[This photo was selected as winner of the 2nd Annual Philosophical Photography Contest hosted by the Rotman Institute of Philosophy at the University of Western Ontario.]

Consider your visual experience as you look at a royal blue wall. There is something it is like for you subjectively to undergo that experience, some phenomenological character that this experience has. There is a “blueness” to the royal blue. This experience is very different from what it is like to experience the “redness” of a ruby red window shutter. This ineffable, intrinsic, private, non-physical subjective experience is called qualia. While there is still debate about how qualia relate to the physical world both inside and outside our minds, the concept remains central to a proper understanding of the nature of consciousness.