The paper is in five parts. A discussion of the flaws in social science as seen from the viewpoint of medical science is followed by a consideration of what they hold in common--the shared institutions and ideal programme of Science. The major differences that still remain are then characterized in two further sections; the first concentrates on the issues raised by the human species' distinctive place in evolution, while the second discusses the problems and advantages created for social science by its necessary closeness to lay thought. We conclude with a summary of the difficulties involved in scientific progress in social science and some speculation concerning disciplinary re-alignment.