Paul Broks sits in a small seminar room surrounded by "rows of display jars containing specimens of human brain, each suspended in a liquid the colour of watery piss". Among them are three which once belonged to the participants in a murderous love triangle. "I love the stillness of this place," he writes, "and the hum of the void - the sense of worlds dissolved and dissipated passions. It fills me with a sense of being. I am not yet pickled meat."
It also causes him to reflect on his work. "My area of supposed expertise, neuropsychology, is the subject about which I feel the most profound ignorance ... Wouldn't it be absurd for an airline pilot to deny knowledge of the principles of flight, or for a physician to claim ignorance of the basics of human physiology and anatomy? Yet I can give no satisfactory account of how the brain generates conscious awareness. Worse still, I find myself edging towards a doubt that it means anything at all to say that the brain generates consciousness."
This, of course, is a celebrated philosophical conundrum usually known as "the mind-body problem": our brains are obviously necessary for consciousness, but what is the precise link between the "flesh and blood and bone and brain" inside our heads and our rich inner life of thought, feeling and fantasy? Some have argued that it is a "category mistake" to try and explain one in terms of the other. A different school, sometimes derided as "Mysterians", believes that we humans will simply never be smart enough to understand the connections. Many have tried to test their views by means of thought experiments featuring "the brain in the vat, the brain transplant, and other science fiction fantasies about teleportation and mind duplication".
Broks's wonderful book is like an extended, rather anguished argument with himself on these issues. A key claim is that some of the people he sees in his clinic, and particularly the split-brain patients, are "thought experiments made flesh". He acknowledges the influence of Oliver Sacks (and Sacks's own model Alexander Luria) in his commitment to a "romantic science" which does justice to the individual patient as well as the neurological syndrome. But he also worries whether "neuro-gothic" tales, whatever their scientific value, owe their appeal to "the intrinsic fascination of the aberrant and the bizarre".
Many of the damaged personalities are very curious indeed. Michael wonders aloud: "Why does raw meat give me a hard on?" Martin is in his late forties but, asked what he's been up to, yells back to the assembled Senior Common Room: "I've been masturbating quite a lot." Maggie is incapable of feeling fear in real life, but reacts violently to mild aggression in a soap opera.
Anthony loses his ability to "read between the lines" in conversation and finds he can deal more easily with straight- talking Australians than the elliptical English. Jeanne draws a complete blank when asked to list some four-legged animals: "For some reason I can only think of three- legged animals."
Perhaps strangest of all are the people suffering from dysexecutive syndromes. One kept stopping, mid-handshake, to pick up a milk bottle, straightened up, turned towards Broks and then bent down again in an endlessly repeating pattern. Another suffered a kind of moral equivalent, a guilt so intense over "a single, weedy act of marital infidelity, a long time ago" that his whole head of hair fell out over a single weekend.
All this makes Broks a worthy claimant to the much contested title of "the new Oliver Sacks", although the flavour of his work is very different. It is hard …