AbstractA concise review of concepts dealing with the genesis of granite in the late 18th, 19th, and early 20th centuries is given. Arguments are provided for the repeated recurrence of genetic concepts in an altered form which were separated by periods in which a rival concept was dominant. This type of development may be likened to Eldredge and Gould's (1972) punctuations of biological equilibrium. On the other hand phases of development may be recognized in which rival concepts tend to converge towards a unified content, thus conforming to the ‘tree of knowledge’ hypothesis of Popper (1972). In this context the two metaphors do not appear to be mutually exclus