1. The “constitutive problem”: it must explain “the relation” between the conscious mind and the human body and brain [the infamous interaction problem on which substance dualism comes a wreck]; and2. The “historical problem”: it must explain how consciousness could have arisen in the course of the history of the Kosmos.
Wednesday, December 12, 2012
The Nature and History of Consciousness
In Chapter 3, Section 3 of Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False, Thomas Nagel puts the problems that must be solved by any account of the Kosmos (henceforth, K) that includes consciousness (henceforth, C).
The second requirement keeps the problem of C from being “quarantined in the mind”.
Regarding the first, Nagel says in Section 4 that a “constitutive account [of C] will either be reductive or emergent. A reductive account would be, in my terms, an expanded materialism. The material constituents of conscious minds would either have to include some new types of particles, etc., that underlie C, or the existing pallet of materials would have to have properties that are not currently recognized by physics.
An emergent account would look for the explanation of C among the higher order complexities of organisms. I offer the following analogy. Mass is reductive property of atoms. The mass of larger objects is the sum of the combined mass of the constituent particles. Wetness is an emergent property of hydrogen and oxygen atoms. Only when combined into molecules of water, and perhaps only when there are a lot of the latter together.
Nagel thinks that the reductive account is the more radical of the two and this seems right. It would require a revision of the most fundamental levels of physical theory. He thinks that an emergent account seems too much like magic, for he finds the analogy with liquidity faulty. I do not quite understand why he is convinced of that, except that the metaphysical distance between atomic properties and material properties seems much less than that between dead matter and conscious brains.
He also thinks that, since organisms are composed of the same stuff that everything else is, then everything else (i.e., all material particles) must have hidden properties that might enable consciousness if indeed this account is correct. This strikes me as going too far. Maybe only some elements have the proto-conscious properties, just as only some are radioactive.
When he turns to the Kosmic history of C (Section 5), he suggests three possible approaches: efficient causation, teleology, and intention. The first two map neatly with two traditional theories of evolution: that it is driven by blind, mechanical forces (the only scientifically respectable approach at present) or that the evolution of life on earth is driven by some intrinsic program analogous to the genetic programs that drive the development of an individual organism. The third approach points, of course, to something like a creator God.
Section 5 is rather difficult. Nagel here critiques the first approach. As in the case of the constitutive problem, both an emergent and a reductive interpretation are logically possible.
According to the former, the history of the universe up to the emergence of conscious organisms may be thoroughly physical and reductive. After that point, the history of K must contain both the physically reductive stuff and the non-physical phenomenon of C. That does the least damage to the standard physical picture, but also seems to render the emergence of C inexplicable. What was it about the physical K that rendered the emergence of C likely at a certain point in time?
A reductive account of the history of C would have to show that
The propensity for the development of organisms with a subjective point of view must have been there from the very beginning, just as the propensity for the formation of atoms, molecules, galaxies, and organic compounds must have been there from the very beginning, in consequence of the already existing properties of the fundamental particles.
That is a tall order. Astronomers and physicists can model how simple elements give rise to more complex ones through the formation of stars and destruction of stars due to the properties already inherent in the simple elements. In principle, one might have predicted the history of K from its nature at the point when there was nothing but hydrogen to work with. By contrast, what is there in the history of the physical materials that would lead one suspect the eventual development of C?
In the case of physical phenomena, we have a good grasp of the relationship between parts and wholes, matter and form. We have as yet no comparable grasp of the relationship between parts and particles in the brain and the phenomenon of C.
So far, this seems to me correct as an analysis of how difficult the problem of a comprehensive physics would be. Nagel then goes on to argue that the proto-psychic properties of matter in a reductive account would have to be part of the explanation of the appearance of life. Such properties would have to explain not only how C is selected for once conscious organisms are in operation, but how such properties underlie the appearance of such organisms in the first place.
This is unclear to me. The physical nature of hydrogen can explain the production of metals after stars begin to blow the hell up. The nature of iron is not necessary to explain the appearance of iron.