Friday, November 26, 2010

When Theories Go Wrong

My hero, science writer Maggie Koerth-Baker over at Boing Boing, recently pointed to a scientists' list of favorite discarded theories: Larmarckian biology, the sun goes around the Earth, ulcers are caused by stress, that sort of thing.

Geocentric diagram of the solar system
As Maggie puts it,

Science can contradict itself. And that's OK. It's a fundamental part of how research works. But from what I've seen, it's also one of the hardest parts for the general public to understand. When an old theory dies, it's not because scientists have lied to us and can't be trusted. In fact, exactly the opposite. Those little deaths are casualties of the process of fumbling our way towards Truth.
The whole list of outmoded theories is worth reading, but here's my favorite, from medicinal chemist Derek Lowe:
The "bad air" theory of infectious disease. This is another one that you can find persisting for centuries. I'd say that it lasted for several factors: there were indeed such things as poisonous vapors which could make a person feel sick, for one thing. And the environments that were felt to have the worst vapors were often ones that had higher rates of disease due to the real factors (standing water, poor hygiene, overcrowded dwellings, and so on). Finally, there's the factor that's kept all sorts of erroneous beliefs alive — lack of a compelling alternative. The idea of strange-looking living creatures too small to see being the cause of infections wouldn't have gotten much of a hearing, not in the face of more tangible explanations.

That last point brings up another reason that error persists — the inability (or unwillingness) to realize that man is not the measure of all things. Unaided human perceptions on the human scale don't take you very far on the macro-scale of astronomy, or the micro-scale of cell biology (much less that of subatomic physics). To me, the story of science has been the story of augmenting our perceptions, and realizing that they had to be augmented in the first place. (Emphasis added.)
I also particularly enjoyed the contributions of Judith Harris (about two-thirds down the page), Alison Gopnick (near the bottom of the page) and George Lakoff (the very last entry).

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