There is a drug, cyclophosphamide, which suppresses the immune system. Using it on laboratory rats simultaneously with a drink of saccharine water, the scientists Robert Ader and Nicholas Cohen made an interesting discovery. After three days, they gave the sweetened water alone and found an identical degree of immune-suppression: the rats' immunity had been conditioned to respond to a taste. Extend this to a human subject and you're face to face with the mind-body problem.
Plus or minus the odd deja vu, few of us regard the mind-body problem as a matter of everyday concern. If the organic and the mental belong to different spheres or the same; whether mind is on a higher or a lower plane than body; whether kinetic inter-actions are possible between the two: these questions we are generally happy to leave to specialised philosophy.
But not in medicine. In health, the relation between mind and body is of crucial practical importance, which makes it hard to understand why, ever since the passing of the Galenic system, doctors have traditionally regarded the subject as exotic and raffish, even dangerous. Scientific medicine likes to tread on solid ground; the mind's domain is foggy and swampy. Best to draw a few vague maps marked "autogenic", "idiopathic", "Munchausen Syndrome", "placebo", and then forget all about it.
Now biologist Paul Martin is here to tell us all this has changed. Medical science, he says, has discovered "extraordinary things" in recent years about the mind-body question, of which the rat-work of Ader and Cohen is just a small detail. Martin has read voraciously about newly-proven ways in which the mind contributes to ill-health. The trouble is, along with these "mind-boggling" discoveries, he has found too many ways of muffing the entire project.
In a truly misguided moment, Martin decides to take illustrations from "great literature". But his superficial pages on Heathcliff, Raskolnikov and other literary sickies never justify a decision that is based on the odd belief that fictional case-histories are more exemplary and more "entertaining" than real ones.
Martin's sense of history is equally fallible. Psychosomatic ideas are certainly not new, as he himself notes, but I wish he'd traced their ebb and flow with more precision. Galen, he writes, was a "suprisingly modern" materialist who nevertheless got a lot of things "embarrassingly wrong". Who's embarrassed? Without access to modern knowledge, Galen was a subtle diagnostician and psychologist, whose notion of balance in applied medicine - whether mental or physical - has always been relevant. For a really "modern" type of redneck reductionist, Martin could have looked at the 18th-century figure of La Mettrie, who believed consciousness to be a side-effect of the need to fuel the body's machine, a position that seems pretty close to Martin's own.
It is hard to see the essay-plan to which Martin is working. Giving space over-generously to his obsessions - heart disease, cancer, the immune system and the trendy discipline of "psycho-neuroimmunology" (yes, it exists) - the argument is all out of kilter. Martin is thorough on the biology of "fight and flight", a multiplex stress-response of certain glands and the sympathetic nervous system that is found chronically in "Type-A" individuals and is of well-documented relevance to heart disease. But he ignores other aspects of the endocrine and nervous systems which are equally central to his argument. There is zilch on fertility or hysteria and nothing (of use) on sexual response or the skin, except for a throwaway remark about blushing. Worse, there is no discussion anywhere of pain.
It is an index of how skewed this book is that, despite devoting a chapter to interpersonal relationships and health, its author gives only four superficial paragraphs to the placebo effect and has nothing to say about the most important relationship in all medicine, the one between doctor and patient. Sigmund Freud's ideas are taken rather less seriously in this volume than those of Ian Fleming, yet it was his central belief, in the words of Lacan, that "there are illnesses which speak". The wisely heterodox Oliver Sacks is a great mentor here, carefully positioning doctors in relation to the subjective and objective meanings (or messages) of disease. As well as the responsibility of identification, stresses Sacks, the doctor has an overriding duty to understand.
But understanding is a trap for reductionists, of which Martin ultimately is one. If subjectivity - consciousness - is involved in disease, then an element of responsibility, the patient's collusion, perhaps, in an illness, ought to seep into the diagnosis. But medical correctness cannot face up to this possibility and nor, judging by the way he shrinks from notions of "blame", can this author, leaving many of the most important implications of his thesis unexplored.