No More Learning

Whether or NOT the Japanese empire took seriously the resource em- bargo threatened by Roosevelt (that is, attack the United States), whether or NOT Vice Admiral Nagumo's           would sink the Pacific battleships at Pearl Harbor with carrier-bound aircraft, whether or NOT he would maintain silence in his areas of operation off the Aleutian Islands (he did): these were precisely the digital puzzles of 194 1 , solvable only through the interception and decoding of necessarily discrete sources of information.