"Given that human societies, before they migrated out of Africa, in significant numbers were as close to sustainable as we’re likely to get, that is the best we can hope for, at least for future generations. But let’s not pretend that there is some sustainable way of life for future humans (our species) that we could hope they would attain. We’ve done that experiment. Humans didn’t live in harmony with nature. They got close, but ultimately couldn’t restrain themselves from causing some extinctions and then many more extinctions when they followed their migratory traits."