Thursday, June 30, 2011

Qualia and the private language argument

To: Tom M.
From: Geoffrey Klempner
Subject: Qualia and the private language argument
Date: 9 July 2003 11:15

Dear Tom,

Thank you for your email of 28 June, with your fourth essay for the Philosophy of Mind program, in response to the question:

'But in the present case I have no criterion of correctness. One would like to say: whatever is going to seem right to me is right, and that only means here we cannot talk about "right"' (Philosophical Investigations Para 258). How effective, in your view, is Wittgenstein's Private language argument in attacking the notion of a 'quale'?

I mostly agree with what you say here, but there are some issues to discuss.

The first concerns the example of measuring blood pressure. I think you have missed the point Wittgenstein is making here. Let's quote the relevant extract from the paragraph (270) in Philosophical Investigations:

"Let us now imagine a use for the entry of the sign "S"" in my diary. I discover that whenever I have a particular sensation a manometer shows that my blood-pressure rises. So I shall be able to say that my blood-pressure is rising without using any apparatus. This is a useful result. And now it seems quite indifferent whether I have recognized the sensation *right* or not. Let us suppose I regularly identify it wrong, it does not matter in the least..."

Wittgenstein is happy to allow that we *can* introduce a term into the language, let's call it 'hypey'. Let's say that Doctors in Sheffield treating patients with chronic high blood pressure have discovered that patients are able to tell by introspection when their blood pressure is rising. Each patient is given a little kit, and told to measure their blood pressure every time they feel a bit 'hypey'. After a while, patients get very expert in making accurate judgements about their blood pressure. What is happening here? If you have never suffered high blood pressure then with regard to the term hypey you are like someone who is colour blind, aware that a distinction is being made, but unable to participate in the 'language game' with the relevant term.

'Hypey' is not a term in a private language. It is a perceptual term, like 'red' or 'tingle' or 'clang' which has a definition (remember that crucial fact about a term from a private language is that it cannot be 'defined').

If one of the patients said, "I know that I'm getting very good at judging my blood pressure", but I'm still not sure whether I'm correctly identifying that hypey feeling," that would be just like someone saying, "I know that I am good at judging when something is blue or not, but I'm still not sure whether I'm correct in identifying my subjective impression of blue."

There is a possible pathological state where a patient who was perfectly competent in making colour judgements suffered persistent doubts about their ability to identify colours, or about the constancy of their inner impressions. But the existence of such a state would not yet be evidence in favour of qualia. (This is relevant to the spectrum inversion thought experiment.)

Similarly, the response to what you say in your e-mail about fish in dentist's waiting rooms is that what we are talking about are peoples *feelings*, and these can be talked about precisely because they are associated with causes and effects, like blue or hypey. Feelings are not qualia, because (if you agree with the anti-qualia argument) there are no qualia. The concept 'quale' is a logically incoherent concept.

Near the beginning of your essay you say that there are two ways to judge the concept of 'quale':

1. Do statements about this concept have a truth value?

2. What consequences or potential consequences flow from its existence or non-existence?

It is important to see that 1. is not verificationism. Consider a statement about the past, 'A tree stood on this spot one million years ago.' An anti-verificationist would agree that the statement can be true even if it is unverifiable. Wittgenstein is arguing that statements about qualia cannot be true, and not merely that the cannot be verified. (If you look through the literature on the PLA, however, you will find that this claim has been disputed.)

Because you were misled by the manometer example, you seem to want to say that the existence or non-existence of qualia can have consequences (e.g. the blood pressure reading) even though true statements cannot be made about them. I hope you can now see that the possibility of making true statements and the possibility of their being consequences (verifiable or not!) go together. One of the essential aspects of truth is that a true statement can stand as the antecedent of a conditional statement. I.e. we can meaningfully say that statement 'P' has a truth value (true or false) if, and only if we can meaningfully say, 'If P then Q' for some statement 'Q' which can be meaningfully said to have a truth value.

All the best,

Geoffrey