How do we know what we know? What do we know?
To that most lucid of Scottish empiricists, David Hume (1711-1776), the answer to the first question was a straightforward, if deceptively simple, "by experience."
Everything we know about knowing, Hume would argue, is acquired through experience.
Hume was a deadly, if jovial, enemy of creationists. For this reason alone, we should read him today.