To: Michael W.
From: Geoffrey Klempner
Subject: 'The world is my world' and solipsism
Date: 6 July 2002 12:52

Dear Mike,

Thank you for your e-mail of 26 June, with your last essay for the Philosophy of Mind program:

'The world is my world' - Explain how the theory of solipsism arises in the context of the mind-body problem. Can the solipsist be refuted?

Well done for completing the program! My report together with a certificate of completion will go out next week.

I am glad that you have enjoyed the course. The Philosophy of Mind program ends with a question which has been with me now for a long time. I doubt whether I shall ever get past it. So I can understand well your feeling of disappointment too.

This a fine, energetic and creative approach to the question of solipsism. This is the first time I have seen the predicament of the solipsist compared with that of the prisoner in Plato's Cave. I liked that a lot.

What do we learn from the thought experiment of Solly, Laura and the VR machine? The hypothesis, and the claim that the hypothesis is irrefutable, is *not* solipsism. I don't believe you think this. Rather, you are using the thought experiment as a way in to the solipsist's metaphysic.

Someone who says that the VR hypothesis is irrefutable is not saying that my subjective world is all that there is. On the contrary, the sceptical threat is real because one accepts without question that this subjective experience has an objective side: the problem is we don't know what this objective side is. (Sorry if I seem to be labouring a point that is obvious to you.)

Within my experience, there is always the empirical possibility of 'waking up' (as in the film 'The Matrix'). There is room for doubt - which can be confirmed, but never assuaged.

What gets the solipsist going is the thought, 'However things turn out empirically, whatever happens to me is merely a story about the my world.' In other words, although one may talk of 'appearance' and 'reality', subjective experience and its objective interpretation, this is all a relative distinction *within* my world - which from an ontological point of view is all there is or could be.

Solly the newly converted solipsist continues to use the language which he 'learned'. The words do not become words for 'private objects' but continue to refer to such mundane things as computers, cars, trees and people. (You don't need to say that there can be thought without words.)

This, I would argue, is the lesson of Kant's 'Refutation of Idealism': 'The empirically determined consciousness of my own existence proves the existence of an empirical reality outside me.' Thought, concepts, language cannot work without 'objective things' to latch onto.

The trouble is that this is just grist to the solipsist's mill. (I call this version of solipsism, 'transcendental solipsism'.) The point of the private language argument is not that there must be a language in *this* sense, but rather that the rules of language cannot come from me, otherwise 'whatever seems to me to be "right" will be right, which means we cannot talk about "right".'

If the rules cannot come from me, they must come from outside me, and not merely be *experienced* as 'coming from outside me'. Hence, Wittgenstein says, 'following a rule is a practice'.

This is a terribly difficult idea to get a handle on. The way I have tried to explain it is in terms of the example of the man with paranoid delusions. We understand the difference between 'how things are' as a question about my world, to be answered by my best judgement, and that same question raised with the added suspicion that my judgement might, for all I could ever know, be systematically and incurably distorted. With that idea necessarily comes the idea of an external reality that cannot be reduced to the 'best explanation I can give of my experience.'

So I would disagree with you about the question whether solipsism can be refuted. The solipsist cannot say, 'I know I have thoughts' because if there were no objective side they would not be 'thoughts' but only the semblance of thoughts. (If the solipsist accepts this and agrees to give up all talk of thoughts, knowledge or truth *then* they cannot be refuted.)

On the other hand (as I argued in my previous Shap paper at sophist.co.uk/glasshouse/documents/shap.html ) there is something I have which I cannot, in principle share with anyone else, something concerning which it is not possible even for me to make judgements, namely the way my brain state appears to me.

This bears on the intriguing possibility which you consider, of two solipsists whose worlds 'collide'. This cannot happen. Suppose you and I are wired up so that we literally share part of our brains in common. An experience which reaches a common part of our fused brains, arrives in our conscious minds at precisely the same moment. Each of us knows, without a shadow of a doubt, that the experience is, say, that of 'descending very fast in a lift'. But so long as our minds are distinct, neither has access to the other person's subjectivity, in a way that would prove, without further need for argument, that solipsism is false.

From this starting point, which I take to be the residual truth in solipsism, we can raise the question of what follows if we accept (as I have argued) that the idea of truth is conditional on the recognition of the reality of the other. I think what follows is the necessity for bring moral. But that is another story.

All the best,

Geoffrey