The doubt that consciousness is nonphysical is much stronger:chewybrian wrote: ↑June 24th, 2018, 4:53 amAgain, none of this is intended to 'prove' consciousness is not physical, but only to show that you can not, have not proven that it is, and that there is considerable doubt.
"How could a nonphysical property or entity suddenly arise in the course of animal evolution? A change in a gene is a change in a complex molecule which causes a change in the biochemistry of the cell. This may lead to changes in the shape or organization of the developing embryo. But what sort of chemical process could lead to the springing into existence of something nonphysical? No enzyme can catalyze the production of a spook! Perhaps it will be said that the nonphysical comes into existence as a by-product: that whenever there is a certain complex physical structure, then, by an irreducible extraphysical law, there is also a nonphysical entity. Such laws would be quite outside normal scientific conceptions and quite inexplicable: they would be, in Herbert Feigl’s phrase, 'nomological danglers.' To say the very least, we can vastly simplify our cosmological outlook if we can defend a materialistic philosophy of mind."
(Smart, J. J. C. "Materialism." Journal of Philosophy 60, no. 22 (October 1963): 651-662. p. 660)
An extremely plausible principle can be derived from Smart's statements:
Whatever naturally arises/emerges from or is naturally caused/produced by (nothing but) physical entities is physical itself.
"Three (nonapodictic) reasons might be offered in support of the hypothesis [that consciousness is a state of matter]. First, it is hard to see what else consciousness could be. Consciousness exists in a world of matter/energy, not outside of that world (as God and his angels might be supposed to exist), and depends essentially on (other) forms of matter, causally and otherwise. Given that Cartesian dualism has daunting problems, and is not even clearly intelligible, there doesn't seem much of an alternative to supposing mind to be in some way a modification of matter; the question is, in what way. What we really want to know, in thinking about the mind-body problem, is how it is possible for consciousness to be what we know that it must be. What kind of materialism (if we must use the term) is defensible? Put differently, consciousness must be an aspect of the same world that (other) forms of matter are also aspects of, notably the brain. Organisms are modes of matter, with some distinctive properties, and consciousness is a biological property of organisms; so it is only natural to assume that consciousness too is a form of matter. To say that it is a form of an 'immaterial' substance is to fly in the face of the obvious truth that consciousness is part of the world of embodied organisms—not a separate parallel world, with strange causal connections to the regular corporeal world. There is really nothing else for consciousness to be a mode of than the very stuff that everything else is a mode of.
Secondly, conservation laws in physics preclude the idea of a radically new kind of stuff, energy or matter, coming into existence. So when consciousness came to exist, no new substance was added to the world: old stuff simply took on a new form. Descartes' dualism violates conservation, since extra causal powers—extra energy—are introduced by the injection of mind into the world. His immaterial substance is an independent source of energy and hence motion, so that conservation is bluntly violated. A better view is that pre-existing matter takes new forms in cosmic history—from galaxies to organisms—and consciousness must itself be a form of what existed earlier. But there must be a fundamental constancy in the underlying substance of the world, whatever that may be: so consciousness must be a variant on this substance, not a new type of substance.
Energy is plausibly the fundamental conserved substance, so consciousness has to be a form of energy—a form of the very same thing that electricity and mass are forms of. Moreover, energy in its various forms can be transformed into mental energy—as when the chemical energy in food (deriving from solar energy) is converted into causally efficacious acts of will and other mental work. The energy that powers the mind is nothing other than the energy that exists in various physical forms; and so it is plausible to suppose that the mind itself is a manifestation of that energy. Certainly, the electromagnetic energy of the brain has everything to do with the energy exhibited by the mind, i.e., its ability to do work. The world we observe is a world where conservation is the norm—where nothing fundamentally new comes to be. Novelty comes from recombination, not from new basic realities. Similarly, when consciousness fades away, nothing basic goes out of existence; rather, it changes form—going back to material forms of other kinds. Such continuity suggests that consciousness is just matter/energy in one of its many guises. Kinds of matter/energy can go out of existence, or be created, but the underlying stuff stays constant—as when particles change into other kinds of particles or electrical energy converts to kinetic energy. And the same is true of the kind of matter/energy we call consciousness. Consciousness is a temporary form that universal matter/energy has taken, along with other forms.
Third, and connected, the big bang contained all the materials for generating the universe from then on. New particles came to be in the first few moments, and new forces too, but everything had to be implicit in the initial super-hot plasma: everything that followed had to be a form of what was there at the start. All novelty works with the raw materials of the primal singularity (just as the big bang itself had to be a conservation of what was there earlier). But if so, then consciousness must be somehow implicit in the big bang too: it must be a working out of the matter/energy there at that instant, like planets and organisms. Some of what is new is mere recombination (this is probably true of organisms, now that the élan vital has lost its appeal), and some of it consists in new forms of what was there earlier (were gravitation and electric charge explicitly present at the very earliest stages?). But nothing we see in the universe now belongs to neither category: so consciousness must be one or the other—and the recombination view is not credible. Consciousness must be a new form of the stuff that was present in the first moments of the universe—one of the modes of which matter is capable. There was no ghostly parallel big bang in which immaterial stuff was minted, with consciousness a form of that: consciousness had to have its origin in the very event that originated all the matter of the universe. If we think of the history of the universe since the first moments of the big bang as a process of differentiation in matter, then consciousness is one of the many ways in which matter came to be differentiated—and clearly it specializes in such differentiation. Matter is nothing if not protean."
(McGinn, Colin. "Consciousness as a Form of Matter." In Basic Structures of Reality: Essays in Meta-Physics, 175-191. New York: Oxford University Press, 2011. pp. 179-81)
, the problem is finding ways to get further than that. Which is where our usual methodoloogy, our scientific model and toolkit, seems to fall short. 
