In the previous post (Part I), we met some aliens that seem to have developed a turbo-charged neuroscientific theory of consciousness. Unfortunately for the materialist, the aliens’ story seems incomplete in a way that the antimaterialist can exploit as follows:
While impressive, the aliens’ story leaves out the most essential aspect of consciousness: subjective experience. They make no mention of the fact that there is something it is like for the cats to be smonscious. From the standpoint of the alien theory of brain function, subjective experiences constitute an additional unpredicted fact about the cats. But we know that experiences exist, so any theory that leaves them out is incomplete.
Put bluntly, instead of constructing a theory of consciousness, the aliens stand in complete ignorance of its existence. This is no subtle shortcoming.
Materialists will try to neutralize this concern by claiming that subjectivity is identical to smonsciousness, that these are merely two ways of conceiving of the same property. That is, the alien story highlights a conceptual gap between brains and experiences, but does nothing to support the antimaterialist metaphysical position.
While this standard ‘two concepts/one property’ move technically preserves the logical possibility of materialism, to say the alien story does no harm against materialism verges on disingenuous. In that inductive space of what is reasonable and probable, rather than merely logically possible, materialism takes a serious hit when it runs into our alien friends. Materialists should be deeply dissatisfied that someone could have a complete understanding of the cat’s brain yet be ignorant of consciousness.
Especially given their default tendency to fetishize the natural sciences, materialists should be troubled that they are forced into a position with no clear precedent in the natural sciences. In that context, their response smacks of special pleading, an ad hoc reaction to an obvious shortcoming rather than the organic outgrowth of a positive naturalistic theory.
The materialists might counter by saying that such scenarios actually have many analogous precedents in the natural sciences. Scientists often study the higher-level feature of a system (e.g., heat/patterns of inheritance) and then only later discover its lower-level basis (e.g., mean kinetic energy/genes). The aliens could be implementing the converse scenario, studying the lower-level details of cat brains, but not examining the higher-level (conscious) features. This would be like studying the individual particles in a gas without ever coming to know the higher-level statistical property we know as temperature. This is epistemically interesting, but carries no obvious metaphysical punch.
Unfortunately, by hypothesis the aliens have complete knowledge of cat brains at every level of organization, so this ‘levels defense’ fails. The most apt analogies are actually damning to materialism. Saying our aliens have left nothing out is like saying a physicist has given a complete account of Mercury’s orbit even though he doesn’t know what it means for a planet to revolve around a star; or that a botanist can know everything about plant reproduction even if he has no idea what pollen is. In such cases, the researcher’s story patently overlooks an essential ingredient. The burden of proof would clearly be on the advocate of the physicist/botanist to show that the primae facie appearance of metaphysical incompleteness is mistaken (e.g., that it is merely conceptual). The same applies for our alien scenario.
Our vituperative antimaterialist makes some interesting points. Some are true, some questionable. How should the materialist respond? This post is already too long, so I will defer posting Part III for a couple of weeks [ahem–make that a year].
Note: This scenario was inspired partly by Sellars’ historical fiction involving ‘our Rylean Ancestors’ in his Empiricism and the Philosophy of Mind (1956). [Note added 9/4/12: More obviously it is influenced by the usual suspects (Chalmers, Jackson, Levine, and others who have pushed on the apparent gap between knowledge of brains and first-hand knowledge of experiences).]