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Uniformitarianism |
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Uniformitarianism was a theory put forward by James Hutton in 1785, to explain how the Earth\'s rocks, continents and mountains had been formed. Until then, most people had accepted the idea that they were created instantaneously, by God or the gods, at a fixed moment in time—one 17th-century Christian prelate, James Ussher, even identified the year as 4,004  BCE—or had explained geology in terms of catastrophes like Noah\'s flood. However, Hutton, believed that his approach was consistent with the existence of a divine designer, though one working over very much longer timescales than that envisaged by the book of Genesis. Given the slow rate of processes, such as erosion and deposition, let alone that of evolution, uniformitarianism implies a much longer timescale than anyone had previously contemplated: hence Hutton\'s dictum ‘no vestige of a beginning, no prospect of an end’.
Hutton argued that many natural processes are cyclical. For example, land is uplifted to form hills which are then eroded to produce particles, which are transported and redeposited as soil or sediment. Indeed, he recognized that continuous destruction was needed to produce the soil which forms the necessary basis for plants and animals. In the longer term, he recognized that marine sediments could be uplifted to form new mountains.
A dispute that for a time overshadowed that between Uniformitarians and Catastrophists concerned the origins of granite. Hutton argued that this had formed by solidification from molten rock, but recognized that some granites were geologically quite recent. He was opposed by the so-called Neptunists, led by Werner, who argued that all rocks, including granite, had formed by precipitation from the universal ocean. Although it is now clear that Hutton was right, the Neptunists were more widely influential for decades after his death.
Such controversies, however, hardly affected the widespread acceptance of Hutton\'s views at the time among scientists in general, and the feeling that rationality (as opposed to superstition) was at last entering discussions of the origin of the Earth. Uniformitarianism inspired research in other areas, and led to even more radical proposals such as Darwin\'s theory of evolution by natural selection. They caused an uproar, nonetheless, among fundamentalist Christians and began a standoff between science and some Christian sects which persists today.
One interesting 20th-century development in the field is the realization that the ‘normal processes’ described by Hutton include occasional catastrophic events, such as meteorite impacts and huge volcanic eruptions. Modern thinking, therefore, although it still dismisses the need for divine intervention, has moved back some of the way towards catastrophism. PS
Further reading James Hutton, The Theory of the Earth; , James Ussher, Annals of the Old and New Testament. |
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