Nagel's classic article "What Is It Like to Be a Bat?" first sets out the problem of phenomenal consciousness. It is an extremely difficult problem.
Setting Out the Problem
Phenomenal Consciousness is essentially the subjective character of experience. That is, phenomenal consciousness is what it is like to have this or that experience.
"[F]undamentally an organism has conscious mental states if and only if there is something that it is like to be that organism--something it is like for the organism."
Consider, for example, the bat. If the bat has phenomenal consciousness, then there is something it is like to be a (particular) bat. But that something is wholly inaccessible to us.
There are facts accessible only from the first-person point of view of the organism. These facts are the subjective facts of phenomenal experience.
Materialism (Physicalism) proposes that every mental event is a physical event. Reductive Materialism proposes that all the facts about mental events can be accounted for by facts about physical events.
The Problem
| 1 | If Reductive Materialism is true, then any fact of mental events can be explained in terms of facts about the physical events on which they supervene. | ||
| 2 | It is not the case that any fact of mental events can be explained in terms of facts about the physical events on which they supervene. | ||
| ∴ | 3 | Reductive Materialism is not true. | 1&2 |