The data on which philosophical theorizing is based are rather the intuited contents themselves, concerning the various thought experiments. At least that is so outside the epistemology of the a priori.

It is bad to want something that not even God could attain, especially when the impossibility becomes obvious.

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.

Epistemology now flourishes with various complementary approaches. This includes formal epistemology, experimental philosophy, cognitive science and psychology, including relevant brain science, and other philosophical subfields, such as metaphysics, action theory, language, and mind. It is not as though all questions of armchair, traditional epistemology are already settled conclusively, with unanimity or even consensus. We still need to reason our way together to a better view of those issues.

There is no need for the scientist to go into whether an observation was made, nor into the who, what, when, or where. The data on which scientific theorizing is based are rather the propositional contents of the instrument readings recorded, or the facts detected thereby.

When 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.

If the agent aims to make the attempt if and only if it would be apt, then a distinctive element of risk assessment becomes relevant: How probably would the agent succeed in attempting that fuller end?