Can propositions about the future be true?
From a discussion on Yehoodi, Dan2513 writes:

While I agree with you that foreknowledge itself does not change too much whether you are using an A or B theory of time, I hasten to point out that if you do not believe future events have truth values (I disagree with this), you can consistently hold that God is omniscient yet does not know the precise outcome of the event. The reason being that omniscience only requires that God knows all things that are true. If future events do not have truth values, then God knows them at exactly the moment at which they become true. Of course, this belief is not compatible with the B theory of time because that entails that God is present at all moments in time and never has to "wait around" for an event to instantiate along with its truth value.

There's much that's muddled here, but also the kernel of an idea that I find interesting. First the muddled parts:

According to the "Justified True Belief" definition of knowledge that goes back to Plato's Theatetus:

S knows that p iff:

• (i) p is true;
• (ii) S believes that p;
• (iii) S is justified in believing that p.

Since this model already stipulates that p is true, stating that "God can only have knowledge of things that are true" is simply redundant.

Secondly, the suggestion that events have truth values is problematic. What does it mean to say that an event has a truth value? Say you and I witness something striking, like a car wreck, and I point to it and say "that was true" or "that is false!" Pointing to an event (or a situation) and saying it's true or false seems incoherent. I think it's more correct to state that only propositions can have a "truth value," as suggested by clause (i) of the JTB model. Thus I might say "the guy in the red corvette was going way too fast" and that'd be something we could argue over.

Now the not so muddled question: can propositions about the future be true or false?

"It's going to rain tomorrow!" I can certainly believe that. And my belief can be justified (at least partially)-- the weatherman says its going to rain and he's almost always right. But can that proposition be true at the very moment I utter it? How would we verify its truth? We can't exactly look into the future. Or can we?

On the one hand, it seems that all statements about the future are merely conjectures which could turn out false. Who knows? Tomorrow might never happen. The universe might explode at 11:59pm. At best, it seems we can say their truth value remains undecided until the future arrives. But if that's true, then we can't have knowledge of the future, not the JTB sort of knowledge, at any rate.

If I'm here tomorrow, I'll follow up with some more thoughts on a priori vrs a posteriori propositions.
- posted by mike @ 9:38 PM