David M. Rosenthal (philosopher) - Quality-space Theory

Quality-space Theory

Since mental states are conscious only if one is aware of those states, every mental state can occur without being conscious. That includes states that exhibit mental qualities, such as the perceptions and bodily sensations that occur in subliminal perception and in blindsight. This view goes against many contemporary views, on which mental qualities are tied inextricably to consciousness. So Rosenthal has developed a "quality-space theory" (also "homomorphism theory") of the mental qualities, which explains what qualitative mental states without appeal to consciousness. All mental qualities are individuated by their positions in a quality space that pertains to their sensory modality. More specifically, we can define a quality space of the physical perceptible properties that mental qualities enable access to, relying just on the ability to discriminate among those perceptible properties. Mental qualities, then, are the properties of mental states that make that discriminative capacity possible; so they are fixed by the positions they occupy in a quality space corresponding to the quality space of accessed perceptible properties. Because the quality spaces of perceptible properties are determined solely by the ability to discriminate among sample properties, independently of whether the perceptual states are conscious, mental qualities themselves can occur without being conscious. They occur consciously only when one is aware of oneself as being in the relevant qualitative state, on the HOT theory, when one has the relevant HOT.