Our dinner guest a few weeks ago got to talking about the thing we always get to talking about with dinner guests, The State of The Culture. He must have been drinking from the well of Evolutionary Psychology, because that is the angle he came at it from. There are (he claimed) tropical cultures and arctic cultures, with intermediate gradations. Human sexual bonding in pure-tropical cultures is of the “grazing” variety: a man hooks up with a woman, impregnates her, then wanders off and repeats the performance with another woman. The women don’t mind the looseness of their attachments, because in tropical circumstances food is easy to get, and a woman can raise children without much dependence on men. There are low levels of sexual jealousy, and “low-investment” parenting on the part of males. These males are, as the Evol-Psych jargon goes, “cads” rather than “dads.” In pure arctic cultures, by contrast, food can only be got by sustained arduous exertions. The species can only survive in an arctic climate by sticking doggedly together in tight kinship groups, practicing strict monogamy and high-investment parenting.

We in the modern West (our dinner guest argued on) are mostly people with arctic genes trying to adjust to a tropical culture. Not that our climate has changed in a tropical direction, but we have simulateda tropical climate by inventing equality of opportunity and the welfare state, in which environment—just as in pre-modern Micronesia or equatorial Africa—women don’t really need to have