What is uniformitarianism in geology?

Uniformitarianism is the foundational assumption that the natural laws and processes operating in the universe today have always operated in the past and apply everywhere. In geology, it historically embodied the concept that the present is the key to the past, suggesting that geological events happen at constant rates. Today, while physical laws are viewed as invariant, Earth's history is understood as a slow process punctuated by occasional catastrophes.

What we know

• Uniformitarianism is the assumption that present-day natural laws and processes have always operated in the past and everywhere in the universe. [1, 2]
• In geology, uniformitarianism includes the gradualistic concept that the present is the key to the past and that geological events occur at constant rates. [2]
• The term was coined by William Whewell and proposed in contrast to catastrophism starting with James Hutton's late 18th-century work. [2]
• Modern geologists generally no longer hold to a strict gradualism, considering Earth's history to be a slow process punctuated by occasional natural catastrophic events. [2]

Still open

• Whether uniformitarianism is an unprovable postulate that cannot be verified using the scientific method, or a required first principle in scientific research.

Where to go next

• whoWho was James Hutton?
• compared withHow does catastrophism differ from uniformitarianism?
• a case in pointHow is the geologic time scale divided?
• the bigger pictureWhat is the broader scope of geology as a science?
• how it workedHow do geologists determine absolute ages of rocks?
• an unexpected connectionHow does a philosophical assumption connect to physical rock records?An unprovable metaphysical postulate about the constancy of natural laws underpins how scientists interpret physical chronostratigraphic units and rock sequences to reconstruct Earth history.

Sources

• [1]uniformitarianism (Wikidata Q208650) · CC0 1.0
• [2]Uniformitarianism · CC BY-SA 4.0
• [3]Geologic time scale · CC BY-SA 4.0
• [4]Geology · CC BY-SA 4.0
• [5]Outline of geology · CC BY-SA 4.0