Faith Versus Fact : Why Science and Religion Are Incompatible (9780698195516) by Jerry A. Coyne Page A

is prevented from knowing what material she’s testing (“double-blind studies,” in which neither researcher nor patient knows the identity of the treatment being given, are the gold standard for drug testing); and data sharing, which requires scientists to provide their raw data to anyone who asks, ensuring that those who want to can search for anomalies and run their own statistical tests.
    Parsimony
    Scientific theories invoke no more factors than necessary to adequately explain any phenomenon. This, like everything in the toolkit of science, is not an a priori
requirement of the scientific method, but simply a method developed over centuries of experience. In this case, ignoring things that seem irrelevant keeps us from distracting ourselves with false leads. If we can completely explain the presence of smallpox by infection with a virus, why even
consider
factors like whether the patient ate too much sugar, or, indeed, whether, as was once thought, he was being divinely punished for immorality?
    One unparsimonious method is invoking gods. Our experience that supernatural hypotheses have never advanced our understanding of the cosmos has, as we’ll see later, led to the idea of
philosophical naturalism:
the notion that supernatural entities not only fail to help us understand nature, but don’t seem to exist at all.
    Living with Uncertainty
    One of the most common statements we hear in science is “I don’t know.” Scientific papers, even those that report fairly solid findings, are hedged with statements like “this suggests that . . . ,” or “if this finding is correct . . . ,” or “this result should be verified by further experiments.” Granted, scientists are people, and we’d like to know all the answers, but in the end it’s our ignorance that moves science forward. It’s no shame to admit it, for without the unknown, there would be no science, nothing to spark our curiosity. But that attitude assumes that there are some answers we might
never
know.
    One of these is how life originated. We know it happened between 4.5 billion years ago, when the Earth was formed, and 3.5 billion years ago, when we already see the first bacterial fossils. And we’re virtually certain that all living creatures descended from one original life-form, for virtually all species share the same DNA code, something that would be a remarkable coincidence if the code arose several times independently. But because the first self-replicating organism was small and soft-bodied and thus could not fossilize (it was likely a molecule, perhaps one surrounded by a cell-like membrane), we don’t have a way of recovering it.
    Now, we may be able to create life in the laboratory under conditions thought to prevail on the early Earth—I predict we’ll do this within fifty years—but that tells us only that it
could
happen, not how it
did
happen. Like historians lacking data on crucial events (was there a real Homer who wrote the
Iliad
and the
Odyssey
?), students of historical sciences like cosmology and evolutionary biology are often forced to live with uncertainty. (The uncertainty is not about
everything,
however: we know when both the universe and life on Earth began; we’re just not sure how.) Living with uncertainty is hard for many people, and is one of the reasons why people prefer religious truths that are presented as absolute. But many scientists (I am one) sharethe feelings of Richard Feynman, who expressed his comfort with ignorance in an interview with the BBC:
    I can live with doubt , and uncertainty, and not knowing. I think it’s much more interesting to live not knowing than to have answers which might be wrong. I have approximate answers and possible beliefs and different degrees of certainty about different things. But I’m not absolutely sure of anything, and there are many things I don’t know anything about,