Background for Kuhn — remember that the key terms to associate with Kuhn and help you think about the development of science are: Normal science, paradigm, paradigm shift, and scientific revolution.

Karl Popper [1930s through 1950s]

Concentrating on logic of relation of theory to observation (data)

Popper’s Problem – Demarcate science from nonscience.   Can a given scientific theory be refuted?     That is, can it be falsified?   “Falsificationism” is opposite of “confirmationism,” which is belief that the truth of a theory increases with positive results, data that confirm an idea or theory. For Popper, the WORST thing that can said of some science is that it cannot be falsified. That is, it cannot be proved wrong. No matter what the data are, they can be interpreted to support the theory.  

Very compact outline of the basic logic:


Try hard to understand the example of the white swans. “All swans are white.”

In thinking about science, arguments around the ideas of Popper were most consuming when Kuhn came along. Kuhn changed the game and people then went back and forth about the relevance of Popper vis à vis Kuhn.

Students of Popper who brought enormous energy to the debates:   P. K. Feyerabend and Imre Lakatos.   Walt Weimer played in this ballpark with great gusto.

Popper is still influential in the sense that the ideals of refutation are logically stronger than confirmation. People do ask one another what, within their scientific activity is falsifiable, and take it to be a criticism of a theory if disconfirming data are ignored.

In the end, all of the main players accept the complexity of real science and know that it has no simple logic.

The threat of Kuhn’s ideas to many are that acceptance or rejection of something in science seems to be more of a matter of psychology (what persuades me?) than the logic of the relation of observation to theory.