I usually don't take too well to intuitionist models of ethical knowledge. They strike me as simple-minded, devoid of explanatory strength, pretentious, whatever. Moore and Ross, for instance, failing (somehow!) to realize that moral questions have practical answers, blithely assert that our duties readily escape our awareness of them, not for lack of trying on our part but due to unavailable levels of relevant information or I don't remember what Ross said to the same effect, but I know he said something to it.
So it comes as a welcome surprise that, despite its demerits, I've discovered in Prichard a nicer idea. Instead of attributing, to us, inexplicable receivers for a conceptually irreducible property of moral value or rightness in the reality outside of ourselves, he seems instead to describe our obligations as known introspectively. I'll admit that saying obligations just float inside our minds isn't altogether better than what Moore and Ross say, but it IS better to some extent, finding some support in an interesting point Prichard makes about how right actions are right. I'll let you read Dancy's article in the SEP (
plato.stanford.edu/entries/prichard/), sec. 3., for what I mean by this.