The human mind, and sense of self does not emerge purely in response to the growth of an operational brain. It takes healthy, well-functioning gray matter and long term, psycho-social training, learning, nurturing and emotional cultivation in order to create a context in which "the light can switch on" in a human mind. In situations where children with healthy gray matter have been undersocialized, their capacity to develop a self, mind and identity has been severely impaired. So it would seem that, in addition to being a product of the atoms that constitute the human body (nature), the mind is an emergent, "extra" phenomenon that can only coalesce as a result of a long term social-psychological care and interaction (nurture).
Hard determinists are highly skeptical of the idea that the human mind can consist of anything but--or is not reducible to--the activity of the atoms and energy (nature) that constitute the human animal. Once again, Hawking and Mlodinow emphasize their "exclusively nature" position by asserting that the human experience is entirely reducible to, and determined by the physical properties of the human animal's constituent elements:
It is hard to imagine how free will can operate if our behavior is determined by physical law, so it seems that we are no more than biological machines and that free will is just an illusion (Hawking and Mlodinow).It is worth pointing out that Hawking and Modlinow base their assertion on an assumption, "...if our behavior is determined by physical law..." that they fail to demonstrate. While they "concede" that "human behavior is determined by human nature," they also concede that they cannot validate their hypothesis:
...it also seems reasonable to conclude that the outcome is determined in such a complicated way and with so many variables as to make it impossible in practice to predict. For that one would need a knowledge of the initial state of each of the thousand trillion trillion molecules in the human body and to solve something like that number of equations. (Hawking and Mlodinow).The above statement is only "reasonable" for those who embrace a faith-based, superstitious commitment to determinism. Again, the most fundamental and unvarying truth that quantum science teaches is the unavoidable conundrum of quantum uncertainty ( God does play dice with the universe ). It doesn't matter how big one's computer is, or how many billions of years it might take to calculate, there is simply no way to determine, "the initial state of each of the thousand trillion trillion molecules in the human body." It boggles the mind that two eminent physicists would be so unwilling to embrace the full implications of quantum uncertainty. With apologies to Einstein, quantum science has revealed the inescapable truth that determinism is naught but a stubbornly persistent illusion. Unfortunately, the desire to sustain a superstitious conviction in a deterministic universe is so powerful that even the most sophisticated thinkers have occasionally fallen prey to an "exclusively nature" reductionism:
...all ordinary phenomena can be explained by the actions and motions of particles. For example, life itself is supposedly understandable in principle from the movements of atoms, and those atoms are made out of neutrons, protons and electrons. I must immediately say that when we state that we understand it in principle, we only mean that we think that, if we could figure everything out, we would find that there is nothing new in physics which needs to be discovered in order to understand the phenomena of life (Richard Feynman).Whenever scientists make omniscience (i.e., "if we could figure everything out") a precondition for their conjectures, they are, to put it mildly, on the wrong track. Scientists have no business dreaming of a time when they "will know everything" because nothing of the sort will ever happen. Again, the first lesson of quantum mechanics is that it is impossible to know everything about anything--not even a single quantum particle! Omniscience is therefore an unscientific, illogical, erroneous presumption, and no one should have been more aware of that fact than Richard Feynman . As soon as scientists get the idea that they ever can, or ever will know everything, then the scientific truth-seeking process will grind to a screeching halt.