"All Theories Are False"
By Bryan Caplan
I can’t tell you how many times natural and social scientists have solemnly told me, “All theories are false.” Their “proof” usually amounts to the solitary example of Newtonian physics, proven false by Einsteinian physics. But if you’re patient, they eventually just say, “Look, no theory perfectly fits the facts. That makes them all false.”
My reply: You’re right if “true” means true to an infinite number of decimal places in all conceivable circumstances. But that’s a ridiculous standard of truth. In ordinary language, a statement is true as long as the world lies inside a range under normal conditions.
Ex: If a farmer tells me that town is 5 miles away, I don’t call him a liar if the actual distance is 4.932764 miles. And I don’t call him a liar if, as the crow flies, the town is only 4.167467 miles away. When you roll down your car window and ask for the distance, it’s understood that you aren’t asking for the distance by chopper or subterrene. Of course, if you specified “exactly 5 miles” or “under all conceivable conditions,” or “always” you’re holding yourself up to much higher standards.
While we’re on the subject, I might as well dispose of a related fallacy: “Claims cannot be proven true, only proven false.” This is often correct if you’re making universal claims, like “All X are Y,” (though even that might be proven true if the X’s are narrowly defined). But for existence claims, like “Some X are Y,” the opposite holds: You can prove the claim true, but cannot prove it false.
What are sophistries about the falsity and unprovability of everything so popular? I think the main motivation behind these claims is what Tyler calls “mischievousness.” Some thinkers take perverse delight in declaring that everyone is wrong and nothing can be proven. It allows them to rhetorically expropriate rival meritorious thinkers in one fell swoop without making enemies with anyone in particular. Don’t let them get away with it.