Beware of false fossils

In all the fuss about human cloning, has it occurred to you that identical twins are much more alike genetically than Dolly and her lamb, yet we never doubt that differences in nurture will shape them into different people?

Stephen Jay Gould is deeply puzzled that such an obvious point has been missing from the ethical debate; he seems to have been the first scientist to bring it up, at least in America. For this, in the usual rich agenda of provocations, Gould's global fan-club will prize his latest collection of essays.

This is the penultimate package of his monthly columns in the magazine, Natural History - he'll stop at number 300 as the real millennium dawns. He'll be missed for the tone of voice, as inimitable through his prose as Alistair Cooke's on radio - humane, amusing, deceptively casual - but also, of course, for his arresting range of erudition. (He is, for the record, Professor of Zoology, Professor of Geology, and Curator of Invertebrate Palaeontology, all at Harvard).

The new offering is, again, a whole shelf of topics in one volume, and almost any essay title would have done for it. The Lying Stones of Marrakech are modern and ludicrous fake fossils made in Morocco for tourists, but their uncanny similarity to fakes that fooled the 18th-century palaeontologist Johann Beringer is used to launch a telling parable on the misjudgments of hindsight.

The "intellectual synergy" between individual scientists and the big ideas in their lives continues to fascinate Gould, and his potted biographies are masterly and often moving. Those grouped to particular effect are the French thinkers who "invented the scientific study of natural history in an age of revolution" - driven men like Georges Buffon, who worked 14 hours a day for more than 40 years to produce 36 volumes of his monumental Histoire Naturelle.

Gould's particular hero - "the most stunningly incisive intellect I have ever encountered " - was Antoine Lavoisier, whose single geological paper, in 1789, fills the Harvard professor with "sheer awe accompanied by spinal shivers". The Frenchman theorised how changing sea levels would affect the composition of successive beds of sediment, and then proved it by fieldwork. He went on to deduce a long history for Earth and the role of fossil life in providing a narrative through time. Gould makes us share his admiration and enthusiasm for Lavoisier's logic and approach to proof: a great tutorial in the scientific method.

No collection of his would be complete without something to widen our reflections on evolutionary biology. This time it's the need to think at the proper scale and passage of time. Can we see evolution in progress? Gould takes some recent examples of adaptation among Trinidadian guppies and Bahamian lizards - studies that have excited the science correspondents. He invokes the echoing designs of Mandelbrot's fractal geometry to insist that these "rococo details" of short-term adaptation become "irrelevant and invisible jigglings in the majesty of geological time".

Michael Viney is an Irish Times columnist