Consciousness and Mind (PDF)

Consciousness and Mind presents David Rosenthal's
influential work on the nature of consciousness. Central to that work is
Rosenthal's higher-order-thought theory of consciousness, according to which a
sensation, thought, or other mental state is conscious if one has a
higher-order thought (HOT) that one is in that state. The first four
essays develop various aspects of that theory.

The next three essays present Rosenthal's homomorphism theory of
mental qualities and qualitative consciousness, and show how that
theory fits with and helps sustain the HOT theory. A crucial feature
of homomorphism theory is that it individuates and taxonomizes mental
qualities independently of the way we're conscious of them, and indeed
independently of our being conscious of them at all. So the theory
accommodates the qualitative character not only of conscious sensations
and perceptions, but also of those which fall outside our stream of
consciousness. Rosenthal argues that, because this account of mental
qualities makes no appeal to consciousness, it enables us to dispel such
traditional quandaries as the alleged conceivability of undetectable
quality inversion, and to disarm various apparent obstacles to
explaining qualitative consciousness and understanding its nature.

Six further essays build on the HOT theory to explain various important
features of consciousness, among them the complex connections that
hold in humans between consciousness and speech, the self-interpretative
aspect of consciousness, and the compelling sense we have that
consciousness is unified.

Two of the essays, one an extended treatment of homomorphism theory,
appear here for the first time. There is also a substantive introduction,
which draws out the connections between the essays and highlights their implications.