Conservatism cherishes tradition; innovation fetishizes novelty. They tug in different directions, the one toward the past, the other toward the future.

Republicans were more pro-choice than Democrats up until the late 1980s.

History is the art of making an argument about the past by telling a story accountable to evidence. In the writing of history, a story without an argument fades into antiquarianism; an argument without a story risks pedantry. Writing history requires empathy, inquiry, and debate. It requires forswearing condescension, cant, and nostalgia. The past isn’t quaint. Much of it, in fact, is bleak.

Germ theory, which secularized infectious disease, had a side effect: it sacralized epidemiology.

Epidemics follow patterns because diseases follow patterns. Viruses spread; they reproduce; they die.

Stages of life are artifacts. Adolescence is a useful contrivance, midlife is a moving target, senior citizens are an interest group, and tweenhood is just plain made up.

History is hereditary only in this way: we, all of us, inherit everything, and then we choose what to cherish, what to disavow, and what to do next, which is why it's worth trying to know where things come from.