Overall, it seems now possible to draw a reasonably good explanation of why the human condition is a singularity, why the likes of it has occurred only once and took so long in coming. The reason is simply the extreme improbability of the preadaptations necessary for it to occur at all. Each of the evolutionary steps has been a full-blown adaptation in its own right. Each has required a particular sequence of one or more preadaptations that occurred previously. Homo sapiens is the only species of large mammal – thus large enough to evolve a human-sized brain – to have made every one of the required lucky turns in the evolutionary maze. (45)

Auteur: Edward O. Wilson