From Bacteria to Bach and Back: The Evolution of Minds by Daniel C. Dennett Norton, 476 pp., $28.95

For fifty years the philosopher Daniel Dennett has been engaged in a grand project of disenchantment of the human world, using science to free us from what he deems illusions—illusions that are difficult to dislodge because they are so natural. In From Bacteria to Bach and Back, his eighteenth book (thirteenth as sole author), Dennett presents a valuable and typically lucid synthesis of his worldview. Though it is supported by reams of scientific data, he acknowledges that much of what he says is conjectural rather than proven, either empirically or philosophically.

Dennett is always good company. He has a gargantuan appetite for scientific knowledge, and is one of the best people I know at transmitting it and explaining its significance, clearly and without superficiality. He writes with wit and elegance; and in this book especially, though it is frankly partisan, he tries hard to grasp and defuse the sources of resistance to his point of view. He recognizes that some of what he asks us to believe is strongly counterintuitive. I shall explain eventually why I think the overall project cannot succeed, but first let me set out the argument, which contains much that is true and insightful.

The book has a historical structure, taking us from the prebiotic world to human minds and human civilization. It relies on different forms of evolution by natural selection, both biological and cultural, as its most important method of explanation. Dennett holds fast to the assumption that we are just physical objects and that any appearance to the contrary must be accounted for in a way that is consistent with this truth. Bach’s or Picasso’s creative genius, and our conscious experience of hearing Bach’s Fourth Brandenburg Concerto or seeing Picasso’s Girl Before a Mirror, all arose by a sequence of physical events beginning with the chemical composition of the earth’s surface before the appearance of unicellular organisms. Dennett identifies two unsolved problems along this path: the origin of life at its beginning and the origin of human culture much more recently. But that is no reason not to speculate.

The task Dennett sets himself is framed by a famous distinction drawn by the philosopher Wilfrid Sellars between the “manifest image” and the “scientific image”—two ways of seeing the world we live in. According to the manifest image, Dennett writes, the world is

full of other people, plants, and animals, furniture and houses and cars…and colors and rainbows and sunsets, and voices and haircuts, and home runs and dollars, and problems and opportunities and mistakes, among many other such things. These are the myriad “things” that are easy for us to recognize, point to, love or hate, and, in many cases,…