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

general theory of relativity was able to explain anomalies in the orbit of Mercury that could not be explained by classical Newtonian mechanics. A thick coat of hair, the lanugo, develops in a human fetus at about six months after fertilization but is usually shed before birth. That makes sense only under the theory of evolution: the hair is a vestige of our common ancestry with other primates, who develop the same hair at a similar stage but don’t shed it. (A coat of hair is simply not useful for a fetus floating in warm fluid.)
    Finally, it’s often said that the defining characteristic of science is that it is
quantitative:
it involves numbers, calculations, and measurements. But that too isn’t always true. There’s not a single equation in Darwin’s
On the Origin of Species,
and the whole theory of evolution, though sometimes
tested
quantitatively, can be stated explicitly without any numbers.
    As some philosophers have noted, the scientific method boils down to the notion that “anything goes” when you’re studying nature—with the proviso that “anything” is limited to combinations of reason, logic, and empirical observation. There are, however, some important features that distinguish science from pseudoscience, from religion, and from what are euphemistically called “other ways of knowing.”
    Falsifiability via Experiments or Observations
    Although philosophers of science argue about its importance, scientists by and large adhere to the criterion of “falsifiability” as an essential way of finding truth. What this means is that for theory or fact to be seen as correct, there must be ways of showing it to be wrong, and those ways must have been tried and have failed. I’ve mentioned how the theory of evolutionis in principle falsifiable: there are dozens of ways to show it wrong, but none have done so. When many attempts to disprove a theory fail, and that theory remains the best explanation for the patterns we see in nature (as is evolution), then we consider it true.
    A theory that cannot be shown to be wrong, while it may be
pondered
by scientists, cannot be accepted as scientific truth. When I was a child I made my first theory: that when I left my room, all my plush animals would get up and move around. But to account for the fact that I never actually saw them move or change their positions during my absence, I added a proviso: the animals would instantly assume their former positions when I tried to catch them. At the time, that was an unfalsifiable hypothesis (nanny cams didn’t exist). That seems silly, but is not too far removed from theories about paranormal phenomena, whose adherents claim—as they often do for ESP or other psychic “powers”—that the presence of observers actually eliminates the phenomenon. Likewise, claims of supernatural phenomena like the efficacy of prayer are rendered unfalsifiable by the assertion that “God will not be tested.” (Of course, if the tests had been successful, then testing God would have been fine!) A more scientific example of untestability is that of string theory, a branch of physics claiming that all fundamental particles can be represented as different oscillations on one-dimensional “strings,” and that the universe may have twenty-six dimensions instead of four. String theory is enormously promising because if it is right it could constitute the elusive “theory of everything” that unifies all known forces and particles. Alas, nobody has thought of a way of testing it. Absent such tests, it stands as a fruitful theory, but because it’s not at present falsifiable, it’s one that can’t be seen as true. In the end, a theory that can’t be shown to be wrong can never be shown to be right.
    Doubt and Criticality
    Any scientist worth her salt will, when getting an interesting result, ask several questions: Are there alternative