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Marek Kohn’s most excellent account of human evolution appears in paperback
this week. In As We Know It, he sorts out the flavours of evolutionary
theory to display what we know, and shows where the explanations break down and
contentious ideas step in. He describes, for example, Geoffrey Miller’s notion
that sex drives human evolution, forcing on us big brains and big vocabularies
as gaudy in their way as the bird of paradise’s feathers, and with roughly the
same function. He focuses on a single tool, the stone hand axe, to mark the
steps in the evolution of the mind.…