Begin by supposing the first alternative: brain generates consciousness. Consciousness being an effect of the material brain’s activity, it therefore must reside exclusively within the living brain. It must, according to this view, cease to exist when the brain dies. We shall explore whether this alternative can be carried via thought experimentation to some reasoned hypothesis that is logical and rational—discovering, as we go, where thinking imaginatively about it may lead us.
As was done with the Big Bang hypothesis, we logically choose to explore backward in time, “de-volving” that which clearly had evolved. Reversing the usual perspective can help us consider material origins – that is, placing consciousness on an evolutionary line between past and future may help us to freshly perceive it as a phenomenon that, like all other evolved phenomena, has both antecedents and consequents. To fairly represent the materialist perspective, we will adhere strictly to an inviolate reductionist axiom: material effects must have material causes.
Under the generator hypothesis, any given person’s consciousness-generating brain necessarily had its origins in a combined genetic inheritance from two parents, both of whom must also have had consciousness-generating brains. Consciousness was DNA-inherent in both the sperm and the egg, being a potential thus transmitted from one generation to the next like all other human potentials. The material cause, consisting of two parents genetically merging and passing down their respective consciousnesses, becomes a unitary material effect in the child.
Each of those parents similarly received a consciousness-containing brain from the genes of two more persons in the grandparent generation—and so on, back and back for tens, hundreds, thousands of generations. In this scenario, each generation’s genetic inheritance of consciousness necessarily had to come from a prior generation, all the way back.
All the way back to…when? About 300,000 years ago our species, Homo sapiens, emerged as one branch (another was our nearest human relative Homo neanderthalis) descended from an ancestor we call Homo heidelbergensis. At that distant time something very like the consciousness we experience today was being passed on, via DNA brain-forming instructions in the genes, from two parents to one offspring, just like today. Material cause, material effect.
Around 800,000 years ago Homo heidelbergensis was evolving out of Homo erectus, who in turn had emerged from a common ancestor of ourselves and our great ape cousins. Assuming the brain (and only the brain) generates consciousness, it follows that there has to be a directly inherited line of connection between the consciousness-generating brain of a modern human and the consciousness-generation brain of that ancient bipedal ancestor. This is axiomatically true because such consciousness as our early ancestors had was (we hypothesize) generated by their brains.
That less-evolved ancient consciousness must have been, in some degree, qualitatively different than modern more-evolved human consciousness, because we observe that the present-day descendants of that ancient common ancestor—ourselves and the great apes—do not have quite the same kind of consciousness as each other. Chimpanzees, bonobos, gorillas and orangutans clearly are self aware, but just as clearly do not have the same quality or “level” of consciousness as humans (or each other), given their respective brain sizes and intellectual abilities. Nevertheless, true to our supposition that consciousness is transmitted by genes that produce brains, every evolved line clear back to homo erectus has to have had some kind of consciousness even if not exactly like ours. The popular assumption, of course, is the larger the brain the “higher” the level of consciousness it generates (notwithstanding that elephants, bottlenose dolphins and three types of whales all have larger brains than ours).
Leapfrogging over eons of time past, we reasonably imagine the most ancient common ancestors of all mammals finding mates and passing on their paired DNA to their offspring. And along with that more primitive version of DNA came more primitive consciousness. Moving faster and further back now, we find the common ancestors of all vertebrates, then invertebrates—all passing on some kind of brain-generated proto-consciousness…of some nature. Dimmer, more primitive, equivalent to the primordial cells that over millions of generations would differentiate and evolve into skin, livers, eyes. But it had to be there, because it got passed all the way down to our modern brains which clearly have it here and now. Those ancient pre-brains (read ancestral neural networks) logically must have generated some kind of pre-consciousness potential—there was nowhere else from which it could emerge. Material effects must have material causes.
Teilhard de Chardin considered such things, observing that “when we finally lose sight of bacteria they are no more than one five-thousandth of a millimetre long.” (Chardin, 1959, p. 92) Yet, for the first primal living cells, he wrote, the elemental particles that formed them are of colossal size compared with the molecules normally dealt with in organic chemistry. Ancestral proto-cellular life would have made its critical transit from physical molecule to living cell when it emerged from mega-molecules, already infinitely complex, into a state of “biological super-tension” that encompassed all the potentials eventually expressed in us, the inheritors, including consciousness.
