Sunday, October 22, 2006

The Pathological Disbelief of Alfred Wegener's Hypothesis of Continental Drift

I just had a very interesting question sent to me from a university in the USA. In 2004 Professor Brian Josephson gave a lecture to a group of physics nobel laureates in Lindau. It was called Pathological Disbelief (you can see the slides for it here if you open the pdf file of the talk near the top). In the lecture, which sounds both entertaining and quite fascinating, Professor Josephson questions why certain ideas are rejected by the scientific community.

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.


Anonymous Anonymous said...

Very interesting, Clare. Then as now (as you showed in your very readable and highly recommended novel), it was difficult to get the scientific community to take a hypothesis seriously.

I think there are parallels between the story you tell and the case of Darwin and inheritability. Darwin did not quite get as far as the evidence for his observations, because he was unaware of Mendel's work, lying in an obscure Austrian monastery. He (Darwin) did allude to "gemules" but he never quite got as far as to conceptualise what we now call "genes" as a unit of inheritance.

however, I am sure that in many cases, scientists who have these hypotheses without evidence, grand or not, committed or not, are cranks who are not prepared to go the Occam's razor route of suggesting an experiment to distinguish their ideas from a host of others. My own ex-field, muscle contraction, is riddled with people who have grandiose hypotheses for how muscle works -- which go considerably less far tha the existing main theory and its associated evidence.
I will restrain myself from commenting on Brian Josephson as this is a public internet.

thanks again for sharing your thoughtful post.

Sun Oct 22, 09:38:00 pm  
Anonymous clare said...

Thanks Maxine. Yes, there are similarities with Darwin.

Strange that Darwin is so well known but Wegener is not. I often wonder why.

Mendel is another very interesting character, I think, and as obscure as Wegener, perhaps - in fact I was going to write about him and was just starting my research when my mother rang to tell me that a book called 'A monk and three peas' was being read out on the radio. I loved his story of working away in obscurity - it had some of the romance of Wegener's. Another feature I learnt about his story, quite recently was that several people unearthed his results at the same time at a later date -as if only then the world was ready for heredity.

And yes, there are many people with bizarre ideas - in fact some of them have written to me since I've written this book - and some of them wrote to Wegener too.

Sun Oct 22, 11:53:00 pm  
Anonymous marly said...

What bizarre ideas? That Pedro the miniature mummy was a Nimerigar? That a prehistoric map shows the moon's craters? Tell! (By the by, I did. Tell, that is.) It would make a lovely post.

Mon Oct 23, 03:53:00 pm  
Anonymous Maxine said...

I think one reason Darwin attracts attention is the R word-- religion. Becuase he (against his own retirning inclination) became embroiled in religious controversy, a whole other side to his work fed public interest and continues to do so today, with creationism and now intelligent design.
Although, as you so ably describe in your book, Wegener was a polymath, he and other great scientists like him do not gain the notoriety of those who have a "hook" for the media. Workable theory?

Mon Oct 23, 11:41:00 pm  
Anonymous clare said...

Marly: Funny you should mention the moon's craters...I did see some letter sent to Wegener by an indignant Englishwoman claiming her faher had thought of this continental drift thing first - and that it was all to do with saturn crashing into the moon and then careering off again...or something equally bizarre.

His grandson showed it to me. What struck me was the way that Wegener had kept this letter just as carefully as he kept everything else - showing it the same respect as the more useful letters.

Maxine: Yes, I'm sure that must be at least part if not all of the reason - that, and the way we seem to be most interested in things to do with ourselves. Forebears - be they primates or people - are much closer to us (and therefore more interesting) than rocks.

The religious issue is the reason why also I think Darwin would not have been a blogger. He would have been scared of betraying what he knew too soon.

And yes, you're right. He didn't seem to have a hook for the media. Although he argued gently about certain aspects when the ridicule started he simply went on quietly to different work.

Tue Oct 24, 12:23:00 am  
Blogger Jonathan said...

It is not easy to change ideas. The previous model of the earth as a shrinking and wrinklng (mountains) object goes back to Descartes model of the earth of 1664. I wrote about it here. According to the text book I was reading, the idea of continental drift did not really gain acceptance in America until the 1950s, and then it was the ocean floor data which caused the theory to be accepted, a dataset which Wegener didn't have.

You'll notice that the post is called: 'The Expanding Earth, Part 1". I've yet to write Part 2, the post that explains why some people think the earth is expanding. It's about time I did...

Tue Oct 24, 05:33:00 am  
Blogger Antony said...

There is an underlying explanation to pathological disbelief that led to the rejection of Wegener's ideas. It is based on the psychological theory that the primary mode of human thought is the metaphor, and that people are inclined to reject new ideas if they do not fit the metaphors they are comfortable with. George Lakoff, in his book "Metaphors We Live By" discusses those ideas. In this case the conflicting metaphors are those of a cooling ball versus items floating in a denser medium, both concepts that we commonly experience. The disbelief seems pathological becuase we cling to the old metaphors so tightly.

Wed Mar 07, 06:30:00 pm  
Blogger Joe Allen said...

could you give me some reasons why scientists at the time though the theory was wrong, it would be very helpful, i cannot find anything on the web and i need it for GCSE Science!
thank you:)

Sat Apr 20, 11:57:00 am  
Blogger Clare Dudman said...

Hi Joe, I suggest you read a few books- there's lots around on the topic. Maybe go to a library and ask a librarian to help you there.

Thu Apr 25, 09:39:00 am  

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