These remarkable fossils, one of the world's most important collections, appear to represent life in the seas soon after the period, some 570 million years ago, in which virtually all major groups of modern multicellular forms made their appearance. This collection is also special in that it preserves in great detail the soft anatomy of organisms. Walcott, studying these fossils, produced evidence for the existence of primitive ancestral types of later, improved forms. This interpretation remained inviolate until, in the 1960s, a trio of British paleontologists, Henry Whittington and his graduate students Simon Conway Morris and Derek Briggs, re-examined the fossils and came to radically different views about them. This initial set gave rise to a more limited set, not by diversification, but by elimination or decimation.
Contingency thus enters the equation.
Gould argues that this interpretation has profound consequences for our views of life and history. No longer is it possible to think in terms of a rational progression in which current life forms stem inexorably from those gone before. Lottery and Lady Luck play crucial roles. Contingency, which historians, novelists and filmmakers have embraced with gusto, becomes scientifically acceptable. This complex, witty, erudite book can be read at many levels.