The history of science is partly the history of an idea that is by now so familiar that it no longer astounds: the universe, including our own existence, can be explained by the interactions of little bits of matter. We scientists are in the business of discovering the laws that characterize this matter. We do so, to some extent at least, by a kind of reduction. The stuff of biology, for instance, can be reduced to chemistry and the stuff of chemistry can be reduced to physics.
Thomas Nagel has never been at ease with this view. Nagel, University Professor of Philosophy and Law at New York University, is one of our most distinguished philosophers. He is perhaps best known for his 1974 paper, “What Is It Like to Be a Bat?,” a modern classic in the philosophy of mind. In that paper, Nagel argued that reductionist, materialist accounts of the mind leave some things unexplained. And one of those things is what it would actually feel like to be, say, a bat, a creature that navigates its environment via the odd (to us) sense of echolocation. To Nagel, then, reductionist attempts to ground everything in matter fail partly for a reason that couldn’t be any nearer to us: subjective experience. While not denying that our conscious experiences have everything to do with brains, neurons, and matter, Nagel finds it hard to see how these experiences can be fully reduced with the conceptual tools of physical science.
In Mind and Cosmos, Nagel continues his attacks on reductionism. Though the book is brief its claims are big. Nagel insists that the mind-body problem “is not just a local problem” but “invades our understanding of the entire cosmos and its history.” If what he calls “materialist naturalism” or just “materialism” can’t explain consciousness, then it can’t fully account for life since consciousness is a feature of life. And if it can’t explain life, then it can’t fully account for the chemical and physical universe since life is a feature of that universe. Subjective experience is not, to Nagel, some detail that materialist science can hand-wave away. It’s a deal breaker. Nagel believes that any future science that grapples seriously with the mind-body problem will be one that is radically reconceived.
As Nagel makes clear in the subtitle of Mind and Cosmos, part of what he thinks must be reconceived is our reigning theory of evolutionary biology, neo-Darwinism. Neo-Darwinism maintains, or at least implies, that the origin and history of life can be explained by materialist means. Once the first life arose on earth, the fate of the resulting evolutionary lineage was, neo-Darwinists argued, shaped by a combination of random mutation and natural selection. Biological types that survive or reproduce better than others will ultimately replace those others. While natural selection ensures that species constantly adapt to the changing environments around them, the process has no foresight: natural selection responds only to the present environment and evolution cannot, therefore, be aiming for any goal. This view, Nagel tells us, is “almost certainly false.”
Read more at New York Times Review of Books.