I have just started studying Gibbard's Thinking How to Live, and have a question about it.
Consider the following, apparently valid, argument:
(1) Either it is before 5 or I should leave now
(2) It is not before 5
Therefore, (3) I should leave now.
Presumably if Stan believes (or accepts) 1 and 2 for good reasons,
then he has some reason to believe (accept) 3. Some would go further and say, for example, that Stan is
rationally required to believe 3, but let's stick with the less contentious
claim that, in these circumstances, he has some reason to believe (accept) 3:
(SR) Stan has some reason to believe 3
My question is whether Gibbard can account for SR's being true in
the situation I have described (or a suitably cleaned up cousin situation).
I have my doubts, based on the following Gibbardian translation of Stan's "beliefs" that 1 and 2 are "true" – my source here is Chapters 3 and 4 of Thinking How to Live:
(BG1) I rule out [rejecting that it is before 5 & rejecting that I should leave now]
(BG2) I reject that it is before 5
Presumably if Stan has good reason to adopt attitudes BG1 and BG2, then he also has good reason to adopt this attitude:
(BG3) I rule out [rejecting that I should leave now]
But that is not the same as
(BG3*) I accept that I should leave now
which is, I think, the Gibbard translation of
(B3) I believe I should leave now.
Moreover, it is hard to see how having reason to adopt BG1 and BG2 leads to your having some reason to adopt BG3*, because, on Gibbard's view I could "conform" to BG3 by either (i) being agnostic about whether I should leave now or (ii) adopting BG3*. So, by being agnostic, Stan could consistently adopt BG1, BG2, BG3, and not adopt BG3*. And it is not clear why he would have a reason to change his mind.
I do not have command of Gibbard's new system or the secondary
literature yet, and worry that my doubt is based on a confusion. I would love to clear any such
confusion up, before I keep studying the book.
Does Gibbard have a good response to my worry, perhaps one based on his concept of hyper-plans? Has anyone (maybe Gibbard) discussed this objection? Is it based on a mistake or misunderstanding?