Monday, September 04, 2006

Truth and the Future

We had the first meeting of my upper level epistemology course today. Among other issues we're taking up theories of truth. So one of the questions I posed was whether a statement about the future can be true at the time it is uttered.

A number of people said no, and I think the reasoning is something like this: a statement can't be true in the absence of the fact that makes it true, and since statements about the future are about events that have not yet happened, it is impossible for these statements to be true until those events come to pass.

That makes a certain amount of sense, but I still disagree: if statements about the future cannot be true, then that means it is impossible to have knowledge about the future (since knowledge requires truth) and that's too much of a sacrifice to make. Any theory that denies we have knowledge of the future, it seems to me, is a reductio ad absurdum.

In addition, and this should come as no great surprise, this line of thinking points in the direction of a pragmatic theory of truth (or so I think). After all, the line of thought described above links truth to specific facts that make a statement true. A pragmatic theory, on the other hand, might say that a statement is true if it would stand up to scrutiny for as long as you please. On the pragmatic theory it's no mystery how statements about the future can be true: to say they are true is just to say that they would stand up to scrutiny. Problem solved.


Blogger Brit Brogaard said...

Arthur Prior thought that the universe is genuinely indeterminate. As such, not all of our statements about the future can be true. For instance, my current utterance of "John will be going to a department meeting tomorrow" cannot be true or false. Prior thought that for a statement about the future to be determinately true (or determinately false), it would have to be true (or false) with respect to the future of all histories (i.e., continuations of the current state of the world). So, my current utterance of "John will be going to a department meeting tomorrow or it is not the case that John will be going to a department meeting tomorrow" is true. For it is true with respect to the futures of all continuations of the current state of the world (that is, it is true regardless of what happens tomorrow).

Personally I am very sympathetic to this view. But John MacFarlane (Berkeley) thinks "standard" semantics cannot make sense of it (even if it adopts Prior's method for determining future truth). MacFarlane thinks we need relativistic semantics.

8:52 PM  
Blogger Inside the Philosophy Factory said...

Why isn't it the case that you have knowledge of the present and past, but only beliefs about the future?

Perhaps the problem is that belief turns into a strange kind of future knowledge, but -- without a way to verify truth, saying you have knowledge in the future is a bit odd.

4:16 PM  
Blogger Joe Salerno said...

Hi John,

Here is my favorite problem for such theories of truth. Notice that there are truths that are never in fact scrutinized, like the one about the number of hairs currently on my head. Call this statement p. since it is true but is never in fact scrutinized, there is a truth of the following form:

(1) p, but p is never scrutinized

Since (1) is true, the pragmatic theory of truth says that it would withstand ongoing scrutiny. But it is logically impossible for (1) to withstand scrutiny. For any attempt to scrutinize the left conjunct will falsify the right conjunct.

10:58 PM  
Blogger Sharon Crasnow said...

(1) is a statement about language whereas I took John to be discussing the relationship between language and the world. Is it possible that these two types of statements work differently? There are surely other cases where they do.

John, I am not so sure what we are losing when we give up the truth of future statements. What work is their truth doing?

4:02 AM  
Blogger John Capps said...

Sorry for taking so long to respond to these comments - I don't know where the time has gone!

Berit, thanks for the references to Prior and MacFarlane.

ITPF, I guess I don't see what's so strange about having knowledge of the future, especially if we're talking about the very near future, like 2 seconds from now. Certainly I can have justified beliefs about the future (especially the near future), and what can that mean except that the belief is more likely true than not?

Joe, I don't want this to appear naive, but I have difficulty understanding what a never-scrutinized truth is. I can understand that how a leaf in a forest might never be scrutinized, but it just strikes me as metaphysically inflationary to say that there are truths that might never be scrutinized.

Of course, that's what a pragmatist would say, I think, and it's because truth, for a pragmatist, is so closely bound up with things that matter. Because an "unscrutinized truth" (like the # of hairs on your head) seems to be a "truth" that doesn't matter, I'm hesitant to even call it a truth. Or if it is, it's a degenerate case, and not really a threat to the core idea behind the pragmatic theory of truth.

Sharon, I agree with what you write about language and the world; as far as the importance of truths about the future, I think it's this: if they can't be true, then I can't see how to make sense of having justified beliefs about the future. So I desperately want to have justified beliefs about the future, otherwise I've conceded too much to the skeptic.

11:13 PM  

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