Category Archive: Hen’s Teeth and Horse’s Toes

W. W. Norton: 1984.

Gould’s view of Popperian falsification

Philosopher Karl Popper has argued for decades that the primary criterion of science is the falsifiability of its theories. We can never prove absolutely, but we can falsify. A set of ideas that cannot, in principle, be falsified is not science.

The entire creationist argument involves little more than a rhetorical attempt to falsify evolution by presenting supposed contradictions among its supporters. Their brand of creationism, they claim, is “scientific” because it follows the Popperian model in trying to demolish evolution. Yet Popper’s argument must apply in both directions. One does not become a scientist by the simple act of trying to falsify another scientific system; one has to present an alternative system that also meets Popper’s criterion—it too must be falsifiable in principle. [256]

Gould on fact and theory

Well, evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of in­creasing certainty. Facts are the world’s data. Theories are structures of ideas that explain and interpret facts. Facts do not go away when scientists debate rival theories to explain them. Einstein’s theory of gravitation replaced Newton’s, but apples did not suspend themselves in mid-air, pending the outcome. And humans evolved from apelike ancestors whether they did so by Darwin’s proposed mechanism or by some other, yet to be discovered.

Moreover, “fact” does not mean “absolute certainty.” The final proofs of logic and mathematics flow deductively from stated premises and achieve certainty only because they are not about the empirical world. Evolutionists make no claim for perpetual truth, though creationists often do (and then attack us for a style of argument that they themselves favor). In science, “fact” can only mean “confirmed to such a degree that it would be perverse to withhold provisional assent.” I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms. [254-5]