The Two Great Truths of the modern world are, firstly, that Smoking Causes Lung Cancer, and secondly, that Carbon Dioxide Causes Global Warming. Both are regarded as being the kind of Settled Science of which only the ignorant and uneducated are unaware.
And if there is one difference between “Progressives” and “Conservatives”, it is that progressive people will readily accept and adopt every advance in Science as soon as they are announced, while conservative people will not immediately accept new scientific doctrines.
And we are at present witnessing in France the collision between a progressive French President, Emmanuel Macron, and the rather more conservative French people. For Emmanuel Macron is someone who has accepted and adopted both the doctrine that Smoking Causes Lung Cancer, and the doctrine that Carbon Dioxide Causes Global Warming – while it would appear that a great many French people have not. As far as Macron is concerned, these Two Great Truths are simply Settled Science. And he probably believes that if the French people were as educated and enlightened as he himself is, they would understand and accept the necessity of stamping out smoking, and stamping out carbon dioxide.
Almost everybody (in the western world at least) believes that Smoking Causes Lung Cancer because they have been incessantly told this by doctors and epidemiologists and scientists and pundits and the mass media for the past 70 years and more. The doctrine that Smoking Causes Lung Cancer swept the western world in the 1950s, and had become Settled Science by the mid-1960s. Hardly any sceptics (like Sir Ronald Fisher) managed to hold out for very long against the triumphant advance of the New Science.
The doctrine that Carbon Dioxide Causes Global Warming has not been quite so successful in its triumphant advance. For if there are considerable numbers of believers in this new doctrine, there are also considerable numbers of sceptics or “deniers”. And this may simply be because, unlike with the other Great Truth, scientists and pundits and the mass media have only been aggressively promoting the doctrine for the past 30 years, rather than the past 70+ years. And it may also be that, in the age of the pluralistic and conversational internet, it has become impossible for a single megaphone mass media message to be broadcast for public consumption.
One of the interesting things about the Two Great Truths is that the most widely accepted of the two – that Smoking Causes Lung Cancer – is actually the least scientific. For it’s a doctrine that rests entirely on a probabilistic and statistical argument, which is that the rise in cigarette smoking in the western world was followed a few decades later by a rise in the incidence of lung cancer, and that the first of these events was the cause of the second. But the proponents of this idea have never offered any causal explanation for this. They have never explained exactly how smoking causes lung cancer, how tobacco smoke enters into cells and causes them to multiply explosively in numbers. Nor have they ever offered any explanation why some smokers (e.g. Jeanne Calment) did not contract lung cancer despite smoking for almost all their very long lives.
The second Great Truth – that Carbon Dioxide Causes Global Warming – is a doctrine which offers a causal explanation for the warming, which is that carbon dioxide absorbs long wave radiation from the warm surface of the Earth, preventing its escape to outer space, and resulting in the warming of the atmosphere of the Earth. This is a far more scientific explanation, and it is also generally not accompanied by probabilistic and statistical arguments. And the argument between global warming alarmists and sceptics is generally not about whether the warming is happening in the manner described, but rather about the degree to which the warming is happening, and the dangers posed by it.
The fact that there is a scientific explanation for global warming has allowed me to construct my own rather simple computer simulation model of the Earth, with the Sun shining on its surface, and heat being radiated from the warm surface into the atmosphere. Some 40 years ago I used to build heat flow models of this sort, so I have a fairly good idea how to do it. And I have seen the warming happening in my model, when I increase the absorptivity of its atmosphere: Cranking the absorptivity of the atmosphere up to its maximum can result in 20 – 30ºC rises in air temperatures. But such maximum absorptivities would seem to only be found with very high concentrations of CO2 in the atmosphere (like on Venus where the atmosphere is almost entirely carbon dioxide, and the planet is very hot). It’s not clear to me that the far lower concentrations of CO2 in the Earth’s atmosphere, in the order of a few hundred parts per million, are sufficient to produce such high rises in temperature.
However it’s not possible for me (or anyone else) to build a computer simulation model of the flow of tobacco smoke into human lungs, and thence into lung cells, and thence to interfere in the processes of cell growth and division, because there are no detailed explanations of the process. There’s no science that can be modelled and replicated. There is only the assertion that, somehow or other, tobacco smoke causes some lung cells to multiply rapidly.
So there’s the odd circumstance that the first Great Truth, which everybody believes, and about which there is no public debate whatsoever, rests upon the most tenuous mathematical foundations – while the second Great Truth, which a great many people do not believe, and is the subject of highly contentious public debate, rests upon a remarkably solid and detailed scientific foundation.
But perhaps this might explain why there is such a spirited debate about the one, but dead silence about the other. For it is only possible to argue against any explanation of anything if there actually is some sort of coherent explanation. For once the climate scientists set out their detailed explanations of how global warming could happen, it became possible to question many of the assumptions underlying their model (e.g. the sensitivity of air temperatures to CO2 concentrations), and to point out the failures of their simulation models (all of which seem to predict far more warming than is actually happening). But because there is no explanation whatsoever of how smoking causes lung cancer, it is quite impossible to question the assumptions underlying this model, or its failures to replicate the real world. For there is no explanation, and there is no model. There is just the dogmatic assertion, now widely printed on tobacco products, that Smoking Causes Lung Cancer.