We must distinguish judging from guessing.

Flourishing is properly the main human end, and flourishing is activity of soul that succeeds in accord with virtue.

Arguably, if you view a real barn in bright sunlight and close by, while fully alert and otherwise in good shape, then you do know whether or not you see a barn. You have "animal" knowledge, says my virtue theory, through the first-order aptness of your judgment.

When there are conflicts of observation, when experiments cannot be replicated, scientists may then retreat to a study of the various specific observations so as to explain the conflict, in the course of which they would make use of the concept of observation, or of some specification of that concept.

Knowledge in my view is a form of action. It involves endeavors to get it right, and more broadly it concerns aimings, which can be functional rather than intentional.

Suppose we wonder whether we should trust the deliverances of our basic epistemic competences. If those are indeed our basic competences, then in order properly to satisfy our curiosity we will inevitably rely on one or more of them. So, either we squelch our curiosity or we will have to fall into the circularity or regress to which the skeptic objects.

Philosophers need not much use the word 'intuition' or the concept of intuition, except when they happen to be working on the epistemology of the a priori.