Augustus De Morgan

Augustus De Morgan (1806–1871) was a British mathematician and logician, a brilliant teacher, and a lifelong contrarian who once refused an honorary degree and a seat in the Royal Society on principle. He helped drag logic into the modern age and left behind a pair of rules every programmer eventually meets.

The stroke of genius

De Morgan's laws are the little identities that let you flip a NOT across an AND or an OR — the everyday tools of Boolean algebra. "Not (A and B)" becomes "not A or not B," and vice versa. He was a friend and champion of George Boole, whose logic of true and false underlies every circuit. De Morgan also coined the term "mathematical induction," giving that proof technique its name.

De Morgan loved a numerical puzzle. He liked to point out that he was x years old in the year x^2 — which pins his birth neatly to 1806, since 43^2 = 1849. Blind in one eye from birth and shy in a crowd, he nonetheless became one of the great lecturers of his day, and he taught Ada Lovelace her advanced mathematics by post.