The Uniformitarian-Catastrophist Debate

W lHEN, IN HIS Principles of Geology of 1830-1833, Charles Lyell revived and extended the geological ideas of William Hutton, he produced almost at once a division of English geologists into "Uniformitarians" and "Catastrophists," as that all-purpose Victorian thinker William Whewell dubbed the two opposing schools.' Lyell insisted on the explanation of geological phenomena by reference to secondary causes still observed to be in operation in the present, causes which have always been uniform in the same sense that they are uniform at present. By uniformity of "causes" Lyell meant not merely that the same geological agents (rain and rivers, earthquakes and volcanoes, etc.) have been at work in the past as in the present, but also that the quantity and intensity of the action of these agents have never varied. His view of the past was one of "endless variation"2 leading nowhere in particular, an apparently ceaseless repetition of continent-raising and continent-eroding processes. Moreover, in keeping with his belief that geology can never penetrate back beyond these repetitive cycles to an original or primitive state of the earth, he flatly denied that geology could show any over-all development of the surface of the earth in any particular direction from any knowable original state. He coupled to this assertion a full-length refutation of the theories of Humphry Davy and of Lamarck as to "the successive development of animal and vegetable life, and their progressive advancement to a more perfect state."3 Such a refutation was necessary to remove the possibility that paleontology could point back to a primitive lifeless condition of the earth, which would inevitably suggest radically different geological conditions, from which a developmental process could originate. The Catastrophists, led by the expert field geologist Adam Sedgwick and by William Whewell, attacked Lyell in two areas. First, they asserted the greater magnitude of geological forces in past time, especially at certain epochs where discontinuities between strata indicated vast powers at work-even, perhaps,