Intuitions, Reasons, and Compatibilism

In class yesterday, we discussed the role of intuitions in philosophy. It came up because John Martin Fischer has a chapter in the book we're reading in which he seems to rely on a kind of epistemic principle involving intuitions. We had trouble articulating the principle in class. Perhaps the entry on intuitions in the SEP will be helpful in clearing up some of the questions that arose in my class and will help us spell out the principle that Fischer seems to have in mind.

Here's a principle like one we considered in class (and which is not that far from one mentioned in the SEP entry). I'll call it principle "P"

P = If a theory (generalization, etc.) contravenes the content of an intuition, then that intuition should be treated as (defeasible) evidence against the theory.  

Fischer doesn't explicitly endorse this principle, but he does seem to think that, all else being equal, our theories (beliefs, views, etc.) should be in keeping with our intuitions. That is, he seems to think that if a theory is not in keeping with an intuition, then this is a reason (albeit a defeasible one) for thinking that the theory is false.

The majority of students in my class didn't take issue with this sort of principle, but a number of them were skeptical of the reliability of intuitions in providing reasons to endorse a theory (have a belief, etc.). I was surprised, in fact, by the level of skepticism about principles like P.

A related issue that we discussed involved how we ought to unpack Fischer's argument at the beginning of the chapter (and whether he was intending to really offer an argument).

We might read Fischer as having put forward the following argument:

(1) We have the intuition that we're sometimes free and morally responsible for what we do, and we would have this intuition even if determinism turned out to be true.
(2) We thus have the intuition that compatibilism is true.
(3) Incompatiblism contravenes the content of this intuition (i.e., the intuition that compatibilism is true).
(4) Principle P.
(5) Therefore, the intuition that compatibilism is true provides (defeasible) evidence against incompatibilism.  

Is this an accurate way to unpack Fischer's argument? Even if it's not, what do you make of the argument and what do you think about Principle P?