Ian Hacking reviews The 21st-Century Brain: Explaining, Mending and Manipulating the Mind by Steven Rose, in the London Review of Books:
Steven Rose is a well-known public scientist who has dedicated his career to the study of brains. He has lived through the early days of the technical revolution that has involved increasingly powerful ways of imaging activity in the brain. But he is first of all a biologist. His guiding principle is that we cannot understand the human brain unless we understand how it came into being. He takes as his motto ‘Nothing in biology makes sense except in the light of evolution.’ That is the title of a spirited 1973 polemic against creationism by one of the great evolutionary geneticists, Theodosius Dobzhansky (1900-75).
The maxim suggests two ways of thinking about brains. One is implied directly: start at the beginning of life itself, tracing the appearance of more and more complex living creatures, some of which develop organs that better and better perform brain-like functions. This evolutionary story allows us to begin to understand the constraints governing the structure of complex brains, including our own. The design problems are fascinating: the ways that the different intercommunicating organs within the brain can be made to fit into a skull; which evolutionary paths were followed to end up where we are; and which paths lead to other viable animals. A good deal of the early part of the evolutionary story can be no more than plausible speculation, but whether or not Rose’s speculations are sound, they serve to organise information and understanding in a helpful way.
A second method is implied indirectly by Dobzhansky’s maxim. We should start at the beginning of the life of a human being, and trace the way that an egg becomes a person.