This paper concerns Jean Piaget's (1896–1980) philosophy of science and, in particular, the picture of scientific development suggested by his theory of genetic epistemology. The aims of the paper are threefold: (1) to examine genetic epistemology as a theory concerning the growth of knowledge both in the individual and in science; (2) to explicate Piaget's view of ‘scientific progress’, which is grounded in his theory of equilibration; and (3) to juxtapose Piaget's notion of progress with Thomas Kuhn's (1922–1996). Issues of scientific continuity, scientific realism and scientific rationality are discussed. It is argued that Piaget's view highlights weaknesses in Kuhn's ‘discontinuous’ picture of scientific change
