We take as a given that people are born in culture. They are raised in households in which they absorb manners, customs, and morals. We debate the role of nature vs. nurture but we don’t seriously doubt the determinative effects of nurture and indeed argue about the extent to which different environmental variables shape a human self: parenting, neighborhoods, education, religion. In an earlier era, another preoccupation shaped ideas about human nature that appears alien to us today: Had the earth’s climates & the configuration of its continents influenced a culture’s morality? What were the dangers of migration? Was the influence of new environments reversible?