Eight years after his death, Popper's influence still felt

Saturday, July 27, 2002

Sunday is the 100th anniversary of the birth of Sir Karl Popper. His students and disciples have marked the occasion with conferences in Vienna, where he was born, and in New Zealand, where he taught during World War II. He died in 1994.

More lasting evidence of his enormous influence, however, is how many people rely on habits of thought he pioneered without any idea who said them first.

I cherish information, and I save it in vast and disorganized profusion. But I always have one special pigeonhole for things I absolutely do not want to lose track of. It includes, for example, a page from a statistical handbook giving the percentages of individuals in a normal distribution who differ from the norm by a given number of standard deviations. A table showing how to adjust the consumer price index for inflation from 1950 to 1995. Daniel Patrick Moynihan's "Defining Deviancy Down." Charles Murray and Richard Herrnstein's analysis of declining SAT scores.

And, as to this column, Popper's article for The Economist, April 23, 1988, "The open society and its enemies revisited." The title refers back to his 1945 book of the same (unrevisited) name, a scathing refutation of Marxism and the folly of central economic planning.

In his article, Popper briefly defines the classical theory of democracy "that democracy is the rule of the people, and that the people have a right to rule." But asking "who should rule?" is, in Popper's not-so-humble opinion, the wrong question. His "more realistic theory" asks instead, "How is the state to be constituted so that bad rulers can be got rid of without bloodshed, without violence?" His answer: "the rule of law that postulates the bloodless dismissal of the government by a majority vote." No majority, however large, should be able to overturn that rule.

In so saying, he sets himself against more than two millennia of political thought going back to Plato, an independent stance that troubles him not at all.

The insight that the ultimate aim of politics is not to pursue perfect governments, but rather to avoid bad ones, is paralleled in his 1934 book on science, The Logic of Scientific Discovery. A theory is scientific, not in the extent to which it has been proved true -- because that is impossible in any case -- but insofar as it is open to falsification.

Peter Munz, a student of Popper's and now a professor emeritus of history from Victoria University of Wellington in New Zealand, said in The Chronicle of Higher Education that Popper put the principle this way: "No number of sightings of white swans can prove the theory that all swans are white. The sighting of just one black one may disprove it."

Competing scientific theories, that is, make different predictions about the results of experiment or observation. Scientists go out and experiment or observe, and some theories perish with the sighting of a black swan, while others survive, provisionally, because the only swans they spot are white.

For instance, Isaac Newton's theories were wrong, in that he foresaw neither relativity theory nor quantum mechanics, but they were scientific because they made testable predictions. Until the 20th century, the results of observations did not falsify Newton's predictions, but it was always possible that they would.

Popper's insight bears on a modern controversy, the claim that the principle of "intelligent design" should be taught in schools on equal terms with the theory of evolution. Intelligent design, at least in its present state, is not a scientific theory because it makes no predictions that could be falsified.

The basic claim is that some natural systems are so irreducibly complex that they could not have evolved without some kind of nonmaterial intervention.

It's a stretch to go from "we don't have a material explanation" to "no material explanation will ever be possible." Ever is a long time; after all, Newton's mechanics lasted more than 200 years. But in Popper's terms, where would the proponents of intelligent design go looking for black swans? Evolutionary mechanisms are sufficient for some natural systems, just not all of them. If everything in nature is a white swan of some feather, then the theory predicts nothing, it can neither be proved nor disproved and it therefore cannot be scientific.

That does not mean, however, that it should not be taught; it is a perfect opportunity for "teaching the conflicts," in critic Gerald Graff's term. Understanding why the theory of intelligent design is essentially different from the theory of evolution is more important to students than whether they believe in either.