Probability

Abstract

The subject of probability reminds one of that Australian curiosity enjoying the orotund and circus-stirring name of “ornithorhyncus Paradoxus or duck-billed Platypus”—is it fish or fowl or beast?” Like the sacred cod of Boston this strange animal lives in the water; like the royal swans of his Britannic majesty, it has a flat bill, web-feet, and lays white shell-encased eggs; like the tiger of Kipling's Jungle Tales it has soft fur and suckles its young. And beside all this the male has spurs like a rooster. In a somewhat analogous way, probability, like the quadratic equation, or the removal of parentheses, is a subject in textbooks on algebra. Along with partial differential equations it is one of the advanced topics in mathematical physics. In connection with statistics it comes under education, economics, psychology, biology, or mathematics. It is studied in the theory of manufacturing practice, and in describing the operation of genetic inheritance. It proves absorbing to the dissolute gambler, while the philosopher treats it as an abstruse item of theoretical logic. It is invoked in casual comments about the weather, explained in treatises on practical surveying, and constitutes one of the first principles in the rational discussion of old age pensions, and of business cyles. Is it not strange that to explain how heat causes water to boil, one may well consider first the effect of tossing coins? Where else in algebra is any such economic prudence as that of life insurance brought home to the student, and where else is he asked to contemplate games of dice, gambling at Monte Carlo, and luck in drawing cards for poker?