Summary of Karl Popper’s the Logic of Scientific Discovery
Language analysts believe that there are no genuine philosophical problems, or that the problems of philosophy, if any, are problems of linguistic usage, or of the meaning of words. I, however, believe that there is at least one philosophical problem in which all thinking men are interested. It is the problem of cosmology: the problem of understanding the world—including ourselves, and our knowledge, as part of the world.
The annexation of Austria in 1938 became the catalyst which prompted Popper to refocus his writings on social and political philosophy and he published The Open Society and Its Enemies, his critique of totalitarianism, in 1945. In 1946 he moved to England to teach at the London School of Economics, and became professor of logic and scientific method at the University of London in 1949. From this point on his reputation and stature as a philosopher of science and social thinker grew enormously, and he continued to write prolifically—a number of his works, particularly The Logic of Scientific Discovery (1959), are now widely seen as pioneering classics in the field. However, he combined a combative personality with a zeal for self-aggrandisement that did little to endear him to professional colleagues at a personal level. He was ill-at-ease in the philosophical milieu of post-war Britain which was, as he saw it, fixated with trivial linguistic concerns dictated by Wittgenstein, whom he considered to be his nemesis. Popper was a somewhat paradoxical man, whose theoretic commitment to the primacy of rational criticism was counterpointed by hostility towards anything that amounted to less than total acceptance of his own thought, and in Britain—as had been the case in Vienna—he became increasingly an isolated figure, though his ideas continued to inspire admiration. In later years Popper came under philosophical criticism for his prescriptive approach to science and his emphasis on the logic of falsification. This was superseded in the eyes of many by the socio-historical approach taken by Thomas Kuhn in The Structure of Scientific Revolutions (1962), who—in arguing for the incommensurability of rival scientific paradigms—reintroduced the idea that change in science is essentially dialectical and is dependent upon the establishment of consensus within communities of researchers.
Popper’s proposals concerning demarcation can be usefully seen as a response to the verifiability criterion of demarcation proposed by logical empiricists, such as Carnap and Schlick. According to this criterion, a statement is cognitively meaningful if and only if it is, in principle, possible to verify. This criterion is intended to, among other things, capture the idea that the claims of empirical science are meaningful in a way that the claims of traditional philosophical metaphysics are not. For example, this criterion entails that claims about the locations of mid-sized objects are meaningful, since one can, in principle, verify them by going to the appropriate location. By contrast, claims about the fundamental nature of causation are not meaningful. While Popper shares the belief that there is a qualitative difference between science and philosophical metaphysics, he rejects the verifiability criterion for several reasons. First, it counts existential statements (like “unicorns exist”) as scientific, even though there is no way of definitively showing that they are false. After all, the mere fact that one has failed to see a unicorn in a particular place does not establish that unicorns could not be observed in some other place (Schilpp, Paul Arthur, ed. 1974). Second, it inappropriately counts universal statements (like “all swans are white”) as meaningless simply because they can never be conclusively verified. These sorts of universal claims, though, are common within science, and certain observations (like the observation of a black swan) can clearly show them to be false. Finally, the verifiability criterion is by its own light not meaningful, since it cannot be verified. Partially in response to worries such as these, the logical empiricists’ later work abandons the verifiability criterion of meaning and instead emphasizes the importance of the empirical confirmation of scientific theories. Popper, however, argues that verification and confirmation played no role in formulating a satisfactory criterion of demarcation. Instead, Popper proposes that scientific theories are characterized by being bold in two related ways (Thornton, Stephen. 2014).
To sum up, Popper’s contributions to thought are of profound importance, but they are not the last word on the subject. They need to be improved. My concern in this book is to spell out what is of greatest importance in Popper’s work, what its failings are, how it needs to be improved to overcome these failings, and what implications emerge as a result.
Schilpp, Paul Arthur, ed. 1974. The Philosophy of Karl Popper. 2 volumes. La Salle, Ill: Open Court.
Thornton, Stephen. 2014. “Karl Popper.” In The Stanford Encyclopedia of Philosophy, edited by Edward N. Zalta.
Tichý, Pavel. 1974. “On Popper’s Definitions of Verisimilitude.” The British Journal for the Philosophy of Science 25 (2): 155–60.