In his lectures at the London School of Economics, Karl Popper said he hoped that we students would try out his philosophy in the various fields into which we moved. The career opportunities available to me in 1950 took me into the area of overlap between social anthropology and sociology. Several years of research and teaching passed, during which time I saw little opportunity to draw on Popper's advice until, in 1957, I met Joseph Agassi. The subsequent story has, necessarily, to be autobiographical, but it might have a wider import.