Hutton, James (1726–1797)

James Hutton was a Scottish geologist, chemist, and naturalist noted for formulating the uniformitarianist doctrine and the Plutonist school of thought. After short careers in law and medicine at the University of Edinburgh, he followed his interest in chemistry and the nascent science of geology. He analyzed metamorphic and igneous rocks at Glen Tilt in the Cairngorm Mountains in the Scottish Highlands and layers of sedimentary rock at Siccar Point on the Berwickshire coast, east of Edinburgh. After these studies, he noted that the origins of sedimentary and igneous rocks are different and formulated theories on the earth's origin that paved the way for modern geological science. Hutton began a dispute with the popular Neptunist school, which suggested that all rocks developed by precipitating out of a single great flood. After studying the Devonian Old Red Sandstone along Scotland's coast, he realized sedimentary rocks originated not from a single flood but a series of successive floods. He established what became known as Hutton's Unconformity. Hutton reasoned that there must have been several cycles of depositing sedimentary layers, with each cycle involving deposition on the seabed, uplift and erosion, and new deposition on the seabed. He suggested that the stratigraphie record clearly indicated gradual géomorphologie processes throughout the earth's history.

Moreover, Hutton found granite penetrating metamorphic schists at Glen Tilt. This indicated that the granite had been molten in the past, suggesting that granite formed from the cooling of molten rock and not precipitation out of water. The suggestion that plutonic and volcanic activity were the sources of rocks on the surface of the earth replaced Abraham Werner's Neptunism theory, which claimed that rocks had originated from a great flood and were basically sedimentary in origin.

Hutton concluded that the history of Earth can be explained by observing the geological forces now at work. This is the basis of uniformitarian-ism, the doctrine that assumes that the natural processes of the past are the same as those that can be observed operating in the present: “the present is the key to the past.” The theory of uniformity is one of the most basic principles of modern geology. It contrasts with catastrophism, which states that Earth's surface features originated suddenly, through catastrophic geological processes (e.g., the biblical flood) that were radically different from current processes. Because of these hypotheses, Hutton was accused of atheism and poor logic, especially by Richard Kirwan, an Irish scientist who supported the catastrophist theory. Note, however, that many catastrophic events (e.g., earthquakes, glaciations, hurricanes, tsunamis, volcanic eruptions, meteoritic impacts, etc.) are perfectly compatible with uniformitarianism.

In 1795, Hutton summarized his views in a major work, The Theory of the Earth, where he affirmed: “Earth is very old and present-day geological structures formed slowly by processes observable today, such as erosion and deposition.” Hutton's theory was first presented at meetings of the Royal Society of Edinburgh in 1785, [Page 693]and published in Volume I of the Transactions of the Royal Society of Edinburgh, 1788. Two years before his death, Hutton published The Theory of the Earth in two volumes, consisting of the 1788 version of his theory with slight additions. In this work, Hutton compiled material on various subjects previously published, such as the origin of granite. His ideas influenced Charles Lyell's principles of geology, which in turn influenced Charles Darwin's theories of adaptive evolution.

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