Exchange is to cultural evolution as sex is to biological...

If culture consisted simply of learning habits from others, it would soon stagnate. For culture to turn cumulative, ideas needed to meet and mate. The ‘cross-fertilisation of ideas’ is a cliché, but one with unintentional fecundity. ‘To create is to recombine’ said the molecular biologist François Jacob. Imagine if the man who invented the railway and the man who invented the locomotive could never meet or speak to each other, even through third parties. Paper and the printing press...