October 11, 1998|By MICHAEL PAKENHAM

Jostein Gaarder wrote that "to wonder about life is not something we learn, it is something we forget." We forget, of course, at the peril of letting our heads turn to Mallomars. If you doubt the exhilaration of exercising the mind, spend a couple of hours with "The Number Devil:

A Mathematical Adventure," by Hans Magnus Enzensberger (Metropolitan/Henry Holt, 263 pages, $22).

The book's purpose, I think, or anyway its effect, is to take the mind for a fast romp, and prove that with a bit of exercise it can climb trees and leap roaring torrents.

It is irresistible to compare it with Gaarder's own "Sophie's World: A Novel About the History of Philosophy," (Farrar, Straus and Giroux, 403 pages, $19), which came out in the United States in 1995. Before that, "Sophie's World" was the best seller in Norway, Denmark and Britain and high on the market in 33 other countries. It didn't do particularly well in this country.

Gaarder's point about wondering is perhaps the most enchantingly insightful and demanding statement of that whole charming book. But there is much more. But back to mathematics:

In the new book, the number devil, an off-duty mathematician who begins as the size of a grasshopper but usually appears in human dimensions, turns up in a dream of a 12-year-old boy named Robert. The young man detests mathematics, reviles his disgustingly fat and ill-mannered real-life mathematics teacher and with moral certainty knows all homework to be child abuse.

The devil himself is a tendentious, short-tempered, occasionally ridiculous know-it-all. His redeeming genius is that he is absolutely certain that mathematics is simple and requires next to no competence with arithmetic and that the whole enterprise is delightful. And, what's best: "Most genuine mathematicians are bad at sums."

He returns for 11 other nights. Those 12 dreams constitute the entire book. By the end, I knew more about mathematics than I had known before.

Rich and delicious

More impressively, I knew I had just read one of those rare and glorious children's books that is much too rich and delicious to be wasted on children. Unless you happen to be a child. Of course, books like this have a way of making clear that childhood has enormous advantages over being grown up.

Enzensberger is a 69-year-old German poet, critic, editor, journalist and professor. He has written a number of other books, including at least four sold in America: "The Consciousness Industry," "Europe, Europe," "Politics and Crime" and "The Sinking of the Titanic."

Among fans, he is known as one of the few people scribbling who has a genuine claim to the title polymath, yet he consistently writes with polished-crystal clarity. "The Number Devil" became the best selling book in Spain and rose high on the charts in Germany, Italy and other countries.

If you convened a coven to invent a name for somebody to write utterly authoritative - and completely incomprehensible - stuff about dreaded math, what would it come up with? Well, Einstein's been used up. Jones? MacFarquarharh? No. Nowhere near right. Ah! Hans Magnus Enzensberger. Perfect!

But no. It's not incomprehensible. Not for a minute.

Do you know or remember what the Fibonacci sequence is? What irrational numbers are? The structure and usefulness of Pascal's Triangle? The puzzling truth of the Klein bottle? Harmonic series? Countable infinite sets?

If you do, you will find this book entertaining for a couple of hours. If you don't, I believe you will find it mind - opening and liberating for five or six hours - and perhaps a lifetime. And, if all else fails, you will at least clearly understand what those mysterious terms and concepts mean, even though not one of them is named in the body of the book (because "technical terms don't exist in dreams"). They finally are identified in an appendix.

Up to enlightenment

If you have not the slightest interest in the concepts and forget them immediately after closing the book, I believe you will find ` as I did - that because of it you feel stimulated. And enlightened.

How does this book work? Is there an example of revealing an abstract complexity in all its naked simplicity? A power of the book is that doing so is virtually impossible, since each of the 12 chapters builds upon each that comes before it.

Suffice it to reflect that all numbers are made out of ones, and that zero - the "most sophisticated" number of them all - was the last number to be discovered (in China 2,000 or so years ago but unknown to the Romans). Onward and upward.

Do we need to know any of this? In real life, in truth, no, unless you know it all already. But, then, what is life for? Pick your own answer, but if it doesn't include something along the lines of exploration, expansion, discoveries of delight, I feel profoundly sorry for you.

The book is not, finally, as nourishing or as delightfully challenging as "Sophie." That is not a failing of its artfulness. It is just that an exploration of philosophy is more fascinating, more encompassing, than a tour of mathematics. "Sophie" focuses on the meaning of human existence, rather than abstract issues of logic.

For all its complexity, the pursuits of mathematics are clean and pure. The quests of philosophy are messy, troubling - and thus definingly human.

But in both cases, there is a strong reminder of the capacity for bliss to be found between any pair of human ears. The mind isn't ` or need not be - marshmallow. Try exercise. It works.

Pub Date: 10/11/98