Intelligence

Scot who found deep time

Scotsman.com News - Scotland - Scot who found deep time

JACK REPCHECK

SCOTLAND’s pantheon of great thinkers includes David Hume, Adam Smith, James Watt, and Walter Scott. However the arguable titan of this august club is less widely known.

James Hutton, the 18th century Scots geologist, revolutionised our theories about the Earth with his realisation that the planet was far older than anyone had believed before.

According to the late scientist Stephen Jay Gould, Hutton "burst the boundaries of time, thereby establishing geology’s most distinctive and transforming contribution to human thought - deep time."

The discovery and acceptance of the earth’s ancient age - now understood to be about 4.6 billion years - was momentous for two reasons. Prior to Hutton’s work, most Europeans believed that the earth was not even 6,000 years old, an age which was drawn from the biblical book of Genesis. Many Christians were confident that God, who had recently created the earth, would soon end it, 1,000 years after the anticipated Second Coming of Christ. Hutton’s discovery shattered the concept of a seven-millennium Earth and changed the worldview of the Judeo-Christian west.

The second reason that Hutton’s discovery was seminal is that it quickly changed the template for scientists whose work focused on the earth and its inhabitants. Fossils would soon be understood for what they were. Much more significantly, within two generations of Hutton’s death, Charles Darwin would use deep time as the starting point for his theory of evolution through natural selection, the most important component of which was time - lots and lots of time.

So, who was James Hutton, and what allowed him to become such a unique thinker?

Hutton was born in 1726, the only surviving son of one of Edinburgh’s leading merchants. As a student at Edinburgh University, Hutton had the fortune to be taught by Colin Maclaurin, a leading interpreter of Sir Isaac Newton’s works. Maclaurin imbued his young charges with the science of Newton, emphasising the revolutionary power of the first known natural law - gravity. Maclaurin also promoted Deism, the belief in a benevolent creator god who allows his creation to run without interference. Hutton took both ideas to heart. He was also introduced to chemistry, which became a life-long love.

After leaving Edinburgh University, Hutton went to study on the continent, and returned with a medical degree. But he never practised as a doctor and in 1754 must have surprised many when he became a Borders farmer, having inherited his father’s farm.

Hutton remained a farmer for 13 years, and during this time began to form his theory of the Earth and eventually deduced its profoundly old age. Hutton came to realise that land erosion and sedimentary rocks were two parts of the same equation, and took this a step further. Believing in the benevolent deity, he could not accept that the Earth would just erode away, something which was widely believed. So using his knowledge of Newton’s laws, he developed his own theory. Although it was already accepted that sedimentary rocks form under water, previous theories suggested that those visible on the surface were the remnant of the waters which receded after the Flood.

But Hutton suggested that the Earth behaves in a cyclical way, with the land of the present eroding away to settle as sediments on the ocean floor, and becoming rock over long periods. Then - and this was the first of his two stunningly insightful realisations - he believed that those underwater sedimentary rocks were somehow raised from the depths to become new land. Hutton did not know how this process, which geologists of today call "uplift", occurred - but he knew it must require an immense amount of time - more than the 6,000-year history with which his age credited the planet.

Hutton left his farm in 1767, at the age of 41, and returned to Edinburgh, just as it was becoming the centre of the Scottish Enlightenment. Hutton would become best friends with Adam Smith, who also used natural laws (supply and demand) to explain how economies worked. Hutton also became a close acquaintance of the pre-eminent chemist, Joseph Black.

It was by applying one of Black’s ideas that Hutton finally found the engine for the "uplift" of sedimentary rock - subterranean heat from super-hot magma underneath the earth’s surface.

At a time when scientists thought that the planet was cooling, and that volcanoes were only local phenomena, Hutton’s embrace of heat beneath the Earth’s surface was shockingly bold. But it proved to be the second of his brilliant and correct insights.

It was not until 1785 that Hutton presented his work to the recently formed Royal Society of Edinburgh, in his paper "Theory of the Earth, or an Investigation of the Laws Observable in the Composition, Dissolution and Restoration of Land upon the Globe". His lecture created a small sensation, and his brilliant discovery of "deep time" revolutionised thinking on the planet on which we live.

• The Man Who Found Time: James Hutton and the Discovery of the Earth’s Antiquity, by Jack Repcheck, is published by Simon & Schuster on Monday, priced £7.99.

July 1, 2004 at 09:04 PM in UK | Permalink | TrackBack (189) | Top of page | Blog Home