The specific field of the history of science is the study and explanation of the origin and transformation of the structures of scientific knowledge. The historian of science should render understandable the reality of scientific research. The relationships between the history of science and the philosophy of science are examined stating that (1) the philosophical theories on the development of science have a scientific content only as much as they may be compared with the results of the history of science, (...) and (2) the philosophy of science does not refer to an immediate historical reality but to an intellectual reconstruction of the past. (shrink)