At the beginning of the 20th century, Alfred Wegener, a German scientist, was struck by the similarity of the coastlines of eastern South America and the West Coast of Africa. In 1915, he published his theory of the transposition of continents, which was based on the assumption that, sometime in the past, all the continents had been part of a single great landmass (Pangaea), which later broke up into separate landmasses which drifted apart, eventually forming the present continents. Wegener’s theory inevitably failed to give a scientific explanation of the mechanism behind continental drift. Nevertheless, it constituted a veritable revolution in geology. Yet it was indignantly rejected by the conservative geological community. The geologist Chester Longwell even went so far as to say that the fact that the continents fitted together so well was “a trick of the devil” to deceive us. For the next 60 years, the development of geology was hampered by the dominant theory of “isostacy”, a steady state theory that only accepted vertical movements of the continents. Even on the basis of this false hypothesis major steps forward were made, preparing the ground for the negation of the theory that increasingly entered into conflict with the observed results.

As so often happens in the history of science, technological advance linked to the requirements of production, provided the necessary stimulus for the development of ideas. The search for oil by big companies like Exxon led to major innovations for the investigation of the geology of the seabed, and the development of powerful new methods of seismic profiling, deep-sea drilling and improved methods for dating fossils. In the mid-1960s, Peter Vail, a scientist in Exxon’s main Houston laboratory, began to study the irregularities in the linear patterns on the ocean floor. Vail was sympathetic to the old French view of interrupted evolution, and believed that these breaks in the process represented major geological turning points. His observations revealed patterns of sedimentary change that seemed to be the same all over the world. This was powerful evidence in favour of a dialectical interpretation of the geological process.

Vail’s hypothesis was greeted with scepticism by colleagues. Jan van Hinte, another of Exxon’s scientists, recalled: “We palaeontologists didn’t believe a word he was saying. We were all brought up in the Anglo-Saxon tradition of gradual change, and this smelled of catastrophism.” However, Jan van Hinte’s own observations of the fossil and seismic record in the Mediterranean, revealed exactly the same as Vail’s, and the ages of the rock corresponded to Vail’s predictions. The picture that now emerges is clearly dialectical:

It is a common feature in nature: the drop that makes the bucket overflow. A system that is internally stabilised is gradually undermined by some external influence until it collapses. A small impetus then leads to dramatic change, and an entirely new situation is created. When the sea level is rising, the sediments build up gradually on the continental shelf. When the sea goes down, the sequence becomes destabilised. It hangs on for some time, and then – Wham! Part of it slides into the deep sea. Eventually, sea levels begin to rise and bit by bit, the sediment builds up.[4]

Quantity changed into quality when in the late 1960s, as a result of deep-sea drilling on the ocean floor, it was discovered that the seabed of the Atlantic Ocean was moving apart. The “Mid-Ocean Ridge” (that is, an under-sea mountain chain located in the Atlantic) indicated that the American continent is moving away from the Euro-Asian landmass. This was the starting-point for the development of a new theory, that of plate tectonics, which has revolutionised the science of geology.

Here we have a further example of the dialectical law of the negation of the negation, as applied to the history of science. Wegener’s original theory of continental drift is negated by the steady state theory of isostasy. This in turn is negated by plate tectonics, which marks a return to the older theory but on a qualitatively higher level. Wegener’s theory was a brilliant and basically correct hypothesis, but he was unable to explain the exact mechanism whereby continental drift occurs. Now, on the basis of all the discoveries and scientific achievements of the past half-century, we not only know that continental drift is a fact, but we can explain exactly how it takes place. The new theory is on a far higher level than its predecessor, with a deeper understanding of the complex mechanisms through which the planet evolves.

This represents the equivalent in geology of the Darwinian revolution in biology. Evolution applies not only to animate but also to inanimate matter. Indeed, the two interpenetrate and condition each other. Complex natural processes interconnect. Organic matter – life – arises inevitably from inorganic matter at a certain point. But the existence of organic matter in turn exercises a profound effect upon the physical environment. For example, the existence of plants producing oxygen had a decisive effect on the atmosphere and therefore on climatological conditions. The development of the planet and of life on earth provide a wealth of examples of the dialectics of nature, development through contradictions and leaps, long periods of slow “molecular” change alternate with catastrophic developments, from the collision of continents to the sudden extinction of whole species. Moreover, closer examination reveals that the sudden, apparently inexplicable leaps and catastrophes normally have their roots in the earlier periods of slow, gradual change.

  1. Ibid op. cit., p. 84.