Quotes About Congruences

As a rough rule, it seems that writers fall into two camps. There are those who delight in rousting the truth from its concealment amid pieties and convention. If they must strip-mine the world to expose its hypocrisy, they will do so, even if they leave a landscape barren of hope. Then there are those writers who prefer to remythologize life on earth, finding it rich with strange congruences and possibilities.

Mathematicians call it "the arithmetic of congruences." You can think of it as clock arithmetic. Temporarily replace the 12 on a clock face with 0. The 12 hours of the clock now read 0, 1, 2, 3, … up to 11. If the time is eight o'clock, and you add 9 hours, what do you get? Well, you get five o'clock. So in this arithmetic, 8 + 9 = 5; or, as mathematicians say, 8 + 9 ? 5 (mod 12), pronounced "eight plus nine is congruent to five, modulo twelve.