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By Root 387 0

real, like itty-bitty planets, but they are everywhere and nowhere in their orbits at the same time—identify their position and you cannot know their momentum; track their momentum and you have lost their position (this is the so-called uncertainty principle). And electrons don’t exactly go “around” the nucleus; they form a “shell” described by a wave equation. And sometimes the electrons jump from inner orbits to outer orbits—and vice versa—without passing in between. How can that be? It seems impossible, but it is true nonetheless. A century of experimental evidence has been accumulated, often by physicists who were hard-core skeptics, demonstrating beyond almost any doubt that quantum physics is real.

Evolution is another of those scientific truths with which a number of people still struggle. Leaving out the religious objections (which are irrelevant in a scientific discussion), the counterintuitive nature of evolution is caused by two problems: (1) our propensity to favor the experimental sciences (e.g., physics) over the historical sciences (e.g., archaeology) as reliable sources of truth claims, and (2) our intuitive grasp of time frames on the order of months, years, and decades of a human life, in contrast to the history of life that spans tens and hundreds of thousands of years, and even millions, tens of millions, and hundreds of millions of years. These time frames are so vast that they are literally inconceivable. So let’s consider a very conceivable problem: explaining the great diversity of “man’s best friend,” dogs. There are hundreds of breeds of dogs, ranging in size from Chihuahuas to Great Danes, and varying in behavior from poodles to pit bulls. Where did all this canine variation come from? In 2003 geneticists found out—comparing the DNA of dogs and wolves, they determined that every breed of dog from everywhere on Earth came from a single population of wolves living in China roughly fifteen thousand years ago. Imagine that—in that short span of time (very short on an evolutionary timescale, speeded up, of course, by human intervention through artificial selection) we have this almost unimaginable degree of variation in dogs. It doesn’t seem possible, but there it is.

The human evolution story is much the same. In the May 11, 2001, issue of the journal Science, in a report on the “African Origin of Modern Humans in East Asia,” a team of Chinese and American geneticists sampled 12,127 men from 163 Asian and Oceanic populations, tracking three genetic markers on the Y chromosome. What they discovered was that every one of their subjects carried a mutation at one of these three sites that can be traced back to a single African population some 35,000 to 89,000 years ago. The finding corroborates earlier mitochondrial DNA (mtDNA) studies, along with fossil evidence, that every one of us can trace our ancestry to Africa not so very long ago. Looking around at the incredible diversity of humans on the globe, this seems nearly impossible. But the evidence supports it, and when it does scientists change their minds. One of the chief proponents of the theory that human groups (so-called races) evolved independently in separate regions (after a much earlier exodus out of Africa), the University of California, Berkeley, anthropologist Vince Sarich, after examining the new data, confessed: “I have undergone a conversion—a sort of epiphany. There are no old Y chromosome lineages [in living humans]. There are no old mtDNA lineages. Period. It was a total replacement.” In other words, in a statement that takes great intellectual courage to make, Sarich admitted that he was wrong.

Although scientists should probably make such admissions more often than they do, as a profession we are more open to error admission than most others. Can you imagine the shocked response a leading Democratic politician would hear if he made a statement like the following? “After examining the evidence for the claim that more gun control laws will reduce gun violence, I have changed my position. I am now against gun control.” Or think