Two True Things About Norbert Wiener
Norbert Wiener's theory of feedback grew out of aiming guns at aircraft. A signed essay holds both facts: the idea is true, and its origin is hard to look at.
The Sentence Outside the System
Is understanding just computation with more steps? Roger Penrose says no, and his case runs through Gödel. The weakest point in it comes first.
Four Kinds of Can’t
A million computers running for a million years could not factor a 250-digit number. The line is false, and the number that makes it true shows why "impossible" means four different things.