The Pathological Disbelief of Alfred Wegener's Hypothesis of Continental Drift
The question from the USA was 'Is Continental Drift, as proposed by Alfred Wegener a fit example of Pathological Disbelief because he didn't fully explain the mechanism behind his idea. Was there any strong evidence for the solid earth theory that preceded continental drift? Did Alfred Wegener in fact suffer from Pathological Belief?
I spent some time trying to answer this question today and so of course, as a blogger, feel compelled to post my reply here too.
Continental Drift and Pathological Disbelief.
In my opinion the response of the scientific community to Wegener 's hypothesis of Continental Drift was an example of Pathological Disbelief.
Wegener had much evidence for his theory (or arguments as he called them) which disproved the accepted theory that the earth was solid, cooling down and shrinking (thereby wrinkling and causing mountain ranges and land bridges), and yet the establishment (as exemplified in the New York conference of Petroleum geologists in 1926) continued to believe in this despite a great catalogue complied by Wegener in his book The Origin of the Continents and Oceans' showing that the solid earth theory could not be true.
The solid earth theory was contradicted by gravity measurements which showed that continental rocks are less dense than oceanic rocks which led to the idea of isostacy - that the continental rocks floated in the mantle -which implies a certain amount of liquidity. Furthermore if the components of the earth's crust were in such a system of equilibrium this would not allow rocks to bob up and down from one geological epoch to another - which would preclude land bridges.
Another piece of evidence which supported Wegener's continental drift but did not support the idea of a cooling earth was radioactivity. This had recently been discovered and there was enough radioactive material being found in the earth for Wegener (and the rest of the scientific establishment, if they were not suffering from PD) to question the idea that earth was cooling down very much at all - certainly not as much as the accepted theory.
The earth could not be contracting and crinkling as much as required either. Measurements on the folding observed in mountain ranges would seem to suggest that the rocks crinkled to become many times shorter length (and therefore that the earth had contracted a similar number of times in volume). Wegener's idea that the uplift was caused by continents colliding and crumpling up oceanic sediment between them was supported by the marine fossils found high in the mountains. It would take someone with profound PD to argue otherwise.
Wegener could provide an explanation in terms of continental drift for everything that was produced by the people that disbelieved him at that conference in 1926 but he did not attend. He had invented a new way of thinking that explained all the existing evidence which included:
(i) matching fossils either side of the ocean;
(ii) matching rocks;
(iii) rocks that had obviously been formed in climates vastly different from the climates that they are in now;
(iv) worms and other simple animals that showed biological similarities though now thousands of miles apart and
(v) simple matching of the outline of the continental shelves.
He invoked the idea of rocks that had properties of solids and liquids and thus could flow and transmit earthquakes which was one of the main reasons why solid earth enthusiasts dismissed (or disbelieved) his idea.
The fact that he did not have a mechanism for his hypothesis he did not regard as a problem. He simply said that the Newton of Continental Drift has yet to appear - and equated himself with Copernicus. He had so much evidence for his idea (evidence that was inconsistent with the other prevailing theories of the time) that he could not see how anyone could disagree with an idea that so neatly explained everything that had been discovered and was being discovered around him. It was the best model for the time.
The evidence that came later (the magnetic stripes alongside the mid-oceanic ridges for example) support a new idea - that of plate tectonics which provides evidence for why the continents drift. It was only then, when there was a unified theory that explained a whole series of phenomena, that the idea that people began to believe that Wegener was right when he'd said the continents had drifted and the disbelief ended.