[lit-ideas] Dummettiana
- From: Jlsperanza@xxxxxxx
- To: lit-ideas@xxxxxxxxxxxxx
- Date: Fri, 13 Jan 2012 19:59:44 -0500 (EST)
Dummett's Truth
From:
http://eprints.lse.ac.uk/552/
(The whole interview contains commentary on voting, Tarot, etc.).
Cheers,
Speranza
---
quoted text:
Q: Could you describe your work in philosophy?
DUMMETT: Well, I’ll do my best. I have a kind of side interest in the
philosophy of time. One of the first things I published was an article arguing
that backwards causation (where the cause comes after the effect) was not
logically impossible. I suppose that the principal interest I’ve had, and
certainly what I’m best known
for, is a critique of realism and the truth-conditional theory of meaning
that underlies it. That is, the theory that the MEANING of a statement
consists in the condition for it to be true. Now, what we learn when we learn a
language is what counts as establishing a statement as true. Not, in
general, by observation but, more usually, by inference from premisses
established by observation. We also learn what you’re committed to by
accepting a
statement as true. That is the practice of speaking a language. But the
Realist position normally involves the Principle of Bivalence: that every
unambiguous statement is determinately either true or false. On that position,
the
being true of the statement can go beyond what we are capable of
recognizing. But what we are capable of recognizing consists in our ability to
recognize whether the statement is established as true. The simplest possible
example is this. It is normally assumed -- a realist assumption -- that the
magnitude of any physical quantity is absolutely determinate and exact, that’
s to say that it would be given in terms of some suitable unit, by a real
number which might be rational or irrational. We can never discover that.
We can only measure to within a margin of error. So, there is a statement
which is true but which we are incapable ever of recognizing as true. There
are plenty of such statements, and I want to question, I have questioned,
how we can come by such a notion as that of a statement as being true,
independently of our being able to recognize it as true? And how can we
manifest
possession of such a concept, and in any case, in what does it consist? It
seems to me that there is a circularity. You explain what it is to grasp
the proposition expressed by a statement, in terms of your grasp of another
proposition; namely that it would be true under such and such conditions.
That can’t be manifested in the actual practice of using the language,
because all that manifests is your capacity to recognize it, to recognize the
statement as true in favourable cases. So, if you reject this realist account,
this truth-conditional theory of meaning, you have to have a DIFFERENT
theory of meaning which I call justificationist (to understand a statement is
to know what would justify you in asserting it, in other words being able
to recognize it as true). And if you take that as your account of meaning,
you have to jettison this principle
of bivalence because there are statements for which we have no means of
recognizing
whether they’re true or false, so you can’t assume that every statement
is either true or false. I mean, you’re now identifying truth with the
existence of something whereby we could recognize a statement as true. That
means that you have to reject classical logic in favour of what’s usually
called intuitionist logic. So, now, I’ve never actually identified myself with
a
denial, a rejection of realism, I’ve been concerned simply to pose a
challenge to the Realist standpoint and ask how it can answer these questions
that I’ve posed about how do we get the concept of being true, and also to
work out the implications of denying realism and adopting the
justificationist theory of meaning. What effect does that have on metaphysics
essentially?
Is it coherent? I mean: are there problems which show it to be untenable?
So: that has been my major interest. I’ve written a great deal also about
the philosophy of Frege, I’ve retained my admiration for and interest in his
work, so that is exegesis. It is exegesis which brings you to the
frontiers of the subject, I think."
Q: Would it be fair to say then that the intuitionism in a sense underpins
the anti-realism?"
Dummett: Yes.
Q: So, would your take be something along the lines of Quine, who never
denied
that there are other possible logics—in fact nothing was ever sacrosanct
in his view—but just basically that you were stuck with bivalence because it
got you the results that you required in science, and it was simplicity
that was at stake? And are you saying in a sense that we shouldn’t just draw
boundaries, and we shouldn’t be so quick and content to retain boundaries.
That maybe we should just look a little bit further forward to see what we
might come up with if we put the full support towards something other than
bivalence? Is that a fair position of where you stand?
Dummett:
Yes.
Q: Of course you recognize bivalence and its power in what it does in
mathematics, but what would happen if?
Dummett:
Exactly.
Q: Another possibility to deny bivalence would be to accept multivalence.
Dummett:
Yes. But that is not the way that I’ve gone actually. In Intuitionist
Logic you can’t assert of any statement that it is neither true nor false,
that
would be for the intuitionist a contradiction. What you cannot do is to
assume that it is determinately one or the other.
Q: It is "P or not P" what is rejected."
Dummett:
Right. And you can’t ever close off the possibility that something will be
shown to be true. It may be very unlikely that it is, but there could
always be evidence that would turn up. So you can’t close it off."
--- end quoted text.
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