By Bryan Caplan
Suppose you publicly declare, “X causes Y.” If people have strong emotions about X or Y, they’re likely to misinterpret you in at least one of the following ways.
1. Misinterpretation of certainty: “So X certainly causes Y.”
Reply: Who said anything about certainty? In normal English, assertions are not certain. That’s why people will often hear a statement, then request further information about your confidence. As in: “Are you certain of that?” or even “Are you absolutely certain of that?”
2. Misinterpretation of necessity: “So X necessarily causes Y.”
Reply: Who said anything about necessity? In normal English, assertions describe what is, not what must be.
3. Misinterpretation of universality: “So every X causes Y.”
Reply: Again, who said anything of the kind? In normal English, assertions describe what typically happens, not what invariably happens.
4. Misinterpretation of monocausality: “So every Y is caused by X.”
Reply: In normal English, naming one cause does not preclude the existence of endless other causes.
5. Misinterpretation of hyperbole: “So even a grain of X causes tons of Y.”
Reply: Again, naming X as a cause of Y says nothing about how responsive Y is to X.
Given how childish all of these misinterpretations seem, why do they run rampant? The best story, in my view, is that these misinterpretations are offshoots of simpler forms of motivated reasoning. As Jonathan Haidt observes, when we hear a statement we want to believe, we usually ask ourselves, “Can I believe it?” When we hear a statement we don’t want to believe, in contrast, we usually ask ourselves, “Must I believe it?”
My extension: When we want to believe that “X causes Y,” we rarely impute any of the preceding misinterpretations to the speaker. After all, misinterpretations make it harder to answer “Can I believe it?” affirmatively. In contrast, when we don’t want to believe “X causes Y,” the Great Misinterpretations are exceedingly helpful. Once we inject the humble claim that “X causes Y” with spurious certainty, necessity, universality, monocausality, or hyperbole, the answer to “Must I believe it?” is bound to be “No.”
What’s the better epistemic path?
The obvious step: Don’t selectively ask “Can I believe it?” or “Must I believe it?” Instead, just ask, “What’s the probability?”
The less obvious step, though, is: Before you assign probabilities, listen to the speaker’s precise words. If he didn’t claim certainty, necessity, universality, monocausality, or hyperbole, he probably believes none of them. So don’t pretend otherwise!