Realism and Anti-Realism in the Philosophy of Science

Throughout the 20th century, philosophers of science disagreed about whether science is a depiction of reality or simply an instrument for predicting the data of experience and obtaining power over nature. The first position may be called realism; the second, anti-realism. It turns out that this debate is not new but goes back to the beginnings of modern science and of modern philosophy of science. Newton and his followers were realists; the followers of Descartes were anti-realists. We shall study this difference by reading Newton, the Search After Truth of the Cartesian Nicolas Malebranche, and Hume’s melding of Cartesian with Newtonian positions in his Treatise on Human Nature. We shall then turn to 20th-century philosophy of science, particularly logical positivism, Karl Popper, and Thomas Kuhn. Popper can be seen as a realist, while the positivists were anti-realists. Both Popper and the positivists appeal to Hume’s arguments about induction to support their positions. We shall examine these opposing uses of Hume and try to arrive at a conclusion about the merits of each. Kuhn does not appeal to Hume, but his conception of “normal science” as a tradition resistant to novelties, which can be seen as lying between the realism of Popper and the anti-realism of the positivists, is strongly evocative of Hume’s understanding of causal belief as custom. Further, Kuhn’s description of science’s response to anomalies bears an interesting relation to Hume’s discussions of how we respond to violations of “the usual course of nature.” We shall see how his account of causal knowledge illuminates and is illuminated by Hume’s.