Khan Academy: Epistemology: Paradoxes of Perception #2 (Arg From Hallucination)

Common sense takes for granted that we can typically just see physical objects without further hindrance. In this Wireless Philosophy video, Eugen Fischer (University of East Anglia) presents the 'argument from hallucination' that questions common sense: Together with parallel arguments, it appears to show that we are cut off from any physical objects around us by a veil of immaterial perceptions.