Hutton’s empirical details have stood the test of time. It is now known that the greywacke layer which underlies much of the Scottish Southern Uplands is more than 400 million years old, and the sandstone is more than 300 million years old – ancient indeed! Hutton was also right about the Earth’s internal heat and its power to elevate. Only as recently as 1960 have geophysicists known that the Earth’s internal heat engine drives convection in the earth’s crust causing it to move and elevate. This is the basis of one of the most important discoveries of the last century – plate tectonics. Hutton’s supposition that igneous rocks had once been fluid was also correct.
His greatest contribution to science and philosophy, was his recognition of ‘deep time’, which was an essential forerunner to Darwinian evolution. His theory was popularised both by his biographer John Playfair and the nineteenth century geologist Sir Charles Lyell. Through Lyell, Hutton influenced Darwin (also a geologist), who in his Origin of Species wrote “It is hardly possible for me to recall to the reader who is not a practical geologist, the facts leading the mind feebly to comprehend the lapse of time…which the future historian will recognise as having produced a revolution in natural science” Both Lyell and Darwin owe this concept to Hutton. Hutton himself recognised natural selection, describing it as ‘a beautiful contrivance’.
His disciplined methodology has also been invaluable to the development of geology as a science; it is simply that any conjecture must be tested and refuted through verifiable predictions, with supportive accurate observations, and deductions guided by field evidence. Hutton was not the first to propose geological theories, but he was the first to make systematic use of refutation, enabling him to reliably prove his theory.
Hutton’s approach to geology and natural philosophy came from a very broad base of knowledge and experience of living systems as an innovative farmer and a medical doctor. He had a remarkably modern ‘holistic’ sense of our dynamic and habitable Earth “Here is a compound system of things, forming together one whole living world”. He claimed that sedimentary rocks are evidence of ‘a succession of worlds’, believing that this system was designed to maintain our ‘habitable earth’.
Hutton’s thinking was apparently influenced by his belief in deism ie the habitable Earth as a connected system. However, we now know particularly through the science of ecology, that we do indeed live in an interconnected and interdependent world. This is not just in terms of the habitable surface of the earth, but all of the earth as a planet and the planet as small part of our universe.