Galileo on Critical Thinking and the Folly of Believing Our Preconceptions – The Marginalian

… nearly half a millennium before Carl Sagan crafted his Baloney Detection Kit, Galileo established himself as humanity's premier nonsense-buster and made it his chief mission to counter ignorance and indolence with critical thinking — something crisply articulated in the words of one of the book's fictional protagonists:

In the long run my observations have convinced me that some men, reasoning preposterously, first establish some conclusion in their minds which, either because of its being their own or because of their having received it from some person who has their entire confidence, impresses them so deeply that one finds it impossible ever to get it out of their heads. Such arguments in support of their fixed idea as they hit upon themselves or hear set forth by others, no matter how simple and stupid these may be, gain their instant acceptance and applause. On the other hand whatever is brought forward against it, however ingenious and conclusive, they receive with disdain or with hot rage — if indeed it does not make them ill. Beside themselves with passion, some of them would not be backward even about scheming to suppress and silence their adversaries.

Many centuries later, trailblazing physicist and chemist Michael Faraday issued an equally impassioned clarion call for countering our propensity for self-deception — a propensity powered by what modern psychologists have termed "the backfire effect."

Dialogue Concerning the Two Chief World Systems brims with a wealth more of Galileo's enduring legacy of critical thinking. Complement it with I, Galileo — a marvelous picture-book about the life of the great scientist — then revisit John Dewey on the art of reflection in the age of instant opinions and Malcolm Gladwell on the importance of changing your mind.

https://www.themarginalian.org/2015/10/08/galileo-dialogue-critical-thinking/