Conflicting wants

Here's Raz:
"We cannot literally believe that p and that not-p. But there is no contradiction in both wanting to perform an action or to have an object, and wanting not to do the action or not to have the object."
(Engaging Reason, p54)

Is this correct? It seems true that people cannot believe both P and not-P, no matter how irrational they are. One simply wouldn't count as believing, in the normal sense, in these circumstances.

But it seems to me that the same is true of wants. I cannot want to read this book for its insight and also not want to read it for its insight. Unless of course there is some parts of its insight I want, and some I do not. But then we do not have two literally opposed wants: we want the same object for some reasons but want to avoid it for others. That's not analogous to believing both P and not-P. It's analogous to believing that something is P in respect of one aspect, and not-P in respect of some other (e.g. that this car is red in some places and not-red in others).

So in both cases, literally believing, or wanting, P and not-P is not possible. And in both cases literally believing, or wanting, P in some respect and not-P in others is possible. So it seems to me.