UNIFORMITARIANISM
 

Uniformitarianism is defined in the  Glossary of Geology, 2nd Edition  by Robert Bates and Julia Jackson (1980, American Geological Institute, pg. 677) as:

"...the fundamental principle or doctrine that geologic processes and natural laws now operating to modify the Earth's crust have acted in the same regular manner and with essentially the same intensity throughout geologic time, and that past geologic events can be explained by phenomena and forces observable today; the classical concept that 'the present is the key to the past'."
 

The doctrine of Uniformitarianism was significantly advanced by James Hutton (1726-1797) in his publication, Theory of the Earth (1785).  Hutton influenced Sir Charles Lyell (1797-1875), who is acclaimed as the father of modern geology with his three-volume work, Principles of Geology (1830-1833), which was responsible for the general acceptance of Uniformitarianism among geologists for the past 150 years.