Popper, Karl (1902–1994)

Karl Popper was one of the greatest political philosophers and philosophers of science of the mid-20th century. Born in Vienna in 1902,he was educated there and allied himself with the political left. Intellectually, he positioned himself in opposition to the “Vienna Circle,” who advocated logical positivism. During the triumph of fascism in the late 1930s, Popper left Europe for New Zealand, and then in 1946 immigrated to England, where he spend the rest of his life, teaching for 23 years at the London School of Economics, ultimately as Professor of Logic and Scientific Method.

Popper's vision of science, published initially in Logik der Forschung in Vienna in 1934, and as The Logic of Scientific Discovery in 1959,stressed “conjecture and refutation,” to borrow the title of a later book of his. Popper did not believe that ideas in science developed [Page 1900]by inferring from facts to more general understanding. Rather he believed that scientists drew on their insights to make a conjecture, a hypothesis. The next step was not to find all supporting evidence, but to seek any evidence that went counter to the hypothesis, and which, if found, would refute it.

For Popper, the most essential feature of a scientific theory was its refutability. That is, for a theory to be scientific, it has to specify that under certain conditions some things would happen, and—this is the crucial point—other things would not happen. In other words, a scientific theory had to forbid certain results. This quality allows scientific theories to be tested, and supported or refuted by the findings. Popper believed that a theory could never be proven; only its supporting evidence could be increased. However, a theory could be refuted decisively with contradictory evidence.

Here is a simplistic anthropological example: Let us assume that after studying a number of hunting peoples, we hypothesize that “all hunters and gatherers are nomadic.” Once we have defined “hunters and gatherers” and “nomadic,” so that we are clear about what we are talking about, each new case of hunting peoples that we encounter is a test of the hypothesis. Many such peoples are nomadic, and thus support the hypothesis. But once we discover the peoples of the Northwest Coast of North America, peoples who lived by hunting and gathering but who lived in permanent villages and could in no way be considered nomadic, we must conclude that our hypothesis has been refuted and must be considered incorrect.

Popper believed that several of the most popular theories of his day,Marxism and Freudianism, were unscientific, because they were used to explain everything and forbade nothing. That is, whatever happened could somehow be explained: for example, in Marxism, if the working class rebelled, it was seeking to protect its interests; if it did not rebel, it had a “false consciousness.” In Freudianism, an overprotected child was expected to be timid; a bold overprotected child was the result of a “reaction formation” and expected. Thus, theories that purport to explain everything really explain nothing; they are little more than totalistic ideologies.

Popper's political philosophy followed seamlessly from his philosophy of science. He was in favor of open debate and democracy, and opposed both fascism and communism as closed, totalitarian systems that violently suppressed legitimate disagreement. Popper's main work in this vein, The Open Society and Its Enemies (1945), offered a major critique of both Plato and Marx. Popper opposed closed societies because they were not susceptible to evidence, and he opposed revolution and radical change, because they were based on general models and did not allow correction of the many complex unintended consequences of change.

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