Spotted on Quora, by Paul Mainwood, reposted without permission.
Why is "scientific proof" of climate change so elusive?
Why is "scientific proof" of climate change so elusive?
Because when the challenge is issued: "Where is the scientific proof of climate change?" there's a bait and switch going on. Here's how it works.
There are at least two meanings of the word "proof" in usual English usage. I'm going to call them proof1 and proof2.
proof1: This is the sense used in mathematics: a deductive proof from a set of axioms. In this sense there are no proofs in science (see here as to why: is nothing ever proved in science?)
proof2: This is the sense in which a scientific theory can be "proved", by repeatedly surviving harsh tests that were designed to falsify it.
Most scientists know this. But this makes them even more susceptible to the bait and switch. Try to spot where it happens (clue in advance, it's not where you think it is):
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"Show me scientific proof2 of climate change!"
"Sure, here's some basic thermodynamics and the properties of CO2, some projections of CO2 in the atmosphere and some modelling of global temperature changes based on this. Here's the observed global temperatures against the modelled values."
"No, I mean scientific proof1!"
"Er, do you mean proof1?"
"Yes! Of course."
"Ah, well there is no proof1, you see I have read Hume and Karl Popper, and can happily explain this to you. In science, proof1 does not exist, and we can only ever have proof2. And we have plenty of that proof2 for climate change. In fact, to be precise, anthropocentric global warming is not really a theory in itself but a single prediction based on well-understood theories that have been subjected to lots of proof2"
"Aha, So you admit you have no proof1!"
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Did you spot the bait and switch?
The real bait and switch is not switching proof2 for proof1. The real bait and switch is switching a scientific debate for a philosophical debate.
That is, the trick is to get the scientist to engage on the nature of scientific proof (or even better, on the nature of truth). For once they have started talking about this, they have lost. They have strayed from the ground of authority that science gives them, and have started making philosophical-sounding claims, where everyone knows opinion reigns, truth is relative, and there can be no authority as a basis for public policy.
Substitute "evolution" for "climate change" and the process goes through the same.
The trick is to make the scientists sound elitist, out of touch with reality, and to rob them of the authority that their scientific credentials gives them. And it works every time.
5 comments:
Simply put then, the proof of AGW is that it hasn't been falsified.
Although various skeptics come up with a wide range of contradictory ideas and comments, they really can't be considered "harsh tests that were designed to falsify it [AGW]", nor do they in the end really prove their point.
Most of the discussion I see follows a bit of a different model.
From Lindzen to Monckton to Dyson, the debate is not over physics, not over the actual warming that has occurred. Although you can find some idiots commenting on skeptic blogs, even Anthony Watts does not dispute the physics.
It's all about sensitivity and impacts. People don't get labeled denier because they dispute the physics. They get so labeled because they don't sign on to policy prescriptions or high end estimates of atmospheric sensitivity. That's why James Hansen and Barack Obama, Kevin Trenberth and Andrew Revkin can get called deniers.
It doesn't work every time.
But you need scientists savvy enough to know when they're being set up by someone arguing in bad faith. Then the reply is "that's not the way physical science works" followed by a reiteration of the main points. One could always then pointedly refer back to the various weak, muddled or contradictory explanations offered by skeptics and contrarians (it's the Sun... it's volcanoes... it's natural variation... it's the stadium wave... it's the oceans burping... what warming?... etc.)
Oh, c'mon - Global Warming is easily proved:
1) the amount of heat radiated into space from the Earth is less than the heat equivalent of the energy of the Sun which is absorbed by the Earth.
Q.E.D.
That it is anthropogenic is easily proved also - the stoichiochemistry of barrels of oil burned correlates with [atmospheric carbon] which correlates with what Greenhouse physics says is the extra heat content causing Earth's energy imbalance.. And, the carbon isotope analysis of atmospheric CO2 proves it was burned recently.
Game. set. match.
All the rest is evidence - SLR, melting ice, migration of animals and growing zones, increased water content of the atmosphere and intense weather, rising temperatures on land and in sea, etc, etc.
A consilience of evidence confirming the direct physical measurements of 1). Ask a denier to disprove 1), they change the topic.
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