A proper theory of morality depends upon the separation of intentions from results. - Stephen Jay Gould

All interesting issues in natural history are questions of relative frequency, not single examples. Everything happens once amidst the richness of nature. But when an unanticipated phenomenon occurs again and again—finally turning into an expectation—then theories are overturned.

We inhabit a complex world. Some boundaries are sharp and permit clean and definite distinctions. But nature also includes continua that cannot be neatly parceled into two piles of unambiguous yeses and noes. Biologists have rejected, as fatally flawed in principle, all attempts by anti-abortionists to define an unambiguous “beginning of life,” because we know so well that the sequence from ovulation or spermatogenesis to birth is an unbreakable continuum—and surely no one will define masturbation as murder.

As a final footnote to life’s little joke, I remind readers that one other prominent (or at least parochially beloved) mammalian lineage has an equally long and extensive history of conventional depiction as a ladder of progress—yet also lives today as the single surviving species of a formerly more copious bush. Look in the mirror, and don’t be tempted to equate transient domination with either intrinsic superiority or prospects for extended survival.