The unassailable science behind ‘theories’
Science can make life difficult for manipulators and demagogues. Without science, it would be much easier to convince the public that an intelligent designer created the world, or that greenhouse gas warming and lead contamination are just the fantasies of “alarmists.”
To physicist and historian Gerald Holton, attacks on science tend to go along with moves toward authoritarian rule. “History has shown repeatedly that a disaffection with science and its view of the world can turn into a rage that links up with far more sinister movements,” he wrote in his 1993 book Science and AntiScience.
Those who want to fight the conclusions of scientific research often strike at its points of vulnerability — such as scientists’ insistence on using the word “theory” to describe even well-established ideas. In popular language, a “theory” implies a hunch or guess — something less than a fact. That wrongly suggests weakness. “The theory of global warming is just that: a theory,” thencongressman and climate skeptic Mike Pence told an Indiana newspaper in 2003.
“It’s unfortunate the way the word ‘theory’ is used,” said philosopher of science Peter Godfrey-Smith. “To say something is a theory is to say it’s been expressed as an idea. It’s not to say anything about whether the claim is justified or not justified — true or false.”
The theory behind climate change is grounded in observation and reason. By the early 1800s, physicists realized that an Earth-sized rock orbiting the sun at a distance of 93 million miles should be frozen according to the known laws of physics. French physicist Joseph Fourier proposed that the atmosphere keeps the planet warm. Others tested this theory in laboratory experiments, sending a simulated version of sunlight through various gases. In repeated experiments, carbon dioxide absorbed and re-radiated infrared waves, which on a planetary scale would prevent some of the sun’s energy from escaping to space. But now climate science has something even stronger on its side, said atmospheric physicist Lee Harrison of the State University of New York, Albany.
The premise is all predicted by a powerful theory in physics known as quantum mechanics, which describes in detail the behaviour of light and matter on the scale of molecules, atoms and subatomic particles. Like Einstein’s theory, quantum mechanics is bolstered by hundreds of experiments. Quantum mechanics predicts how infrared radiation coming up from the earth will be affected by carbon dioxide and other gases. “What the public doesn’t understand is the extreme interconnectedness of physical reality,” Harrison said. “If someone proposes that carbon dioxide is not a greenhouse gas, this requires ripping up essentially all of modern physics.”
The misperception skewing today’s debate over climate change is confusion between uncertainty about the predictions of a theory and uncertainty about the theory itself. To illustrate the difference, Harvard University philosopher Peter Galison brings up evolution by natural selection: the theory is on solid ground, but that doesn’t mean it can predict exactly what foxes will look like 800,000 years in the future.