Books: A wild and crazy Why

The Solitaire Mystery by Jostein Gaarder Secker, pounds 15.99; E Jane Dickson discovers that `esse est percipi' can be fun

Life, Jostein Gaarder repeatedly reminds us, is "a crazy adventure". Readers who are quiveringly sensitive to the word "crazy", with its secondary, Scandinavian meaning of blithe and blameless heartiness, should be warned that they may find the tone of The Solitaire Mystery distressing.

Like Sophie's World, the 1995 publishing smash that turned Gaarder, a former philosophy teacher from Bergen, Norway, into an international guru, this new novel is aimed at "young adults" and rests on the premise that "learning can be fun". Sophie's World was a marvellously accessible exposition of Western philosophy linked by a narrative so shamelessly rudimentary as to be incidental. The structure of The Solitaire Mystery is considerably more evolved, but scarcely more rewarding.

Hans Thomas is a precocious 12-year-old, who journeys from Norway to Greece with his father in search of his mother, who has abandoned family life in order to "find herself". "Why did she have to go away to find herself?" asks Hans Thomas. "My advice to all those who are going to find themselves is they ought to stay exactly where they are." If this seems a startlingly gnomic pronouncement for a 12-year-old, it is considerably easier on the gorge than Hans Thomas in winsome mood, when he plans to "give Dad some peace of mind as a Christmas present".

On their way across the Alps, Hans Thomas is given a magnifying glass by a mysterious dwarf. The glass enables him to read a tiny book which he finds inside a sticky bun. Events in the sticky bun text, an extended allegory of Bishop Berkeley's theory that the world exists only in our perception of it, reflect Hans Thomas's own experience, while his sentimental education is completed by cultural pitstops.

As a teacher, Gaarder is enthusiastic. In his hands, contingency is worked up into something like a miracle: "The chances of one single ancestor of yours not dying while growing up is one in several billion," Hans Thomas is told. "Life is one huge lottery where only the winning tickets are visible."

Gaarder's literary style does him no favours. "Rainbow Fizz" is a sloppily modern name for a drink developed in 1790, and the triumphant conclusion that "we are all dwarfs, gushing with life" just doesn't sound very nice. The central imagery of playing cards, magic drinks and messages in buns is is almost certainly Gaarder's homage to Lewis Carroll, but somehow these images lack dimension and momentum in their new setting.

Gaarder is the least cynical of philosophers. His arguments are all to demonstrate that we are miraculous beings in an infinitely interesting universe. In an intellectual climate fugged by irony, The Solitaire Mystery shows that it is possible to be both high-minded and big-hearted. As an introduction to moral philosophy, that is surely enough to be going on with.