What concept is Karl Popper best known for promoting in scientific philosophy?

Karl Popper is best known for promoting the concept of falsification in scientific philosophy. Falsification is the idea that for a hypothesis to be considered scientific, it must be testable and refutable. This means that there should be a possible observation or experiment that could demonstrate the hypothesis to be false. Popper argued that science progresses not by confirming hypotheses through verification, but by rigorously testing them and attempting to refute them. When a hypothesis withstands attempts at falsification, it gains credibility, but it is never conclusively proven true—this is a fundamental departure from verificationist approaches that posit that confirmation of a hypothesis is sufficient to establish its validity.

The notion of falsification has had a profound impact on the philosophy of science, emphasizing the importance of critical testing and skepticism in scientific inquiry. By advocating that science is characterized by its openness to being challenged and potentially disproven, Popper redefined how scientific theories should be evaluated and understood.