Abstract

At the 1960 International Congress of Logic, Methodology, and Philosophy of Science, and again in his books Conjectures and Refutations (1963) and Objective Knowledge (1972), Karl Popper proposed a formal definition of what it means for one scientific theory to be “closer to the truth” than another (see popper). Such a concept was a necessary ingredient in Popper's philosophy of science, in which all our scientific theories are not only false, but bound to be false. We can never, according to Popper, arrive at the truth: a complete and adequate description of reality. (That such a reality exists, outside us, is the basic tenet of scientific realism.) Nonetheless, Popper holds, scientists do make progress ‐ namely, when they replace one false theory by another which, though still false, is closer to the truth, or, as we shall say, has greater verisimilitude.