In 1995 David Chalmers distinguished the “easy” problems of explaining how the brain processes information from the hard problem: why any of this is accompanied by felt experience. The question has revived interest in views once marginal in philosophy, including panpsychism and the idealism of the contemplative traditions.
Hard Problem of Consciousness
David Chalmers’s name for the question why physical processes give rise to experience at all.
Also: the hard problem