Reviewing the term uniformitarianism in modern Earth sciences

Uniformitarianism is a classical term of the geological sciences, coined in 1832 by Whewell to indicate a specific part of Lyell's hypothesis. However, over the years uniformitarianism has been used with different meanings, finally becoming synonymous with the entire theoretical system proposed by Lyell in his Principles. The popularity of this term and its frequently kaleidoscopic usage in the literature may be due in large part to the apparent simplicity of the “principle” of uniformitarianism. This is often summarized by the classical adage “the present is the key to the past”, a reductionist motto that has been passed through many generations of Earth scientists. In the text that follows, the major revisions of the term by Gould, Mayr and Rudwick are discussed in detail. These revisions are used as solid epistemological basis for understanding the countless “shades of meaning” attributed to the term over time, and the main reasons that led to the overgrowth of a semantic chaos; one that poorly fits a modern scientific discipline.Apart from the “invariance of natural laws” in space and time (the basic assumptions made in all scientific disciplines), all remaining “principles” historically related to, or imbedded within uniformitarianism, have been definitively falsified. Even the “Uniformity of process”, which is essentially coincident with the term “actualism”, can be applied only to certain categories of products and processes (or to some particular stages in the evolution of our planet). In many cases, an extension of a current process to the past and vice versa is not warranted, in view of the crucial importance played by “configurational causes” during the evolution of our planet.On the whole the analysis carried out highlights a real need to reconsider and investigate the epistemological underpinning of the Earth sciences, with one main effort aimed at solid preparation of young geologists, beginning with the basic courses of university education.