Categorization, anomalies and the discovery of nuclear fission

The characteristics of scientific revolutions and by the same token the question of which events in the history of science deserve the name of revolutionary are controversial themes in the philosophy of science. An issue of disagreement is the question of whether or not events in which only parts of a paradigm are overthrown can truly be called a revolution, or if this term is to be reserved for the developments in which a wholesale replacement of ideas takes place. In this paper Kuhn's latest attempt to state a principle for distinguishing revolutionary developments will be reviewed, and it will be argued that certain developments entailing only partial replacements of the paradigm can be called revolutionary. The discovery of fission will serve as case study to illustrate this idea.