   Human beings can experience the world in various ways by means of several distinct sensory modalities (vision, audition, touch, olfaction). They are also aware of parts of their bodies as when they suffer pains. The problem of consciousness is often called “the problem of qualia” because states with a strong phenomenal character—like pains, visual or olfactory sensations—are states that introspectively seem endowed with a strong intrinsic subjective quality. The general problem of consciousness is to explain, in Thomas Nagel’s (1974) famous phrase, “what it is like” to be a certain creature with a phenomenal experience. What is the phenomenal character—the phenomenology—of the various forms of human experience? Few if any philosophers—physicalist or otherwise—are inclined to assume that, unlike intentionality, phenomenal consciousness can be exemplified by non-mental things. Not many would deny that, although pains, visual sensations, olfactory sensations, auditive sensations are very different experiences, nonetheless they all exhibit a common property called “phenomenal consciousness”. From both a scientific and a physicalist perspective, the questions arise whether phenomenal consciousness is physical and whether it can be explained in physical terms, i.e., as a result of processes happening in the brain.