On Galileo Galilei and “denialism” from elections to climate to COVID

Galileo Galileo has many self-appointed intellectual heirs these days. Whether it’s a claim that the election has been stolen, that COVID-19 is less fatal than the flu, that climate change or evolution are hoaxes, or that P=NP, we keep hearing from people considering themselves as bold truth-tellers railing against conventional wisdom. We are encouraged to “teach the debate” and that if only paid attention, we will see that their Tweet, declaration, or arxiv paper contains an irrefutable proof of their assertions.

In the words of Ted Cruz, “They brand you a heretic. Today, the global warming alarmists are the equivalent of the flat-Earthers. It used to be [that] it is accepted scientific wisdom the Earth is flat, and this heretic named Galileo was branded a denier”.

Of course by Galileo’s time it was well known that the earth was spherical, and Magellan circumnavigated the earth more than 40 years before Galileo was born. But putting aside Cruz’s confusion of flat earth and geocentrism, the story of heliocentric theory is not one of an outsider railing against the scientific mainstream. Galileo himself was a chaired professor of mathematics at the University of Padua, and later philosopher and mathematician to the grand duke of Tuscany. He was very much part of the scientific establishment of his time. Moreover, though Galileo did provide important evidence for heliocentrism, he was not the only one doing so. Kepler found a heliocentric model with elliptical orbits that actually made correct predictions, and, though it took a decade or so, Kepler’s book eventually became the standard textbook for astronomy.

My point in this post is not to rehash the history of heliocentrism or Galileo but rather to call out a misconception which, to use Sean Carrol’s phrasing, amounts to valorization of puzzle-solving over wisdom.

It is tempting to think that an argument, regardless whether it comes from an expert or a random person on Twitter, can be presented in a self-contained way and judged on its merits. However, this is not how things work in any interesting setting. Even in the case of a purported P vs NP proof, there is background knowledge on computational complexity without which it would be hard to spot holes in the argument. This is doubly so for any claim involving empirical facts, whether it’s about elections, infections, climate etc. It is not possible to evaluate such claims without context, and to get this context you need to turn to the experts that have studied the topic.

I have written before in defense of expertise (see also here) but Carroll puts it very well. Another way to say it is that the operational interpretation of the common refrain

Extraordinary claims require extraordinary evidence

is

Treat claims conforming to conventional wisdom with charity, and claims disputing it with skepticism.

(There is a question of how to define “conventional wisdom” but interestingly there is usually agreement in practice by both sides. Most “deniers” of various sorts are proud of going against conventional wisdom, but don’t acknowledge that this means they are more likely to be wrong.)

As an example, even if someone has expertise in analytic number theory, and so presumably has plenty of so-called “puzzle-solving intelligence”, that doesn’t mean that they can evaluate a statistical claim on election fraud and their analysis should be considered evidence (apparently at this point the number theorist himself agrees). We can try to read and debunk what they wrote, or we can assume that if there was evidence for large-scale fraud, then the president of the United States and his well-funded campaign would have managed to find actual statisticians and experts on election to make the case.

There can be debate if Trump’s attempt to overthrow the election should be considered as dangerous or merely absurd, but the constant attacks on the very notions of truth, science, and expertise are causing far-reaching harm.

(H/T: Scott Aaronson, who makes a similar point around the election conspiracies.)