We need some standard that will determine how likely a belief is to be true given just that it is stored in one of us, including strangers that one can ask for directions, and with whom one might collaborate.

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.

I am mainly concerned with unqualified knowledge, by contrast with the varieties of expert knowledge: scientific knowledge of various sorts, legal knowledge, medically expert knowledge, and so on.

There isn't a formal definition of success.

There's not much to be done about the impossibility. One must instead get rid of the desire.

When I accept someone's testimony, I am thus only a small part of the full seat of epistemic competence, which might include many others in a long chain. My own contribution might then be slight, just through the perceptual and linguistic competence involved in knowing what someone is saying or writing, etc.

When you dream, your perceptual (and other) competence is affected. You are then unable to get it right competently with the beliefs in your dream.