Thanks to the many excellent popularising science books now available, non-scientists can witness the unfolding sagas of the five currently most exciting and important sciences – genetics, particle physics, brain research, palaeoanthropology and astronomy. This is as it should be. The more scientific literacy there is, and, with it, understanding of the aims, successes and limitations of science, the better.

But this important business of communicating science to non-scientists carries one small danger, which is that here and there a scientist will, while popularising his or her subject, try to engage in front-line speculation by offering solutions to one of that particular science’s Big Puzzles. In general, the bigger the puzzle and the further away science is from solving it, the more speculation there is about it in popular books; so if a general reader is offered a solution to the problem of consciousness, or the origin of life, or the fundamental structure of matter, he can be certain that neither its author nor anyone else in the associated scientific community is anywhere near an answer.

This is the case with Susan Greenfield’s book about the brain, in which she asserts (as opposed to argues or demonstrates) that emotion is the basis of consciousness, while at the same time being the antagonist of mind in the sense that an increased level of emotion results in decreased