Constraints for Phenomenal Quality Realists
Phenomenal quality realists -- whether they are metaphysical dualists of physicalists who admit only a conceptual dualism -- are very plausibly committed to the existence of sets of neural activation patterns that satisfy the following constraints. (1) Richness. There are thousands of distinct phenomenal qualities, and thus thousands of distinct neural activation states. (2) Modal Segregation. Some series of just noticeable differences will take you from any quality to any other quality in the same sensory modality; but not from a quality in one modality to a quality in another. (3) Location Neutrality. Location as such is never a causal property (although location is sometimes a handy proxy for an efficacious property that is in that location). The present paper both explains the difficulty of providing a set of neural activation patterns that satisfies all these demands, and constructs two solutions that show their mutual satisfaction to be possible. One of these provides a way of identifying distinct "concurrency patterns" by which the same set of firing ratios within a set of neurons may be achieved in different ways. Ratio sets, even for small numbers of neurons, can adquately provide for Richness, while concurrency patterns can provide Modal Segregation; and in neither case is there a violation of Location Neutrality.