PSYCHOLOGY: Making light of darkness visible

THIS YEAR, 1995, marks the 60th anniversary of fluorescent light. I mention this only because it is one of the few events in the brief history of man's victory over darkness that A Alvarez has omitted from his wide-ranging, often intriguing accou nt of night and its meanings.

In his preface Alvarez likens his research to "pulling out a conjurer's handkerchief: one thing leads to another in an unending, outlandish chain". The analogy holds good for the book, which is constructed with considerable cunning. A history of artificial light, from the first fire-making to electric streetlamps, provokes thoughts on lighting in Caravaggio and the uses of darkness in Shakespeare. An account of the author's terror of the dark in childhood, unremarkable in itself, introduces m editationson the more general association between darkness and evil and on Bruce Chatwin's theory of Dinofelis, a predator that specialised in hunting primitive man. Alvarez's range is extremely impressive.

That holds true not only in terms of subject-matter, but also in manner. There is the autobiographical vein already noted: elsewhere he tells us how his fear of darkness has, paradoxically, been replaced by an obsession with sleep. There is tremendous literary expertise: he offers persuasive readings of Coleridge and Stevenson, who both made intensive use of dream material. He also gives us the first-person reportage familiar from his earlier non-fiction books, attending a NHS sleep clinic as an observer and then as a participant, passing sleepless nights on a mountain and in a rural cottage in Italy and going on patrol with the police.

These approaches are not much help, however, in the core of the book, which is concerned with dreaming. Dreams are both a measurable neurophysiological event and a window into the mind, packed with personal imagery. Putting aside his habitual allusiveness in favour of straightforward exposition, Alvarez uses both aspects to provide a way into a discussion of that modish area, consciousness. Rather than engineer a head-on collision between Freud, the great interpreter of dreams, and the scientific method(a stunt we have all seen too many times), Alvarez gently tries to align two extremely abstruse schools: the post-Freudian "object-relations" school of psychoanalysis and recent thinking in neurophysiology. "From the outsider's point of view, their subtleties blend together and the state of one art illuminates the state of the other," he says.

That's a promise that is not quite redeemed, but the argument, which extends over about half the book's total length, is fascinating. In Alvarez's account, 40 years of research into REM sleep, the period of rapid eye movement that accompanies dreaming, has revealed that the brain is a "closed loop", as busy then as it is while awake. The difference is that the feverish activity of the dreaming brain operates on its own memories rather than on sensory input, and does so without benefit of the analytical tools it normally uses to make sense of the world. This, Alvarez suggests, is the reason for the alarming and chaotic nature of dream experience.

The neurophysiologists, though, offer little help on the interpretation of dreams, a practice shown here to be as old as mankind. After a comprehensive and fascinating account of the history of dream interpretation, acknowledging Freud's intellectual persistence while enumerating his obvious errors, Alvarez moves on to the post-Freudians, picking out Melanie Klein's belief that dreaming is "as continuous in the mind as digestion is in the body". He finds in this "a picture of mind very similar to the `closed-loop' system of the modern neurophysiologists".

This is an intriguing thought, although some would argue that the closeness of the ideas is only the closeness of two halves of an analogy. It is at this point that the stately progress of Alvarez's argument comes to an abrupt end. Instead, he digresses into chaos theory, hypnagogic hallucinations - the jumbled thoughts which sweep over us as we slip from consciousness - and problem-solving during sleep.

Alvarez is an admirable companion through these difficult areas, but the eagerness with which he turns away from them suggests a certain diffidence about material that is not rooted in his own experience. He turns back into a chapter of lacklustre reportage, with an account of night shifts spent on patrol with the New York and London police forces that tells us nothing we have not read before. And that seems an odd way to round off a book that is otherwise packed with extraordinary ideas and perceptions.