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.
Ernest SosaWhen we speak of ordinary unqualified knowledge, my thought is that we are implicitly relativizing to the standards imposed by our evolution-derived humanity. These are standards that determine when we consider it appropriate to store beliefs just as a human being, rather than in one's capacity as an expert of one or another sort. Such stored beliefs are to be available for later use in one's own thought or in testimony to others.
Ernest SosaGiven its more substantial aim, a judgment is apt only if its constitutive alethic affirmation is not only apt but aptly apt. The subject must attain aptly not only the truth of his affirmation but also its aptness. And that in turn requires not only the proper operation of one's perception, memory, inference, etc., but also that one deploy such competences through competent epistemic risk assessment.
Ernest Sosa