ABSTRACT
Several years ago Sir Peter Medawar urged analysts of science to study in detail "what scientists do" in the course of their research. As a distinguished practicing scientist, Medawar himself was well aware that what scientists say about their activity can never be taken at face value. Instead he urged that “only unstudied evidence will do — and that means listening at a keyhole”. The Devonian controversy arose in the course of development of ‘normal science’. The dominant cognitive enterprise within geology in the 1830s was an attempt to order the sequence of strata in the Earth's crust. The increasingly explicit goal of this collective effort was to reconstruct the history of the Earth and of life on Earth before the advent of human beings. In crude or ‘coarse-grained’ outline the Devonian controversy illustrates a dynamic pattern of theory construction that may be much more common than either philosophers or historians of science have generally recognized.
