The incompatibility of Popper's philosophy of science with genetics and molecular biology
Sir,
The late Karl Popper is widely regarded as the most important of all philosophers of science. In 1972 Peter Medawar said ''I think Popper is incomparably the greatest philosopher of science that has ever been.'' Other leading scientists, such as Jacques Monod, John Eccles, and Herman Bondi, have expressed similar views. One of Popper's main conclusions is that everything achieved by science is, in principle, falsifiable. This had lead to a common view that nothing in science is certain, as there is always the possibility that a scientific law or conclusion will be proved wrong. A widely cited example of this is Newton's description of the universe, which held sway for over 300 years, until this century. Even Herman Bondi has been reported to have said of Newtonian theory: ''We may certainly speak of disproof now'' (cited in Ref. 1).
Such an extreme view can be attributed to Popper's philosophy of science, as expounded in The Logic of Scientific Discovery (published in German as Logik der Forschung in 1935, and in English in 1959. For a lucid summary, see Ref. 3). His starting point is David Hume's criticism of the inductive method of observation and conclusion. A common example, and used by Popper himself, is that no matter how many white swans are observed, we cannot conclude that all swans are white. The observation of a single black swan disproves the conclusion. This has come to be known as ''the problem of induction,'' and it has been of constant concern to philosophers that science, which is eminently successful, might be based on a method or on reasoning which is not logical. Popper claimed to have solved the problem of induction. Indeed, he said that induction is irrelevant to the pursuit of science; it does not exist; it is a myth.
In essence, Popper concludes that no scientific hypothesis, theory, or law can be fully verified, but it can always be refuted. Science proceeds by attempts to refute a hypothesis, and every time such an attempt fails, the hypothesis is strengthened. Observations and experiment lead to the modification and refinement of hypotheses or theories, but never to final proof. The principle of falsification always remains.
Most philosophers of science, including Popper, take their examples from physics. There is no discussion of chemistry