There is no such thing as “settled science”
“Climate warming is settled science, and we should no longer question it. Rather, we should proceed to implement major public policy changes and incur large expenses to mitigate the harm that global warming will create.” This is frequently asserted by those who see great danger in the possibility of climate change.
But they are wrong, in many ways. For one thing, science is never “settled.”
If you don’t believe me, ask Newton. His laws of motion were accepted from 1642 until 1905 Then, along came Einstein, who said: “Not quite.” In the theory of special relativity, he did not assert that Newton was wrong, simply that the laws of motion as formulated by Newton were not applicable to bodies moving at speeds near to the velocity of light. (In fact the Newtonian formulation is so accurate at slower velocities that NASA continues to rely on it to guide its flights to the moon and other destinations.) For objects moving at speeds near the speed of light, a modification was needed, which Einstein proposed and others subsequently proved correct by experiment and observation.
This story was largely repeated with respect to the law of gravity. Once again Newton’s formulation was the best we had for several centuries, and it worked just fine in the context of our everyday lives. But trouble had arisen both at the subatomic scale and at the intergalactic scale. in the 1920s, Einstein came along agian, this time with the general theory of relativity. After decades of experiments, some of the basic predictions of the general theory were confirmed. The physics of this is still unresolved: something called ‘string theory’ is supplying some clues. But, whatever the resolution of these problems, it is abundantly clear that the science is not “settled”.
Science is made in the laboratory, not in the voting booth.
Those who see great danger in the possibility of climate change assert that there is consensus among scientists that human activities are causing deleterious climate change. This may or may not be so. But consensus is totally irrelevant to science.
If you don’t believe me, ask Galileo. In the fifteenth century, he and some colleagues (Brahe, Kepler and a few others) looked into the sky with their newly invented telescopes, measured what they saw and concluded that the earth revolved around the sun. Two popes and 15,000,000 Catholics believed the opposite – that the sun revolved around the earth. That sounds like consensus to me. But the consensus was wrong. (This didn’t help Galileo very much. He was put under house arrest for the rest of his life for refusing to recant except in a pro forma way.)
Observation trumped theology, and consensus had nothing to do with it.
Science has limits that are much narrower than most people understand.
Every scientific ‘law’ is ultimately based on experiments performed or observations made in the real world, which is to say within some environment larger than the experiment itself. Thus an assertion such as “Newton’s Laws of Motion are correct” is really shorthand for “Newton’s Laws of Motion are correct for objects that are observable by eye, by microscope or by telescope.” They say nothing about atoms or intergalactic dust clouds.
Another way of saying this is: it is scientifically legitimate to interpolate existing scientific laws (you will be right most of the time) but not to extrapolate them (you will be wrong much of the time.)
We will return to the limits of science in the context of other issues as they arise.
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