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When Crick and Watson began, they knew very little about DNA for sure, and part of what they were most sure of was wrong. To consider DNA as a physical object, they wanted diameters, lengths, linkages and rotations, screw pitch, density, water content, bonds, and bonds and again bonds. The sport would be to see how little data they could make do with and still get it right: the less scaffolding visible, the more elegant and astonishing the structure. More than sport was involved. Crick, following Pauling, elevated this penurious elegance into a theoretical principle, the corollary of model-building. “You must remember, we were trying to solve it with the fewest possible assumptions,” Crick said. “There’s a perfectly sound reason—it isn’t just a matter of aesthetics or because we thought it was a nice game—why you should use the minimum of experimental data. The fact is, you remember, that we knew that Bragg and Kendrew and Perutz had been misled by the experimental data. And therefore every bit of experimental evidence we had got at any one time we were prepared to throw away, because we said it may be misleading just the way that 5.1 reflection in alpha keratin was misleading.” We were in his office in Cambridge; thinking out loud, he got up and began to pace back and forth, with long, loping steps, in the clear lane in front of his desk, speaking in the rhythm of his stride. “They missed the alpha helix because of that reflection! You see. And the fact that they didn’t put the peptide bond in right. The point is that evidence can be unreliable, and therefore you should use as little of it as you can. And when we confront problems today, we’re in exactly the same situation. We have three or four bits of data, we don’t know which one is reliable, so we say, now, if we discard that one and assume it’s wrong—even though we have no evidence that it’s wrong—then we can look at the rest of the data and see if we can make sense of that. And that’s what we do all the time. I mean, people don’t realize that not only can data be wrong in science, it can be misleading. There isn’t such a thing as a hard fact when you’re trying to discover something. It’s only afterwards that the facts become hard.
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Horace Freeland Judson (The Eighth Day of Creation: Makers of the Revolution in Biology)