Today, we analyze racism. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Stephen Jay Gould revisits the old arguments for racism -- a subject we've tried to deal with on moral, not rational grounds, as if race equity couldn't stand up to logic. Well, that's a serious miscalculation. Gould deals with two common threads of argument, one based on genealogy, one on geography.

Genealogy dominated the arguments as 19th-century thinkers tried to keep white supremacy intact. One notion was that, after God created perfect Adam and Eve, all branches of the human species deteriorated. Some branches deteriorated more than others. The other idea was that Biblical creation produced only the white race. Other races were produced by separate and lesser creations.

That falls apart as we learn more about genetics. Races are far less well-defined than we'd thought. Racial identity is a pitifully small part of genetic makeup. The fact we're a single human species means we breed across lines of race --mixing genes and hopelessly blurring the flimsy identification of the races.

Those genealogical arguments have died only in recent times. Hitler, and even Henry Ford, were still using them a scant sixty years ago. Meanwhile, the geographic question has lasted just as long. Where was Eden located -- What was Adam's race?

Since the Biblical accounts were written by tribes of the Eastern Mediterranean, that's where 19th-century scholars thought the human species arose. When the first australopithecine skull turned up in South Africa, in 1924, scientists, who'd been looking for human origins in Asia, rejected the find.

But Asia provided nothing old enough to be first, and Africa kept yielding very old human remains. Science finally had to concede the human species arose in Africa. Still, as late as 1962, a noted anthropologist wrote, "If Africa was the cradle of mankind, it was only an indifferent kindergarten. Europe and Asia were our principal schools." He was voicing a last-ditch, thinly-veiled claim that it was the northern races who learned to be fully human.

That notion has caved in very recently. New discoveries make it as clear as fine crystal that our first serious tool-making ancestors also arose in Africa. We left our African birthplace to spread across Asia, Europe, Australia, and the Americas, only after we'd learned the skills that made us human.

Gould ends his essay with a curious motto. "Human equality is a contingent fact of history," he says. "Say that five times before breakfast." Our equality is a contingent fact of history. By contingent, he means things might have worked out differently.

As it happens, our ape ancestors branched off and survived, while our later hominid ancestors died out. If those hominids had survived, then our species, in its many colors, would coexist with truly less developed hominids. It'd be a different ball game. But that's not how it worked out. We are one -- and only one --people.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

Gould, S.J., The Flamingo's Smile: Reflections in Natural History. New York: W.W. Norton & Co., 1985.