Thomas Nagel writes: “The appearance of reason and language in the course of biological history seems, from the point of view of available forms of explanation, something radically emergent—if, as I assume, it cannot be understood behavioristically. Like consciousness, it presents problems of both constitutive and historical explanation. It appeared long after the emergence of conscious creatures, yet it also seems to be essentially a development of consciousness and ought to be understandable as part of that history. Like consciousness, reason is inseparable from the physical life of organisms that have it, since it acts on the material provided by perception and natural desire and controls action, both directly and indirectly. Any understanding of it will transform our understanding of physical organisms and their development as well.
“The great cognitive shift is an expansion of consciousness from the perspectival form contained in the lives of particular creatures to an objective, world-encompassing form that exists both individually and intersubjectively. It was originally a biological evolutionary process, and in our species it has become a collective cultural process as well.
“This, then, is what a theory of everything has to explain: not only the emergence from a lifeless universe of reproducing organisms and their development by evolution to greater and greater functional complexity; not only the consciousness of some of those organisms and its central role in their lives; but also the development of consciousness into an instrument of transcendence that can grasp objective reality and objective value.
“Certain things can be assumed, if there is such a thing as reason. First, there are objective, mind-independent truths of different kinds: factual truths about the natural world, including scientific laws; eternal and necessary truths of logic and mathematics; and evaluative and moral truths. Second, by starting from the way things initially appear to us, we can use reason collectively to achieve justified beliefs about some of those objective truths—though some of those beliefs will probably be mistaken. Third, those beliefs in combination can directly influence what we do. Fourth, these processes of discovery and motivation, while mental, are inseparable from physical processes in the organism.
It is trivially true that if there are organisms capable of reason, the possibility of such organism must have been there from the beginning. But if we believe in a natural order, then something about the world that eventually gave rise to rational beings must explain this possibility. Moreover, to explain not merely the possibility but the actuality of rational beings, the world must have properties that make their appearance not a complete accident: in some way the likelihood must have been latent in the nature of things.
“So we stand in need of both a constitutive explanation of what rationality might consist in, and a historical explanation of how it arose; and both explanations must be consistent with our being, among other things, physical organisms. The understanding of biological organisms and their evolutionary history would have to expand to accommodate this additional explanatory burden, as I have argued it must expand beyond materialism to accommodate the explanation of consciousness.
“A reductive account of reason, entirely in terms of the properties of the elementary constituents of which organisms are made, is even more difficult to imagine than a reductive account of consciousness. Rationality, even more than consciousness, seems necessarily a feature of the functioning of the whole conscious subject, and cannot be conceived of, even speculatively, as composed of countless atoms of miniature rationality. The metaphor of the mind as a computer built out of a huge number of transistor-like homunculi will not serve the purpose, because it omits the understanding of the content and grounds of thought and action essential to reason. It could account for behavioral output, but not for understanding.
For these reasons, a holistic or emergent answer to the constitutive question comes to seem increasingly more likely than a reductive one as we move up from physical organisms, to consciousness, to reason. This would mean that reason is an irreducible faculty of the kind of fully formed conscious mind that exists in higher animals.”
Thomas Nagel, Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature is Almost Certainly False (Oxford University Press, 2012), 85-91.
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