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Does a proposition about the future have to be true today? If so does this preclude contingency and is every proposition of the future necessary?
Accepted:
August 4, 2007

Comments

Allen Stairs
August 5, 2007 (changed August 5, 2007) Permalink

Let's start with an analogy and see how far it gets us. Suppose I consider a proposition about some distant place. Suppose I consider the proposition that the population of Woodstock, New Brunswick (my home town in Canada) is over 6,000. [To keep things simple, assume that I mean the population today, August 5 2007.] I'm contemplating this "here" in Washington DC. But it's a proposition about some other place -- "there," not "here." And now consider the question: "Does this proposition about Woodstock have to be true or false here in Washington?"

The question seems a little odd. What the proposition asserts refers to a particular place, but the idea that the truth of the proposition is, as it were, tied to the place where it's being contemplated seems off. We might put it this way: the proposition picked out by my use of the sentence "Woodstock has a population over 6,000" is true if the population of Woodstock really is over 6,000 and false otherwise. Asking if the proposition is true here is asking a bad question.

So one might argue that we should say much the same thing about a proposition such as "The President of the USA in 2033 will be a Democrat." I'm contemplating it at a particular time, different from the one that the proposition refers to, but that doesn't give us a reason to tie the truth of the proposition to the time when someone is considering it. On analogy with our previous example, we might say that the proposition I consider when I ask "Will the President of the USA in 2033 be a Democrat?" is true or false depending on whether the American president in 2033 is a Democrat, in the timeless sense of "is."

We might argue this way. But it inevitably feels odd to many people. That's because we don't think of space and time in the same way. Most of us have no doubts about the reality of distant locations. Distant times, and especially, future times provoke a different response. We tend to think of the future as "not yet real." We may think that while there is a fact of the matter about Woodstock's population ("Now," we might add), there is no such fact about the Presidency in 2033.

We've now landed in the middle of a larger metaphysical debate. We're inclined to take our talk of past, present and future (McTaggart's "A-series") as having ontological bite, and to think of the world as a place of "becoming." However, many philosophers argue that this point of view is untenable for very general reason, and that in particular it's hard to square with the view of space and time that Special Relativity seems to embody. In relativity, there's no privileged answer to the question "What is simultaneous with event x?" That makes it hard to single out some ontologically privileged "now" that carves propositions up into ones with truth values and ones that, so to speak, await the arrival of their truth-values.

There's a lively debate about all this; you might look for a copy of Craig Bourne's A Future for Presentism. But to get to the second part of your question, suppose we accept the view that propositions about the future have definite truth-values. Do we then end up having to say that all propositions about the future are necessary?

I would say no. Here again, an analogy might be useful. As it happens, right now there are 4 coins in my pocket: two quarters, a dime and a nickel. But that pretty clearly seems to be a contingent fact. It might very well have turned out otherwise. And whether there will be the same collection of coins in my pocket an hour from now depends on what I do in the meantime. If I leave things as they are, I'll still have just these coins in my pocket. If I buy that $.65 pack of gum from the vending machine, I won't. Even if it's true that in an hour from now, there will be no coins in my pocket, it may be true because of a contingent fact about what I do in the next few minutes.

We could add more detail here, and spelling all of this out really carefully would take quite a few words. But the short version is something like this: one possible view is that the universe just consists of a certain totality of events. Which propositions are true depends on which events, arranged in what way. But that the universe consists of one set of events as opposed to another might well be (plausibly is) a contingent matter and indeed, what later events there are may depend causally on contingent facts about the things we do here and now.

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Alexander George
August 6, 2007 (changed August 6, 2007) Permalink

In connection with Professor Stairs' last two paragraphs, you might also read Question 997 and some of the further entries referred to there.

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