Last fall, a few days before Halloween and about a month after the publication of Mind and Cosmos, the controversial new book by the philosopher Thomas Nagel, several of the world’s leading philosophers gathered with a group of cutting-edge scientists in the conference room of a charming inn in the Berkshires. They faced one another around a big table set with pitchers of iced water and trays of hard candies wrapped in cellophane and talked and talked, as public intellectuals do. PowerPoint was often brought into play.
The title of the “interdisciplinary workshop” was “Moving Naturalism Forward.” For those of us who like to kill time sitting around pondering the nature of reality—personhood, God, moral judgment, free will, what have you—this was the Concert for Bangladesh. The biologist Richard Dawkins was there, author of The Blind Watchmaker, The Selfish Gene, and other bestselling books of popular science, and so was Daniel Dennett, a philosopher at Tufts and author of Consciousness Explained and Darwin’s Dangerous Idea: Evolution and the Meanings of Life. So were the authors of Why Evolution is True, The Really Hard Problem: Meaning in a Material World, Everything Must Go: Metaphysics Naturalized, and The Atheist’s Guide to Reality: Enjoying Life without Illusions—all of them books that to one degree or another bring to a larger audience the world as scientists have discovered it to be.
Contemporary philosophers have a name for the way you and I see the world, a world filled with other people, with colors and sounds, sights and sensations, things that are good and things that are bad and things that are very good indeed: ourselves, who are able, more or less, to make our own way through life, by our own lights. Philosophers call this common view the “manifest image.” Daniel Dennett pointed out at the conference that modern science, at least since the revelations of Darwin, has been piling up proof that the manifest image is not really accurate in any scientific sense. Rather science—this vast interlocking combine of genetics, neuroscience, evolutionary biology, particle physics—tells us that the components of the manifest image are illusory.
Color, for instance: That azalea outside the window may look red to you, but in reality it has no color at all. The red comes from certain properties of the azalea that absorb some kinds of light and reflect other kinds of light, which are then received by the eye and transformed in our brains into a subjective experience of red. And sounds, too: Complex vibrations in the air are soundless in reality, but our ears are able to turn the vibrations into a car alarm or a cat’s meow or, worse, the voice of Mariah Carey. These capacities of the human organism are evolutionary adaptations. Everything about human beings, by definition, is an evolutionary adaptation. Our sense that the colors and sounds exist “out there” and not merely in our brain is a convenient illusion that long ago increased the survival chances of our species. Powered by Darwin, modern science proceeds, in Dennett’s phrase, as a “universal corrosive,” destroying illusions all the way up and all the way down, dismantling our feelings of freedom and separate selfhood, our morals and beliefs, a mother’s love and a patient’s prayer: All in reality are just “molecules in motion.”
The most famous, most succinct, and most pitiless summary of the manifest image’s fraudulence was written nearly 20 years ago by the geneticist Francis Crick: “ ‘You,’ your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. Who you are is nothing but a pack of neurons.”