Samuel Alexander, in his metaphysical treatise, 'Space, Time and Deity'. The main problem with new realism proved to be its ineffectiveness in combating the arguments of the sense datum theorists, which are powerful indeed.

Aristotle isn't tempted by the sense datum theory because in his account of perception there is no way of forming the notion of a 'sense datum'. Aristotle's starting point is an unargued direct realism. I would argue that it is no help enlisting Aristotle in support of direct realism just because he was a direct realist, because the problem we face is finding a satisfactory dialectical response to the arguments of sense datum theorists.

Philosophers who developed an adequate response to the sense datum theory include Moore (in his 'Defence of Common Sense'), J.L. Austin ('Sense and Sensibilia') and L. Wittgenstein ('Philosophical Investigations').

I would not be at all surprised to hear that in the context of these debates, there are aspects of Aristotle's philosophy which are useful and relevant, just as his view of the relation between mind and body is now seen as far superior to Cartesian dualism. However, this is something that needs to be shown.

The main thing that needs to be fixed in my view is the part where you describe direct realism. You need to show more awareness of the main philosophers who have contributed to the downfall of the sense datum theory. Obviously, there is not a lot of space to develop these critiques in detail, but you can indicate the main lines of argument.

The bottom line is this: the 'veil of perception' problem is difficult, possibly impossible to solve. And that's bad. However, it is not enough to point out that a theory X leads to an insoluble difficulty, if we lack the resources for defeating theory X. You show some awareness of this point. However, what you say in support of this claim is unconvincing. I think you could usefully look at the work of 20th century critics of the sense datum theory. Maybe you can even find a way to illuminatingly relate this to Aristotle's view. That would make a very interesting essay.

All the best,