Books: Imbiber at the fountain of fantasy

Futuristic fantasy; Wellsian dystopia; satire-cum-soul searcher; mantric realism - whatever Peter Ackroyd's new book may be, it cannot go out and take its place in the world, as the jacket declares it, as a "novel". If not for any other reason than that, in a literary Magimix age where fiction and biography melt the borderlines of fact and invention, and the coming of the virtual age promises us eternal uncertainty, there is nothing novel to be found in this reconstruction of a future from the distant past. The characters have been here before. The hero, donning an orator's mask, bears the name Plato. The fragments of a long-dead world he investigates are recognisably a part of the world of Peter Ackroyd - that is to say, London.

The Plato Papers is set circa 4000 AD. Plato instructs, in a series of dialogues, on the quality of life in vanished ages. First, there was the Age of Orpheus (3500 BC-3000 BC); then the Age of the Apostles (3000 BC-1500 AD); then the Age of Mouldwarp (1500 AD-2300 AD).

He performs, or orates upon, the way of life in these distant days; and it is disconcerting to have the story of Orpheus solemnly recounted, as if in a book for children, until the point begins to show itself in the tone and information provided. The remains of Cerberus have been dug up and can be visited; tourists from this unimaginable age 2,000 years hence may visit the mythic past. What is imagined is as "real" as what is concrete.

This way of thinking and writing was, of course, brought most interestingly to our shores by Jorge Luis Borges in the early 1960s, and it seems a pity that Ackroyd, an imbiber at the dream/reality fountain, should not have acknowledged him in this odd, superficial fable. A time when statues walked and stones could feel - there's a touch of Materlinck, even Barrie here too, and Borges could be forgiven for getting testy at the comparison.

Plato is at his best when investigating the need for pain and guilt in previous ages. From the Age of the Apostles comes a true blast of wonderment at the human capacity for self-torture. Examining the Age of Mouldwarp, our brave orator, picking over the detritus of our over-oestrogenised world, is staggered by the consumer society - though he manages, through sheer ineptitude at times, to misread the words and place names of the long-destroyed city. Mouldwarp, dominated by "webs", and "nets", succumbed finally to the greed and pointlessness of a world where reading about and seeing the misfortunes of others was clearly the major pastime. And after Mouldwarp, when the stars - these, too, a product of the imagination of those who gazed at them - went out, to be followed sharply by the sun, there was, predictably, a long period of darkness.

Light was restored in 3400, and about 600 years later a new "enlightened" type strides the earth. These new children of a world without darkness have no interest in the forgotten ages, and the crux of The Plato Papers resides in a question meaningful to those familiar with the dialogues the first Plato wrote around the great teacher Socrates. Does his curiosity about the secrets of the human psyche infect the young, remove innocence from these new denizens of light? Is Plato, by delving into the tarnished past, corrupting those without the need to know?

The answer is dressed up in jokes, some at cracker-filler or fortune cookie level, for those who respond to this type of humour. We are supplied with a facetious glossary, to assist our time travel. ("Language laboratory; a sterile area where language was created under strict experimental conditions. Opening night: a reference to the creation myth of Mouldwarp, in which the universe is believed to have emerged from darkness and chaos; it was of course a theory that reflected the shadowy violence of the civilisation itself ... Organ grinder: a kind of butcher. See organism.") This spoof of Flaubert's brilliant little Dictionnaire des Idees Recues sits strangely alongside the routine between Plato and "Soul", the straight man of the two, and their musings, questions and answers.

Sometimes Plato's wit and powers of invention dazzle his listeners. On the whole, though, a defaced work by Charles Darwin being attributed to Charles Dickens, the theory of evolution a proof of "comic genius", is as inspiring as the supposition that Sigmund Freud is really a misspelling for Fraud. The tantalising traces of a lost London are what Ackroyd explores well. Perhaps, some time in the far future, his list of commissioned works will come to an end (see "Advance, Large") and he will return to the bones and rivers of the city he loves to depict.