Consciousness, after all, (1) cannot be denied without self-contradiction (that’s Descartes’ point in“I think therefore I am”), but (2) it has none of the properties that characterize that is material (shape, size, mass, etc.), and (3) it has properties that are not material (e.g., “truth”). The existence of consciousness seems to immediately refute materialism.
--Peter Kreeft, Letters to an Atheist, 2014
