One of the fundamental bases of modern historical linguistics is the uniformitarian principle. This principle states that knowledge of processes that operated in the past can be inferred by observing ongoing processes in the present. The notion of uniformitarianism can be credited to British scientists, beginning with the work of the Scottish geologist James Hutton, who lived from 1726 to 1797. This was extended in the thinking of another Scot, John Playfair (b. 1748). And it became widely known as a result of the work of yet another Scot, Charles Lyell, in his 1830 work, Principles of geology.