To: Daniel H.
From: Geoffrey Klempner
Subject: Implications of the private language argument
Date: 1 February 2007 10:42

Dear Danny,

Thank you for your email of 24 January, with your second essay for the Philosophy of Language program, in response to the question, 'Discuss the implications of the private language argument.'

This question is primarily about what follows if the private language argument (PLA) is accepted. However, in order to determine just what the PLA claims it is necessary to rehearse the main steps of the argument.

Your essay begins well. You are right to emphasise that Wittgenstein has something very special in mind with the notion of 'privacy'. The essential thing about a private language is that a 'definition' cannot be give of the words in the language; they can only be given meaning through inner 'ostension'; only the person who is in a position to view the 'objects' which the words attach to is able to grasp the meaning.

This is very much how we are tempted to think about our own mental life - as consisting of 'objects' which recur in familiar patterns and combinations. Although aware of the fact that we did not teach ourselves to speak, it does not seem incredible that someone could invent a language whose soul task was to describe one's inner life purely as it appears to the subject alone.

We need to say something more about 'definition'. Wittgenstein means anything at all that would enable one to get an external 'hook' on what the subject is referring to. As an example, he considers the possibility that the subject's blood pressure rises every time he reports an occurrence of S. Now, we have our 'definition'. 'S' is the physical process that occurs which leads to a rise in blood pressure, as well as to the reporting of 'S'. The hypothesis that the language is 'private' rules this out. We are assuming that there is no reliable correlation between the 'inner' and the 'outer', no way to tell whether S is occurring or not other than the subject's ability to recognize S whenever it occurs.

Again, you are correct in describing Wittgenstein's argument about memory. The point here is that in the external world, we are aware of a distinction between 'true' and 'false' memories. Objects and events that we remember leave physical traces; our access to them is not confined essentially to memory alone. Of course, there are many cases where in fact all we have is our memory to go on. I would swear I saw that man before - but there's no way I can prove it. This shows that Wittgenstein's objection is not based on 'verificationism'. He is not saying that all memory claims that cannot be substantiated are meaningless. Rather, the argument is that there can be no coherent concept of a 'reality' where there is no distinction, in principle, between 'true' and 'false' memory.

That is not the whole argument, however. Closely coupled with this is the claim that the name 'S' is not capable of being associated with a 'criterion of identity'. Assume for the moment that memory is not a problem; it remains the case that the subject is free to say when a new object sufficiently 'resembles' the previous object to be called 'S' and when it is sufficiently different to not be called 'S'. In the real world, there are 'rules' which we are able to explain and follow. Correctness or incorrectness in following a rule is not a matter of mere subjective decision but practice.

But what about the implications?

You say that 'Wittgenstein's invention and simultaneous refuting of the argument provides a good platform, essentially that language is a public and socially created concept not held solely in the head of the individual, from which he was able to further expand his ideas of language.'

In other words, the implication of the private language argument is that language is essentially a public phenomenon. This is only the beginning, because we then have to consider what these publicly accessible 'rules' consist in, or what it is that keeps our linguistic usage 'on track'.

However, I want to go back one stage. There is something more immediate, which one could describe as an 'implication' of the PLA.

I remember as a child wondering whether what I see as red other people might see as blue and vice versa, even though we agree on the colour names that we use for things like blood or the sky. One implication - which most find mind-boggling when they first encounter it - is that this speculation is nonsensical. In order to conceive of the possibility that what I see as red you see as blue and vice versa, even though we agree in all our public language colour judgements, it is necessary to coin new terms, 'red GK', 'blue GK', 'red DH', 'blue DH' whose meanings are given purely by ostension, just like the sign 'S'.

If you find yourself wavering at this point, imagine that your 'red DH' and 'blue DH' switch round every second, but you do not notice any change because your memory doesn't record it. This is just a version of the spectrum inversion hypothesis, but substituting 'DH at two different times' for 'DH and GK'.

If you can get over that - and I have to admit that even today my intuitions baulk - then you can see just how profound and indeed shattering the PLA is. Descartes' 'thinking subject' - aware with perfect certainty of itself and its experiences irrespective of whether there exists an objective world or not - is demolished in one fell swoop.

All the best,

Geoffrey