There isn't a formal definition of success.

In my view (animal) knowledge is apt belief, where not only the belief (its existence and content) but also its correctness is creditable to the subject's competence.

It is also certain that when we assent to some piece of reasoning when our perception of it is lacking, then either we go wrong, or, if we do stumble on the truth, it is by accident, so that we cannot be sure that we are not in error.

In my view there is a level of human knowledge that involves just getting it right aptly. This "animal" epistemic level is an inferior level in just the way of Diana's long shot in the dark while drunk. That shot is inferior in a certain respect if too poorly selected as a hunter's archery shot, even if not quite as poorly selected as would be a shot aimed at the moon. Even if Diana's too risky shot turns out to be apt by attaining success through sublime archery dexterity, it is still inferior in the particular respect of being so risky and hence so poorly selected.

In order to qualify as a judgment, an affirmation must aim at getting it right aptly, through competence, and not just through a lucky guess.

The success of an archery shot may bring food to the hunter's starving family, or may constitute a horrible murder. But these outcomes are irrelevant to the assessment of that shot as a hunter-archery shot, as an attempt to hit prey without running excessive risk of failure.

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.