(I wrote this piece in 1997, but much of its content still holds, so here it is)
My friend Miguel Alcubierre is a researcher at the Max Planck Institut für Gravitantionsphysik, in Germany. Several years back he wrote a brief paper showing that, contrary to widespread belief, it is possible to travel faster than light without infringing the laws of relativity. The paper brought him some notoriety among physicists and sci-fi buffs, but particularly among scientific cranks. One of the chief aims of every self-respecting crank is to debunk the theory of relativity (and, of course, evolution). Miguel gets e-mail from the crackpot fringe on a regular basis. He says he has no time for them, so I asked him to forward them to me.
Scientific cranks are not just any kind of crank. They are usually curious and hard-working, sometimes even bright, and without exception completely innocent of the methods of science. Many cranks, I believe, are the possessors of scientific minds gone stale for lack of rigorous training. They believe that all that rings true to them must actually be true, and they cling fiercely to their prejudices. They are absolutely confident that all that glitters must be gold. Cranks think hard and come up with ideas, like scientists; but unlike true scientists they have an unrelenting faith in common sense.
Unfortunately for them, common sense --that invaluable aid in everyday life-- has proven a very poor guide for scientific discovery. As early as the sixth century BC, the Greek philosopher Parmenides attacked common sense, calling it “that heart devoid of the tremor of truth.” Syrian-born historian Ikram Antaki writes: “Common sense is the locus of our prejudices, where thought is reduced to its inertia (...) it provides ready-made answers; it inhibits and conditions our reflexes; it fabricates and channels our reactions (...) (common sense) is like the minimum wage of intelligence.” The investigation of the natural world has produced countless results that challenge common sense. Who would have thought, before Einstein, that an object’s mass increased as it moved faster? Or that it is possible to slow down time by moving at great speed? Still, these strange ideas are true in the sense that every experiment to test them has yielded positive results.
Why is common sense so unreliable in science? Common sense was a faithful guide to our forebears for thousands of years. We evolved it as a response to the world as perceived by our senses. But our senses are limited. Our eyes, for example, are sensitive to only a tiny portion of the electromagnetic spectrum. There are many more kinds of light than we perceive. The same applies to our hearing. We detect sound only in a limited range of frequencies. We should expect, then, that common sense is valid only in the realm of everyday experience. Scientific inquiry, however, routinely takes its partisans far from everyday experience. The physics of atoms seems very unnatural, but that is because our idea of what’s natural was forged among objects trillions of times larger than individual atoms. And the physics of objects moving at close to the speed of light is extremely weird, but then again, we don’t usually encounter such speeds on the Periferico.
Miguel’s cranks write with disarming confidence. In a way, I envy them. Their zeal and even their venom come from the certainty of being right. I wish I could be that certain of being right just once. But I guess I’m too far gone down a path where simple certainties dissolve. Don’t pity me, however. My simple certainties have dissolved into endless wonderment, and I think I know which one is best.