Thanks again for your answers. Just 1 more and then I guess we'll leave it mostly unresolved, as these things usually are.

I'm not sure you're using 'prima facie' the way philosophers use it.

Perhaps not.

According to phenomenal conservatism, when you consider modus ponens and it seems valid, you thereby acquire prima facie justification for believing that it's valid.

Doesn't the fact that you first consider it and only after decide it seems valid mean your belief is not prima facie (at first sight) at all? It seems a contradiction to speak of "acquiring" prima facie justification for believing something after consideration. I think philosophers may mean "at early sight with little conscious thought", not "at first sight". I wouldn't call this intuition ( knowledge acquired without inference or the use of reason ), but Huemer seems to use the word in a number of different ways so there is always one available to make his sentences true.

How do you identify which beliefs are justified and which are unjustified, if not by intuition?

Let me use an analogy. Suppose you claim you built a house out of atoms. I suppose that's true in a sense. It just seems odd to say it that way. You are not manipulating or perceiving individual atoms. You are using already complex materials like wood and nails etc. Likewise it seems odd to me to say you are justifying your beliefs through intuition. Intuition, in the the sense I defined it above, is invisible to us. We can't use it directly to justify anything. Rather we use ideas justified by other ideas justified by other ideas, etc, The chain of justifications disappears gradually into our unconscious and out of our view. It isn't the case we can pick one out and call it prima facie. Any idea which appears to our consciousness is not intuition in the the sense I defined it above.

But then, maybe our disagreement is mostly about the meaning of "intuition"?