From Bacteria to Bach and Back: The Evolution of Minds

by Daniel C. Dennett

The total weight of all life on the planet now—the biomass—is currently estimated as more than half made up of bacteria and other unicellular “robots,” with “robotic” plants making up more than half the rest. Then there are the insects, including all the clueless termites and ants that outweigh the huge human population celebrated by MacCready. We and our domesticated animals may compose 98% of the terrestrial vertebrate biomass, but that is a small portion of life on the planet. Competence without comprehension is the way of life of the vast majority of living things on the planet and should be the default presumption until we can demonstrate that some individual organisms really do, in one sense or another, understand what they are doing.