Some histories of science present a smooth succession of ideas and breakthroughs and unambiguously identify particular scientists responsible for each quantum advance. This picture is both naive and incorrect. Many principles were introduced into science only with difficulty and were originally opposed by the scientific establishment.
I will illustrate this by a couple of examples from the science of geology.
One of the most famous names in geology is Alfred Lothar Wegener (1880-1930), the German meteorologist and geophysicist. Wegener is known as the Father of Continental Drift, but in his day he was a lonely pioneer. In 1910, Wegener noticed that if the edges of Africa and South America were slid together they would fit like pieces in a jigsaw puzzle. He became obsessed with this idea and developed it to conclude that not only Africa and South America, but all the land masses of the world had originally been fused into one super-continent which he called Pangea (pan meaning all and Gea, the Greek goddess of Earth).
Wegener proposed that Pangea had broken apart and the pieces, the continents, are now drifting over the surface of the planet.
Of course Wegener based his theory on more evidence than the complementary shapes of the continents. He also noted, for example, that identical fossilised animal remains were found in west Africa and in east South America, even though the continents were separated by a wide ocean. This was readily explained if the two continents had once been united.
He published his ideas in 1915 in the book Origin of Continents and Oceans, but failed to convince his scientific colleagues. He died on an expedition to Greenland in 1930, his ideas unaccepted.
Although Wegener was the first to formulate a comprehensive theory of continental drift, parts of his ideas had occurred to many people over previous centuries. These include the English philosopher Sir Francis Bacon, the German naturalist Alexander von Humboldt and, shortly before Wegener, two Americans, Howard Baker and Frank Taylor, who proposed that the moon's tidal pull set the continents in motion.
In the 1950s and 1960s many geologists revived Wegener's ideas and produced a mass of evidence to convince the geological world that continental drift was a reality.
One problem which had stumped Wegener was to explain how continents could possibly move, anchored as they were in the rock of the ocean floor. This problem was solved by the Canadian geologist J. Tuzo Wilson, who proposed that the outer crust of the Earth is broken into large plates and that the continents passively move as passengers on the backs of these plates.
The plates themselves are floating on the Earth's mantle (the part between the crust and the core) which is partly molten and carries convection currents similar to convection currents that develop in a pot of water heated on a hot-plate. These convection currents move the great tectonic plates.
The idea of an earth with molten under layers and a broken crust with its pieces moving about on the currents of this under layer is not an exclusively 20th-century concept. As long ago as 1782, Benjamin Franklin suggested this idea in a letter to a friend.
Another famous name in geology is Jean Louis Rudolphe Agassiz (1807-1873), the Swiss-born geologist who developed the idea of the Ice Age.
He is reputed to have said: "Every great scientific truth goes though three stages. First, people say it conflicts with the Bible. Next they say it had been discovered before. Lastly they say they always believed it." This remark was probably triggered by the difficulties he encountered in having his proposals about the Ice Age accepted by his scientific colleagues.
In 1837 Agassiz read a paper at the Swiss Society of Natural Science in Neuchatel giving a new explanation of the phenomenon of erratic boulders. The native rocks near Neuchatel are limestone but contain many boulders of granite and schist that could only have come from mountains many miles away called the Bernese Oberlands.
These "erratic boulders" were a great curiosity and were explained by the great British geologist Charles Lyell to result from Noah's flood, which rolled them far from their native origin.
Agassiz was convinced, however, that the erratic boulders were explained by a great sheet of ice that once covered all of Switzerland. He declared that this layer of ice had reached from the North Pole to the Mediterranean and he coined the term Ice Age. He postulated that modern glaciers were tiny remains of this ancient ice sheet.
Agassiz explained the erratic boulders, and many other features of the local terrain, by the action of the ice sheet expanding across the continent sweeping rocks, sand and gravel along with it and, later, leaving the boulders behind when it receded northwards once again.
Many people did not take kindly to Agassiz's hypothesis. They felt he was challenging the authority of Scripture. Agassiz invited his audience of scientists to come with him to the slopes of the Jura, where he pointed out the erratic boulders and heaps of rubble lying along the trail of the glacier that had deposited them.
He identified the glacier trail by pointing to where the ice had scored, polished and scraped the limestone bedrock leaving stripes identical to those found on the margins of modern glaciers high in the Alps.
The geologists remained sceptical of Agassiz's ideas and it took many years of campaigning by him before Lyell and other leading figures were convinced. It is interesting that the peasants who lived in the region had always understood how the erratic boulders reached their improbable resting places. Before Agassiz's breakthrough the occasional scientist, impressed by peasants' explanations, had taken up the cause, but had always been ignored by their scientific colleagues.
(William Reville is a senior lecturer in Biochemistry and Director of Microscopy at UCC)