 Even more than the nature and unity of conscious awareness, certain seeming intrinsic characteristics—so-called “qualia”—of conscious states have seemed to many to require an anti-physicalist ontological account. The way a patch of redness appears in one’s visual field, or the sound of a trumpet note in one’s auditory field, do not seem to admit of characterization in terms of neural processes within the visual and auditory cortex. Rather, such experiential qualities seem to be distinctive in kind, engendering a mismatch with the physical-structural or functional kinds posited by physical theories, and to have a degree of simplicity that is incongruent with the massive physical complexity of the associated physical processes. (For two much-discussed arguments from these apparent characteristics of conscious experience to at least a modest form of physical-mental dualism, see Jackson 1982 and  entry on qualia and the knowledge argument;  and Chalmers 1996 and  entry on zombies.)