Karl Popper (1902-1994) shared many of the interests and commitments of Russell and the logical positivists but also differed from them in important ways. Much of the general understanding of the philosophy of science from WWII until the 1960s consisted in negotiating the differences between the logical positivists on the one hand and Popper and his followers on the other.
The selection from Popper in the KHR anthology dates from the early 1950s, the time when his views first became well known in England and America. He, along with Rudolph Carnap, Hans Reichenbach, and Carl Hempel (leading logical positivists), were the central figures in the philosophy of science until the 1960s, when attention turned to Kuhn’s work and its implications. You will find Kuhn and some other later figures referring to logical positivism and “falsificationism” (as Popper’s position came to be labeled) as alternative views, both of which they see as inadequate in some ways.
Popper gives you two good summaries (at the ends of sections I and III), so I’ll only note two points that don’t appear in them.
• Popper’s comment in the middle of p. 43 about the role of myth and metaphysics as the source of science is not a mere polite concession. Since Popper finds the heart of science in the testing of hypotheses, he places no constraints on their source, and he often insists that this source can lie in thinking that is not at all scientific.
• Think through the incompatibility Popper sees in the three statements (a)-(c) he discusses in section IV, and ask yourself which of the three statements you would give up.
The selections on the handout serve three purposes: (i) to provide a backup reading if you haven’t been able to get the KHR anthology in time for this class, (ii) to provide two useful ways of thinking about Popper’s views, and (iii) to fill out some ideas that don’t appear in the selection in that anthology.
• Two ways of thinking about the difference between inductivism and falsificationism:
• the contrast between instruction by the environment and selection by the environment,
• the images of the bucket and the searchlight.
(When presenting the image of the bucket, he refers to Francis Bacon, 1561-1626, whose Novum Organum, 1620, offered one of the first modern accounts of the methodology of science.)
• One added idea in these selections is the discussion of corroboration. Although this plays something like the role that confirmation plays for inductivists, notice that Popper insists that the better corroborated of two hypotheses need not be the more certain of the two.
• The second added idea is the focus of the selections from The Logic of Scientific Discovery (Popper’s main work, first published in 1934). Popper holds that, since the evidence that leads to the falsification of a hypothesis is itself falsifiable, we cannot count it as certain but instead must simply decide to accept it (and thus to reject the hypothesis).
(The “conventionalists” Popper mentions when discussing the last idea are a group of French thinkers from the early 20th century, most notably Henri Poincaré, 1854-1912, a very important mathematician with interests in physics, and Pierre Duhem, 1861-1916, a physicist who also wrote extensively about the history and philosophy of science.)