Consider a version of John Perry's argument that action needs tense. You promised to call a friend precisely between 12:10 and 12:15 and no later. When it is between 12:10 and 12:15, and you know what time it is, this knowledge, together with the promise, gives you reason to call your friend. But if this knowledge is tenseless, then you could have it at 12:30, say. Thus, absurdly, at 12:30 you could have knowledge that gives you just as good a reason to call your friend.[note 1]
Here, however, is a tenseless proposal. Suppose it is 12:12, and I am deliberating whether to call my friend. I think the following thought-token, with all the verbs in a timeless tense:
- A phone call flowing from this deliberative process would occur between 12:10 and 12:15, and hence fulfill the promise, so I have reason that this deliberative process should conclude in a phone call to the friend.
For suppose that at 12:30, I am again deliberating whether to call my friend. I have, on this tenseless proposal, the very same beliefs that at 12:12 were expressed by (1). It would seem that where I have the same beliefs and the same knowledge, I have the same reasons. If this principle is not true, the Perry argument fails, since then one can simply affirm that one has the same beliefs and knowledge at 12:30 as one did at 12:12, but at 12:30 these beliefs and knowledge are not a reason for acting, while they are a reason for acting at 12:12. But I can affirm the principle, and I am still not harmed by the argument. For what is it that I conclude at 12:30 that I have (tenseless) reason to do? There is reason that the deliberative process should conclude in a call to the friend. But the relevant referent of "the deliberative process" is not the deliberative process that occurs at 12:30, call it D12:30, but the deliberative process that occurs at 12:12, call it D12:12. For (1) is not about the 12:30 deliberative process, but about the 12:12 one.
The principle that the same beliefs and knowledge gives rise to the very same reasons may be true—but the reason given rise to is a reason for the 12:12 deliberative process to conclude in a phone call. But that is not what I am deliberating about at 12:30. At 12:30, I am deliberating whether this new deliberative process, D12:30, should result in a phone call to the friend. That I can easily conclude that D12:12 should result in a phone call to the friend is simply irrelevant.
There is an awkwardness about the solution as I have formulated it. It makes deliberative processes inextricably self-referential. What I am deliberating about is whether this very deliberation should result in this or that action. But I think this is indeed a plausible way to understand a deliberation. When a nation votes for president, the nation votes not just for who should be president, but for who should result as president from this very election. (These two are actually subtly different questions. There could be cases where it is better that X be president, but it is better that Y result as president from this very election. Maybe X promised not to run in this election.)
[I made some minor revisions to this post, the most important of which was to emphasize that (1) is a token.]