To: Ricco L.
From: Geoffrey Klempner
Subject: The significance of scepticism
Date: 16 May 2001 13:56

Dear Ricco,

Nothing can go wrong today. I am sitting in the garden with your essay and my Psion palm top computer. The sun is struggling to come out. This is the first mild weather we have had.

Thank you for your e-mail of 8 May, with your essay for Possible World Machine on the Significance of Scepticism.

You have done well on laying out the sceptic's case. It is perhaps not quite so clear what conclusions you think we should draw. At the end of your essay you mention G.E. Moore and Norman Malcolm, two stout opponents of scepticism. I am not sure what you think about their arguments.

You indicate (very briefly) two lines of resistance to the sceptic's argument:

1. We have to be more circumspect in our knowledge claims - and learn to make do with 'fallible knowledge'. In other words, all the sceptic has shown is that there is no such thing as Knowledge with a capital 'K'. But we can still have the ordinary sort of fallible knowledge, with a small 'k'.

2. I KNOW that I have two hands, I KNOW that this is a tree, therefore the sceptic must be wrong in claiming that I do not have knowledge.

Now, which argument is your point about the lottery ticket a reply to?

Is the sceptic is saying, ‘You say you are happy with fallible knowledge. But that’s like thinking you hold a winning lottery ticket, when in fact you haven’t won.’ We have the satisfaction of thinking we have something we call ‘knowledge’,but if it isn’t REAL knowledge, then we have no right to feel satisfied. Is that it?

Regarding the arguments for scepticism, it is important to distinguish two distinct strands. The first, illustrated by your tale of the happy fish, concerns the problem of justifying an inference from one level to another. E.g. the inference from the frisky motions of the fish to their inner state of mind. Or similarly from a person's observation of the expression on your face and your shouts of joy.

The second strand concerns specifically the problem of induction: why information about things that have happened in the past should have any relevance to what will happen in the future.

However, the fish example shows more than this. 'You don't know my state of mind, therefore you don't know that I don't know' involves an assumption about knowledge, or about what it takes for something to be knowledge, that a philosopher would certainly wish to question. The assumption is that knowledge is characterized by a subjective state which is such as to guarantee the truth of what is believed: in other words, Descartes' notion of 'clear and distinct ideas'.

Even if God could give Wei Zi the power to see into Zhong Zi's mind, he would still be none the wiser concerning Zhong Zi's state of knowledge concerning the mind of the fish.

Yet another issue raised by this story (the fact that the story raises not one but several philosophical questions explains its peculiar power) is the problem of making SENSE of the assertion that the fish is happy. I know what it is for you or me to be happy: we are two of a kind, the kind 'human being'. Now, what exactly are we being asked to do; 'Take that, take your subjective state, and imagine IT being in the fish'? It? What?

One can see this as a second line of attack on the Cartesian epistemology that underlies the fish story. To attack Cartesian epistemology looks to me the most promising line of resistance against the claims of the sceptic, in this case. Unfortunately, attacking Cartesian epistemology does not help us defend against the sceptic’s doubts concerning induction.

As you say, ‘The sceptic highlights that we live by our own sheer invention’. That is a frightening and disturbing prospect. Should we not be so frightened? Is that the way to answer the sceptic? Or should we reject the sceptic’s claim that our world is merely ‘invented’?

All the best,

Geoffrey