I accept the following two claims:
- Every free action is done for a reason.
- If an action is obligatory, then I have on balance reason to do it.
It strikes me that this version of the problem of akrasia may not be particularly difficult. There is no deep puzzle about how someone might choose a game of chess over a jog for a reason. A jog is healthier but a game of chess is more intellectually challenging, and one might choose the game of chess because it is more intellectually challenging. In other words, there is a respect in which the game of chess is better than the jog, and when one freely chooses the game of chess, one does so on the basis of some such respect. The jog, of course, also has something going for it: it is healthier, and one can freely choose it because it is better in respect of health.
Now, suppose that the choice is between playing a game of chess and keeping one's promise to visit a sick friend. Suppose the game of chess is more pleasant and intellectually challenging than visiting the sick friend. One can freely choose the game of chess because there are respects in which it is better than visiting the friend. There are, of course, respects in which the game of chess is worse: it is a breaking of a promise and a neglecting of a sick friend. But that there are respects in which visiting the sick friend is better does not make there be no reason to play chess instead, since there are respects in which the chess game is better.
But isn't visiting the sick friend on balance better? Certainly! But being on balance better is just another respect in which visiting the sick friend is better. It is still in some other respects better to play the game of chess. If one freely chooses to play the game of chess, then one chooses to do so on account of those other respects. That one option is on balance better is compatible with the other option being in some respects better. It is no more mysterious how one can act despite the knowledge that another option is on balance better than how one can act despite the knowledge that another option is more pleasant. The difference is that when one chooses against an action that one takes to be on balance better, one may incur a culpability that one does not incur when one chooses against an action that is merely more pleasant, but the incurring of that culpability is just another reason not to do the action.
But isn't it decisive if an action is on balance better? Isn't it irrational to go against such a decisive reading? Well, one can understand a decisive reason in three ways: (a) a reason that in fact decides one; (b) a reason that cannot but decide one; and (c) a reason that rationality requires one to go with. That an action is on balance better need not be what decides you, even if in fact you do the on balance better action. Now, granted, rationality requires one to go with an on balance better action. But that rationality requires something does not imply you will do it.
But if you don't, aren't you irrational, and hence not responsible? Well, if by irrational one means lack of responsiveness to reasons, then that would indeed imply lack of responsibility, but that is not one's state when one chooses to do the wrong thing for a reason. It need not even be true that one is not responsive to what is on balance better. For to be responsive to a reason does not require that one act on that reason. The person who chooses the chess game over the jog is likely quite responsive to reasons of health. If she were not responsive to reasons of health, it might not be a choice but a shoo-in. Likewise, the person who chooses against what is on balance better is responsive to what is on balance better, but goes against it.
Now, of course, the person who knowingly does what she knows she on balance has reason not to do, does not respond to the reason in the way that she should. In that sense, she is irrational. But that sense of irrationality is quite compatible with responsibility.