Epistemology -- the science devoted to the discovery of the proper methods of acquiring and validating knowledge.
Taking Philosophy Seriously...
Proceeding from Axioms in Objectivism - YouTube Edition
The Proof of Free Will (Libertarian Volition)
Introduction to Objectivist Epistemology, Exp. 2nd Ed. by Ayn Rand
The Evidence of the Senses: A Realist Theory of Perception by David Kelley