Some ideas are very attractive, and quickly capture people’s imagination.
One such idea is that there are mantle plumes deep in the Earth, up which superheated molten rock ascends, melting through the lithosphere at the surface of the Earth, and creating volcanoes. And as the plates of the lithosphere move over a fixed mantle plume in the Pacific ocean, the volcanic Hawaiian islands are formed in a chain leading away from the mantle plume.
This idea appeared in about 1970, shortly after the idea of plate tectonics took hold, and it seems it’s now taught in geology courses along with plate tectonics. It’s become part of the science of geology.
But it seems that some people think the idea is physically implausible, and in fact a complete myth:
There is not even any agreement about the existence, or location, of features under Hawaii, the poster child of the plume myth. The original, now largely abandoned, definition of ‘plumes’ involved self-driven, strongly buoyant, narrow upwellings from fixed points at great depth, which drove plate tectonics, kept ridges open and provided much of mantle heat-flow.
And a very long-running myth:
The plume debate is now one of the longest standing scientific controversies in the Earth sciences, having lasted longer than the age of the Earth, crustal growth and fixity-vs-drift controversies.
Some questions come to mind, that don’t seem to have been answered. If there’s a continuous plume of superheated molten rock flowing up the plume, why aren’t the volcanoes in the Hawaiian islands in continuous eruption, rather than intermittent eruption? And why isn’t there one long narrow island extending away from the mantle plume, rather than a series of islands? Is the plume intermittent? And is it really thermally plausible for there to be what is effectively a huge blowtorch burning its way through tens of kilometres of solid rock to the surface? Wouldn’t the mantle plume widen as it rose, just like the plume of smoke above a cigarette (left)?
Once the plume idea took hold, the plumes began to multiply in numbers, and behave in all sorts of ways.
A simple, elegant, satisfyingly neat, concise, falsifiable hypothesis has become a complicated, awkward, messy, unfalsifiable monster that refuses to lie down and die. According to the more cynical philosophers of science, failed hypotheses, heaped high with anomalies, paradoxes and auxiliary conjectures, are perpetuated by repetition and self-referencing because too many adherents have invested their careers in them. Although many scientists have moved on plumeology remains entrenched conventional wisdom, supported by the publishing industry, with alternative opinions discouraged and made to jump a higher bar. Young scientists who should be encouraged to question dogma are kept in line via hiring, promotion, grant proposal and publication decisions. Zombie research programs defy burial.
One reason for the persistence of the idea of mantle plumes is that nobody seems to have come up with a better explanation for the Hawaiian island chain.
Another similarly beautifully simple idea, that quickly captured people’s imaginations, is that Smoking Causes Lung Cancer. The rising incidence of lung cancer was the result of the rising prevalence of cigarette smoking, which entails inhaling hot, toxic, carcinogenic smoke into the lungs. Wasn’t it obvious? What other explanation was there? More or less overnight, the idea became a new medical dogma, driving a crusade against smoking.
But this simple idea also became a complicated, awkward, messy, unfalsifiable monster. Initially it was just new-fangled cigarettes which were blamed for the lung cancer epidemic, but gradually all tobacco products were blamed for it. So why hadn’t there been a lung cancer epidemic before cigarettes were popularised in the early 20th century? And why is the lung cancer epidemic continuing despite smoking prevalence having fallen drastically over the past 70 years? Why are never-smokers getting lung cancer? What is the precise mechanism by which tobacco smoke (and tobacco smoke alone) causes lung cancer? Why haven’t animal studies been able to produce lung cancer? Why do some smokers get lung cancer, but not others? Aren’t there lots of other possible explanations for the cancer epidemic, including radioactive fallout, HPV, genetic predisposition, and diesel fumes?
Isn’t the cigarette hypothesis another failed hypothesis, heaped high with anomalies, paradoxes and auxiliary conjectures, which is being perpetuated by repetition and self-referencing because too many adherents have invested their careers in it?
And isn’t the same true of the global warming scare? It’s another very simple idea, which is that carbon dioxide in the atmosphere absorbs long wave radiation, causing the atmosphere to warm. It’s so simple that even poor little Greta Thunberg can grasp it.
Perhaps it was ever thus. New ideas of great power and simplicity periodically sweep the world, and launch crusades that drive all before them – until it gradually emerges that these new ideas were themselves just new illusions, new myths.