I think it's ok to have wishes that conflict with each other - it's irrational to try to make them both come true, but not irrational simply to have them.

Suppose whether or not someone tells me a lie depends only on whether he wants to, but he is morally indifferent, he doesn't care much about the truth or about me, and his self interest, which he worships, tells him to lie, and so it comes about that given his psychology, it is a forgone conclusion that he will lie to me. I think in this case he is still blameworthy, and that implies, among other things, that he did something he ought not do.

I don't think we are all irrational every time we fail to see through an argument in a book, but suppose it's true about you. You are still more rational than you think you are. You are irrational in a minor way - believing a misguided theory of the nature of rationality - but rational in a major way - you respond well to probabilistic evidence as you go through the day.

I am not committed in any way to the traditional concept of character - the concept of "character trait" as involving predictable behavior. I am committed to a view in the neighborhood - the view that the moral worth of one's actions depends on the quality of will expressed in them.

I don't think any of my desires or beliefs or other mental states are external to me. Many people will occasionally feel alienated from the motives for an action - "whatever possessed me to do that?". Note, however, that some people feel alienated from the white hairs that recently appeared on their heads - "who put them there?", they might ask the mirror - but the white hairs are still theirs. Similarly, I might feel alienated from an action or a mental state because it does not fit with my visceral self - image.

Though we think intrinsic desires tend to be pretty stable, we do not think they imply anything like the amount of predictability in behavior that traditional virtue ethics requires for someone to have a one-word-in-English character trait such as "benevolence". Other things being equal, a person with more of a desire for other people's wellbeing will do more for other people's wellbeing, but things are almost never equal.

Duties concern things that are voluntary. I do think that if you have a moral duty to bring me back the book you borrowed, that implies, roughly, that your doing so depends on your wanting to do so: if you want to bring me the book, you will. This is not the case if you are stuck at some airport due to a snowstorm, far away from me. This, however, is not the same as "ought" implying a metaphysical "can".