Continental displacement/drift theory is among the most significant paradigm changes in science. It transformed our understanding of the planet Earth; a static picture of fixed continents gave way to a model of dynamic tectonic plates that shape our landscape, from mountains to continents. At present, the movement of continents is supported by direct measurements and established with the highest confidence allowed by the scientific method. However, the scientific establishment persistently rejected continental displacement/drift theory for over half a century despite the compelling evidence that Alfred Wegener provided in support of the theory. Why? Why did geologists and geophysicists ignore the evidence supporting Wegener’s theory?
The reasons include (i) the dogmatic belief that the oceanic crust was too firm for the continents to “simply plough through”, (ii) that most geologists viewed Wegener as an outsider to their field, and (iii) that Wegener’s data and arguments were misunderstood. Perhaps having biases about what is possible (i.e., reason i) and about people (i.e., reason ii) is inevitable human folly. Yet, allowing these biases to be justified by misinterpreting and ignoring data (i.e., reason iii) seems less inevitable. Rather, allowing dogma to suppress reason is the very antithesis of the scientific method, the very weakness of the human mind that the scientific method attempts to avoid.
How and why were Wegener’s data and arguments misunderstood? One of Wegener’s arguments was that the coastlines of different continents match one another complementary. After continent separation, erosion sculpts coastlines and thus complicates the analysis of coastline complementarity. To mitigate these complications, Wegener used the 200m isobath, not the modern coastlines. Still, his contemporaries incorrectly claimed that Wegener used modern coastlines, ignoring that Wegener used the 200m isobath. At the same time, mainstream geologists condoned the grave problems of the alternative theory favored by the establishment; this alternative theory posited — without empirical support — the existence of flooded land–bridges across the continents as an alternative way of explaining observed fossil distributions.
This dark age of 20th century science ended with data and reason triumphing over dogma, similarly to other discoveries that triumphed over their rejections. That is very encouraging. We should also remember, however, that dogma held reason back for half a century. This did not happen in Mediaeval Europe. It happened in the age of “modern science” and the atomic bomb. It happened because of sloppy reasoning and twisting arguments in favour of the preferred conclusion, the dogma of the time. What could be more inimical to science ? What is the antidote ?
3 thoughts on “The dark age of 20th century science”
This segment of an interview with William Glen, Historian of Science, Editor-at-Large of the Stanford University Press discusses variable standards of appraisal of scientific evidence. William Glen points to self-serving judgments and memory in the context of rejecting the continental displacement/drift theory and other paradigm changes pioneered by outsiders.
It seems the famous examples of mistaken ideas prevailing despite evidence usually feature a lone researcher who suffers for years because he champions the right idea. To understand why this happens, maybe it’s helpful to consider a similar story but one without such a victim: from the late 60s to the early 90s, the yeast mitochondrial genome was believed to be circular, despite mounting evidence that it is linear, as described in more detail here:
“The curious history of yeast mitochondrial DNA”
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This is a good example to show that the resistance to change is usually because of adherence to the dogma, not because of hostility toward the scientist(s) suggesting a new model. I think that in most cases, respected insiders of the field would have an easier time overcoming dogmatic biases. However, such respected insiders are rarely among the most likely scientists to suggest a brave new model that deviates substantially from the established orthodoxy.