One of the most basic principles of modern
geology, the belief that the fundamentally the same geologically processes that operated in the distant past also operate today. Contrasted with catastrophism
?, which believes that earth surface features originated suddenly in the past, by radically different geological processes than those currently occuring. In the 18th and 19th centuries, uniformitarianism vs. catastrophism was very controversial, since uniformitarianism seemed to be incompatible with the prevailing religious beliefs of the time. Today, however, all mainstream scientists support uniformitarianism.