When I see two owls and then two more owls and conclude that I see four owls, I am responding to reasons, and it better not be my choice to believe that two plus two always equals four. If I am a rational person, I will have that belief by necessity, whether I wanted to or not. So it's not that strange to discuss responding to reasons out of necessity.

Suppose a student of mine writes in her exam that "morality is completely relative to culture, so nothing is absolutely right or wrong. Because of that, it is absolutely wrong to be culturally intolerant". This student, if she believes what she writes, believes a contradiction. She ought not to believe the contradiction - it's a basic epistemic norm. This is true even if she can't avoid believing it - no amount of studying will show her the light.

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.

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.

Virtue is about wanting right and good things, not about being particularly good at thinking.

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".