The general question which I wish to raise is this: What sort of social arrangements best facilitate the growth of scientific knowledge? What I am looking for is a normative sociology of science, one that is based on a good philosophical analysis of the aims and methods of science. I call the approach I am taking "Popperian" partly because this term immediately connotes an emphasis on open, critical debate and also because my ideas about both science and society have been influenced by Popper's work.