This year, physicists are celebrating the 100th anniversary of general relativity, Einstein’s theory of gravity. Although I’m an Einstein fan, I feel compelled to deplore one aspect of his legacy: the widespread belief that science and common sense are incompatible. In the pre-Einstein era, T.H. Huxley, a.k.a “Darwin’s bulldog,” could define science as “nothing but trained and organized common sense.”
Relativity and quantum mechanics, which Einstein also helped conceive, shattered common-sense notions about how the world works. The theories ask us to believe that an electron can exist in more than one place at the same time, and that space and time—the I-beams of reality—are not rigid but rubbery. Impossible! And yet these sense-defying propositions have withstood a century’s worth of painstaking experimental tests.
As a result, many scientists came to see common sense as an impediment to scientific progress. As biologist Lewis Wolpert once declared, “I would almost contend that if something fits in with common sense it almost certainly isn’t science.” Wolpert’s view is widely shared. When I invoke common sense to defend or—more often—criticize a theory, scientists invariably roll their eyes.
Scientists’ contempt for common sense has two unfortunate implications. One is that preposterousness, far from being a problem for a theory, is a measure of its profundity. The other, even more insidious implication is that only scientists are really qualified to judge the work of other scientists.
Needless to say, I reject that position, and not only because I’m a science journalist who majored in English. I have found common sense—ordinary, non-specialized knowledge and judgment—to be indispensable for judging scientists’ pronouncements, even, or especially, in the most esoteric fields.
For example, Einstein’s intellectual heirs have long been obsessed with finding a “unified” theory that accounts for all of nature’s forces. The leading candidate holds that reality stems from tiny strings, loops or membranes wriggling in a hyperspace consisting of 10, or 16 or more dimensions. String theory implies the existence of parallel universes—some perhaps mutant versions of our own, like “Bizarro world” in the old Superman comics—existing beyond the borders of our little cosmos.
These claims are preposterous, but that’s not my problem with them. My problem is that no conceivable experiment can confirm the claims, as most proponents reluctantly acknowledge. The strings (or membranes, or whatever) are too small to be discerned by any buildable instrument, and the parallel universes are too distant. Common sense thus persuades me that these avenues of speculation will turn out to be dead ends.
Ironically, while many scientists disparage common sense, artificial-intelligence researchers have discovered just how subtle and powerful an attribute it is. Over the past few decades, researchers have programmed computers to perform certain well-defined tasks extremely well. Computers can play championship chess, and juggle a million airline reservations, but they fail miserably at simulating the ordinary, experience-based intelligence that helps ordinary humans get through ordinary days. In other words, computers lack common sense, and that’s why even the smartest ones are so dumb.
Yes, common sense alone can lead us astray. Einstein himself once denigrated common sense as “the collection of prejudices acquired by age 18,” but he retained a few basic prejudices about how reality works. His remark that “God does not play dice with the universe” reflected his stubborn insistence that specific causes yield specific effects; he could never fully accept the bizarre implication of quantum mechanics that at small scales reality dissolves into a cloud of probabilities.
So far, Einstein seems to be wrong about God’s aversion to games of chance, but he was right not to abandon his common-sense intuitions about reality. In those many instances when the evidence is tentative, we should not be embarrassed to call on common sense for guidance.
John Horgan directs the Stevens Center for Science Writings. This column is adapted from one originally published in The New York Times.
