Monday, April 11, 2011

Realism, anti-realism and the reality principle

To: Ochieng O.
From: Geoffrey Klempner
Subject: Realism, anti-realism and the reality principle
Date: 1 December 2001 14:17

Dear Ochieng,

Thank you for your e-mail of 19 November, with your essay for the Metaphysics program, 'Realism, Anti-Realism and the Reality Principle'.

This is a fine essay which with your permission I would like to publish in Pathways News. You have explained the point that 'truth transcends verification' forcefully and with great clarity. I think that the readers will find this piece highly thought provoking.

My job is to criticise, and so I do have a criticism to make about your argument. I believe that you have missed something, a 'finesse' which the anti-realist is able to make at this point which undermines, or threatens to undermine the realist's position; although the arguments you give are valid and state things which it is important to state, in the face of relativist or crude anti-realist theories of truth which would deny that the truth is the truth irrespective of what we may believe.

To some extent, I will be repeating the argument made by the sophisticated anti-realist in the program. As an exercise for myself, I am deliberately not looking at what I wrote in the program as I write this.

So, let's see what the anti-realist can say.

The proposition that truth transcends verification follows logically from the definition of 'is true' as the 'predicate of disquotation'. In other words, the predicate 'is true' is the only predicate for which the following general statement is true:

For all propositions P, 'P' is true if and only if P.

If you substitute any other predicate that might be applied to a proposition for 'is true' then the general statement will no longer be true. For example, it is obvious that the following is false:

For all propositions P, 'P' is poetic if and only if P.

It may be the case that much poetry expresses truth, but we can think of plenty of examples of propositions which are poetic, but false.

It may be slightly less obvious that the following is false:

For all propositions P, 'P' has been verified by exhaustive tests if and only if P.

As your essay shows, the fact that a proposition has been verified by exhaustive tests does not entail that it is true. The tests can still produce the wrong outcome, as judged by further evidence, unavailable to the tester.

Now, the anti-realist accepts this logical principle about truth. However, the anti-realist does not accept the interpretation which the realist places on this principle. Take a proposition Q for which we have no certain of verifying its truth (in effect, that is just about any empirical proposition you can think of). By the logical principle, Q can be 'true or false' irrespective of our beliefs about Q. That is what the anti-realist accepts.

What the anti-realist does not accept is the way the realist understands that statement. (This is the hard part.) The realist thinks in this way: what is 'out there' in reality is a fact, it is given, actual even though we can never have certain knowledge of what is out there. The anti-realist proposes an alternative picture: There is nothing 'out there' in the realist's sense. What we call the 'actual' world is just a range of possible worlds: worlds in which the proposition in question is true, and worlds in which the proposition in question is false.

In a similar way, the fatalist says that there are facts about the future which are actual, even though we can never be certain what those facts are, while the anti-fatalist says that there are no facts about the future but only a range of alternate futures, which only become 'actual' when what was future comes to pass. The anti-fatalist is only selectively anti-realist. I.e. anti-realist about the future but realist about the present. The kind of anti-realist I am concerned with takes a 'global' anti-realist view, generalizing on the point made by the anti-fatalist.

All the best,

Geoffrey