What is the so-called "hard" problem of consciousness? In this video, philosopher Massimo Pigliucci argues that it doesn't exist. Or at the least, it isn't different from the "easy" problems (which aren't really that is, but that's another story).
The Australian National University's eminent Prof David Chalmers, ranked the 2nd most influential philosopher in the world in a 2013 global survey. Chalmers makes a distinction between "easy" problems of consciousness, such as explaining object discrimination or verbal reports, and the single hard problem, which could be stated "why does the feeling which accompanies awareness of sensory information exist at all?"