David Chalmers is a famous philosopher in the area of philosophy of mind. He is currently Professor of Philosophy and Director of the Centre for Consciousness at the Australian National University. He is best known for his notion of the hard problem of consciousness. David Chalmers is the primary creator of the best bibliography on the study of the mind known as Mind Papers currently with more than 18000 entries. For more information, see his Wikipedia Page.
In 1995, David Chalmers authored a paper entitled "Absent Qualia, Fading Qualia, Dancing Qualia" in which he proposes a principle of organizational invariance which holds that any functional isomorph of a conscious system has experiences that are qualitatively identical to those of the original system as represented in this Functional Equivalence camp in the topic on the 'Hard Problem'.