An occasional post of insightful, funny, or outrageous quotes from Human Action.
A surgeon tells a patient who considers submitting himself to an operation that thirty out of every hundred undergoing such an operation die. If the patient asks whether this number of deaths is already full, he has misunderstood the sense of the doctor's statement. He has fallen prey to the error known as the "gambler's fallacy." Like the roulette player who concludes from a run of ten in succession that the probability of the next turn being black is now greater than it was before the run, he confuses case probability with class probability.