Up until the 18th century, it was generally believed that Earth was only 6000 years old; it was only when James Hutton introduced his ideas that this belief was completely shattered. Hutton was a Scottish scientist born in 1726; he was educated in the local grammar school and then joined the University of Edinburgh. His interests were diverse; he enjoyed chemistry, entered a legal profession, and earned a degree in medicine.
He also examined the manufacture of sal ammoniac, and later became interested in farming; eventually, he was making a lot of money from his farm and from the manufacture of sal ammoniac. His business provided him enough money to pursue his interest, which he is most known for today: Geology.
At that time, Neptunists—a group of scientists named after Neptune, the Roman god of the sea—believed that in the past Earth was covered by an Ocean. They, also, believed that sediments formed the granite and crystalline rocks, and when seawater receded, “stratified” rocks appeared. Hutton, a leader of Plutonists—a group of scientists named after Pluto, the Roman god of the underworld—held totally different beliefs. According to Plutonists, the Earth is a dynamic body; it did not just come into being and then retained the same shape, but rather functions as a heat machine.
Hutton noted that subterranean heat, coming from under the surface of the Earth, led to the expansion of its outer parts; this eventually uplifted marine sediments and formed new continents. He noticed that granite is an intrusive igneous rock; he also noticed some unconformities in the rocks, which led him to believe that most rocks are not merely a product of sedimentation, but rather a product of sedimentation, uplift, and erosion.
This means that Earth undergoes a dynamic process and that it continually changes. In simpler words, rocks are eroded, the particles are buried deep in the sea, and the heat binds those particles together. Eventually, the heat uplifts the fused rocks up to form new continents; the process is always repeated. This means that Earth is definitely older than 6000 years. Hutton’s theory of Earth, which was announced in 1785, is his most important contribution to geology, and because of this theory, he is named the “Father of Geology”.
His theory also paved the way for one of the major concepts of geology: uniformitarianism or gradualism. According to uniformitarianism, the Earth’s shape is the product of a gradual process that has been occurring for thousands of years. Hutton believed that the same processes, which take place in the present, have also taken place in the past; that is, Earth is always being reshaped. Unlike gradualism, catastrophism states that Earth was affected by violent events, or catastrophes, which played an important role in shaping Earth. Hutton’s significance lies in his introduction to a concept that plays a great role in understanding Earth’s history.
Hutton is an important figure, because up until he came up with his theory about Earth, the world had not benefited from the wealth of knowledge present at the time. There was already a lot of information about rocks and fossils; yet, the belief that Earth was only 6000 years old was a stumbling block, because it left many questions unanswered. In a sense, Hutton’s theory collected the pieces of the puzzle and made sense of all the information available about Earth at that time. Hutton’s work more or less rocked the Earth; he questioned many of the prevailing ideas about Earth and its history.
For the first time, people realized that Earth was older than previously imagined; Hutton’s ideas helped put previous information into perspective. It is important to mention that Hutton’s work and ideas would not have had enough popularity without the effort of his close friend, John Playfair. Hutton’s style was difficult to understand, but Playfair rewrote his theories and ideas in an easy to understand way, while adding his own notes and observations in his publication entitled Illustrations of the Huttonian Theory of the Earth. Geology owes a lot to Hutton’s theories and also to Playfair’s help in making the work of this great scientist approachable.
References
britannica.com
encyclopedia.com
famousscientists.org
publish.illinois.edu