> It's only by the grace of something ... It seems a very reliable fact of human nature, based on millennia of evidence. We started building 10,000 years ago a

> It's only by the grace of something ... It seems a very reliable fact of human nature, based on millennia of evidence. We started building 10,000 years ago and haven't stopped. Humans are social animals; our primate ancestors also are social, living in groups of dozens. It's not an accident or good luck.