Thus with inexorable logic we arrive back at the famous (hypothesized) pool of chemical slime, rich with acids and pregnant molecular aggregates which respond to lightning strikes by (presumably) becoming “alive” and then, by some means now unknowable, reproducing themselves in successive virus-like generations. Logically, proto-consciousness of some unknowable potential nature was there too. It had to be, because it is a material effect which could not exist in our modern brains if that originating wetness had not contained some primitive pre- or proto-consciousness that could be passed, evolving all the way, up to us. Material effects must have material causes, as the ever skeptical reductionistic materialists say.
(Note: This example of a thought experiment assumes, without distracting detail, the importance of the phenomenon known as “emergence.” Achieving status as a distinct branch of science only over the past forty years or so, emergence is generally called upon to explain the appearance of complex biological phenomena that are seemingly inexplicable under the “normal” terms of continuous evolutionary selection. Oft-cited examples of such evolved complexity include organs and organic systems whose whole is seemingly different in kind from (or greater than) the sum of their parts, such as eyes, the brain, and even consciousness per se. Emergence thus is sometimes misperceived as being limited to biological significance. The phenomenon in fact applies broadly to all evolutionary mileposts, including cosmic developments, since the Big Bang. Emergence is somewhat the antithesis of the ever-more-reductive specialization which has dominated the modern history of science, in that its perspective points precisely opposite that of reductionism. It does not “reduce,” it emerges—upward. An excellent overview is available in Harold J. Morowitz’s book The Emergence of Everything. Morowitz traces the field’s modern development from C. Lloyd Morgan’s 1923 book Emergent Evolution, and describes twenty-eight major emergences representing, in his words, “a continuous series going from the reductionist core of particle physics to the most noetic aspect of human thought.” (Morowitz, 2002, p. 179) This vast scope of interest will be evident as our thought experiment example now continues.)
Life consciousness in context
Biological evolution is but a subset of the still grander cosmological evolution—a wondrous continuum of self-emerging Creation from the beginning of time to the present moment with no internal boundaries, not one. We thus have reached that dim transition zone where our thought experiment’s backward exploration must cross what Teilhard calls “the secret of the connection between the two worlds of physics and biology.” (Chardin, 1959, p. 79)
That primal pool of slime was formed by the unnamed earth’s natural elements—rocks dissolved by rain, flowing downhill to the pool, minerals geysered up by hot water, oozing over into the pool (albeit, actually, it might have happened in a then-planet-wide ocean). Those ancient elements have to have contained a potential form of proto-consciousness, however slight or different, because they were the elemental precursors of the early life precursor to the evolved human brain of today. We can hardly imagine what that dim ancient pre-consciousness may have been like, but logically there it was, evolving, “emergent.”
Precursor to that—from a big, shrinking ball of hot gas then in this arm of our galaxy—the earth with all its constituent elements was formed along with our sun and its other planets. Proto-consciousness of some nature was there in that gas too, for the logic of evolution is inexorable and material effects must (it is still being hypothesized) have material causes. Whatever it is that emerges and evolves, anywhere, it is said, can only do so from the available source components that were already in place. That’s scientific reductionism at its most fundamental. Fundamentalist, one might call it.
Our solar system contains heavy elements, which tells us it is a second generation star system in the universe’s ongoing evolution. The first generation was mostly hydrogen and helium from which formed the first giant stars, eventually to grow old and explode as supernovas, flinging out heavy elements that would make our eventual existence possible. Potential consciousness of some primal nature had to be there in the hydrogen that made the first stars.
We’re now almost all the way back so let’s float over to the Big Bang, and watch. This primordial (and nonexistent) microscopic dot colossally explodes and within seconds rapidly expands into a major fraction of the infinitely vast universe in which we homo sapiens will eventually emerge, to grow, make love, argue politics, and think. Continuing our dead-on logic, it follows that the Big Bang seeded pre-consciousness of some indefinably potential nature throughout the universe, starting with that famous first trillionth of a second. “Throughout” includes not only the matter and energy that our eyes see and instruments measure, but also the so-called “empty vacuum” out there in the really big spaces between galaxies and their clusters.
Therefore, primal consciousness of some nature thus has to be everywhere in the universe, because we are confronted by the (hypothetically) obvious effect that our consciousness is generated by our brains. Our brains unquestionably got here by evolution, and we know tolerably well the entire route by which they evolved, hence we must reasonably envision the integrally parallel evolution of consciousness.