THE THOUGHT AND REALITY OF MICHAEL DUMMETT

By Thomas Riggins

The British thinker Michael Dummett is generally considered one of the most important living philosophers writing in English. The TLS of 2-8-08 has a review of his new book (based on the Gifford Lectures he gave in 1996-97) “Thought and Reality”: Paul Boghossian “Powers for the divine.”

Having recently re-read Lenin’s “Materialism and Empirio-Criticism”, I was struck by the similarity of the problems being dealt with today by some contemporary philosophers and those dealt with by Lenin a century ago. I will use Leninist terminology in braces {}to make the arguments clearer.

Boghossian says that Dummett has been occupied over his career by two “master thoughts.” Master thought one is “that the metaphysical dispute between a realist {materialist} and anti-realist {subjective idealist}” about a particular area of reality (or “domain”) can only be seen as a disagreement about “the meaning of statements” about the area in dispute. Master thought two is that the theory of meaning provides a general argument “which tends to favour anti-realist {subjective idealist} conceptions of meaning over their realist {materialist} alternatives.” Let us see if much has changed since Lenin’s day.

Boghossian illustrates Dummett’s views by taking a mathematical example. In 1742 Christian Goldbach proposed “every even integer greater than two is the sum of two primes.” A mathematical realist who thinks the number system has an objective existence thinks that Goldbach’s proposition is either true or false independently of us. An anti-realist holds that the number system is the a construct of the human mind and the answer to Goldbach’s proposition is only true or false if “we have built enough into our notion of number to settle the matter.”

Enter Dummett’s First Master Thought: this dispute can only be resolved on the basis of whether or not math statements are true or false even if we cannot show that they are or not. That is, do they have what he calls JUSTIFICATION-INDEPENDENT TRUTH CONDITIONS. The question now becomes, according to Boghossian, can something be true “even if we have no justification for accepting it” or do we need a proof or some such justification in order for something to be true?

Enter Dummett’s Second Master Thought: the theory of meaning, according to Dummett, implies that without JUSTIFICATION CONDITIONS our statements about things have no meaning. If follows that there are NO justification-independent truth conditions. Thus the mathematical anti-realist is correct. This applies to all domains or areas of knowledge (so my use of “materialism” and “subjective idealism” is not too far off the mark as it may have been if ONLY the philosophy of mathematics was involved).

Boghossian thinks Master Thought One maybe have something in its favour but that Master Thought Two, justificationism, has too many problems. When it comes to a statement about the past, for instance, the truth or falsity of “X occurred” seems to common sense to depend on if “X occurred” or not and not on if we can give a proof or justification about the occurrence one way or another. Dummett seems to realize this problem and in another book, "Truth and the Past” tries to deal with it.

With respect to the past, Boghossian writes, Dummett says, in effect, that statements about the past are true “if and only if anyone suitably placed in time and space would be, or would have been, in a position to establish it as true.” But what about situations where it would have been totally impossible for someone to have been “suitably” placed—such as the moment of the Big Bang?

Dummett is led by his anti-realism, as Boghossian points out, “to the view that there could not have been a world without sentient beings.” But we know that the earth existed before there were any sentient beings on it. Also human beings have a different kind of sentience than other beings, so how do we explain living in a “common world?” “The realist {materialist},” the reviewer writes, “who believes in the world as it is in itself, independent of our ways of apprehending it, would easily be able to make sense” of all these problems. But how can Dummett do so?

Just as his great predecessor Bishop George Berkeley did, Dummett calls in God to be the guarantor of his system of justificationism. And here is the link between Lenin and Dummett. Anti-realist {idealist, and especially subjective idealist} arguments are as old as the hills, and a good reading of “Materialism and Empirio-Criticism” may make you doubt that Dummett is “one of philosophy’s most searching minds” (his other big interests are tarot and Roman Catholicism, to which he has converted)—but we can at least agree that his book “may not be the last word on the difficult issues it treats.” That book came out in 1908.