Tuesday, March 15, 2011

"I am obliged to A at t"

Under the influence of my previous post, no doubt, I found myself wondering about ought and tense. Specifically, whether "I am obliged to A at t" (e.g., "I am obliged to teach at 9:30 am today") is a statement about two times—the present and t—or just a statement about t. On the one-time reading, "I am obliged to A at t" has the logical grammar of "At t, I will be obliged to A." On the two-time reading, the logical grammar is "Now, I am obliged to A at t.

The conclusion was that the two-time reading is correct. Here's an easy argument. The following is intelligible. You are not currently obliged to A tomorrow. But five minutes later you validly promise me to A tomorrow, and after you've made the promise, you are obliged to A tomorrow. Five minutes later, I release you from your promise. You are no longer obliged to A tomorrow. So you can change in respect of what you are obliged to do tomorrow. On the two-time reading, this makes perfect sense. At t0, it is not yet the case that you're obliged to A at t3; at t1 you are obliged to A at t3; then at t2 you cease to have this obligation to A at t3. But if the statement were solely about what happens at t3, then there could not be any change in respect of it, since what happens at t3 does not change in this back-and-forth way.[note 1] Moreover, that I am currently obliged to A tomorrow places constraints on what I may permissibly do today.


patrick said...

Hey Alex,

Re: your Note 1 -- yes, but see my paper in the newest OSPR (Vol III), "Geachianism." :)


Alexander R Pruss said...

Neat paper, Patrick, which I've just skimmed, so I may have missed something relevant to what I will say.

Here's a worry. The following sounds fine: "At t0, it was going to happen that at t2 I would break a leg, but you prevented it by your timely action at t1."

But the following sounds bad: "At t0, it was true that at t2 I would break a leg, but you prevented it by your timely action at t1."

In other words, "it is going to happen that" and "it will be the case that" are not exactly interchangeable in these cases. The former, I think, expresses a disposition.

I also think that "it was going to happen that" has a contextual dependence which "it was the case that it would be that" lacks. Take the case of a chancy preventer, whose probability of preventing is p. If p is very big, we don't want to say "it was going to happen that". If p is very small, we do want to say "it was going to happen that". Where the boundary between us being willing to say it and us being unwilling to say it is going to be drawn will depend on the context. But I don't think we make a similar distinction on the "will" side.