Counterintuitive Facts (49): Why Is Sticking to Your Original Intention Often Stupid?

I. We're taught from childhood to "stay true to your original intention," "hold firm beliefs." If someone says east today, then changes to west tomorrow after seeing new situations. We call them "wishy washy," "unprincipled," "swaying with the wind." But in mathematicians' eyes, this "firmness" is often a sign of brain freeze. Because they refuse to run Bayesian Updating.

II. Reverend Thomas Bayes proposed a formula in the 18th century that changed human cognition: P(A|B) = P(B|A) × P(A) / P(B) In plain language: New opinion (posterior probability) = Old opinion (prior probability) × Strength of new evidence (likelihood ratio)

III. This formula tells us: Any opinion is not absolute truth. It's just a temporary "probability bet." Your current opinion (like "housing prices will rise") is jus