Francis Bacon on confirmation bias

Nowadays, we call it “confirmation bias:” our deep-seated tendency to prefer information that confirms our existing positions. A political controversy erupted in 2010 when the libertarian blogger Julian Sanchez accused conservatives of falling prey to “epistemic closure,” which was his preferred term for the same problem:

Reality is defined by a multimedia array of interconnected and cross promoting conservative blogs, radio programs, magazines, and of course, Fox News. Whatever conflicts with that reality can be dismissed out of hand because it comes from the liberal media, and is therefore ipso facto not to be trusted.

Edward Glaesser and Cass Sunstein call this phenomenon “asymmetric Bayesianism” and give examples from the left as well as the right. I argued earlier this week that Amy Chua’s and Jed Rubenfeld’s book The Triple Package suffers from the same problem.

But–as is often the case–Francis Bacon got there first. In his remarkable compendium of human cognitive frailties (published in 1620), he included this problem:

The human understanding when it has once adopted an opinion (either as being the received opinion or as being agreeable to itself) draws all things else to support and agree with it. And though there be a greater number and weight of instances to be found on the other side, yet these it either neglects and despises, or else by some distinction sets aside and rejects, in order that by this great and pernicious predetermination the authority of its former conclusions may remain inviolate. And therefore it was a good answer that was made by one who, when they showed him hanging in a temple a picture of those who had paid their vows as having escaped shipwreck, and would have him say whether he did not now acknowledge the power of the gods — “Aye,” asked he again, “but where are they painted that were drowned after their vows?” And such is the way of all superstition, whether in astrology, dreams, omens, divine judgments, or the like; wherein men, having a delight in such vanities, mark the events where they are fulfilled, but where they fail, though this happen much oftener, neglect and pass them by. But with far more subtlety does this mischief insinuate itself into philosophy and the sciences; in which the first conclusion colors and brings into conformity with itself all that come after, though far sounder and better. Besides, independently of that delight and vanity which I have described, it is the peculiar and perpetual error of the human intellect to be more moved and excited by affirmatives than by negatives; whereas it ought properly to hold itself indifferently disposed toward both alike. Indeed, in the establishment of any true axiom, the negative instance is the more forcible of the two.

 (Novum Organon, XLVI) 

Of course, Bacon’s goal was not lament our tendency to err but to help us fix it. Evidence has accumulated to reinforce his concerns about our blinkers and biases. Yet, as the Yale psychologist Paul Bloom recently wrote in The Atlantic, even the accumulated evidence does not show that we are fundamentally irrational. We very often make wise and deliberate choices. It all depends on the context of choice and the methods we use to deliberate:

So, yes, if you want to see people at their worst, press them on the details of those complex political issues that correspond to political identity and that cleave the country almost perfectly in half. But if this sort of irrational dogmatism reflected how our minds generally work, we wouldn’t even make it out of bed each morning.

As the heirs of Bacon’s scientific revolution, we should relentlessly investigate all systematic forms of human error–not to shake our faith in reason but to help us to reason better.

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About Peter

Associate Dean for Research and the Lincoln Filene Professor of Citizenship and Public Affairs at Tufts University's Tisch College of Civic Life. Concerned about civic education, civic engagement, and democratic reform in the United States and elsewhere.