The World Question Center posed the question recently: What scientific concept would improve everyone’s cognitive toolkit? The list of contributions is here. The contributors were mostly public intellectuals, which generally means scientists or science writers who have written books for the general public. I’ve only casually browsed through them and there are some interesting entries. I liked the contributions of Nick Bostrom, Robert Sapolsky and Nigel Goldenfeld. Unfortunately, or perhaps intentionally, they are not listed in alphabetical order. However, I think a lot of the entries were rather sophisticated and philosophical. I would propose something simple that everyone should know but doesn’t like the classical logical constructions known as Modus Ponens and Modus tollens, which together say that if A implies B then the only conclusions that can be drawn are that if A is true then B is true and if B is not true then A is not true. More pertinently, A is not true does not say anything about B. I would venture that most people, including scientists, cannot keep that straight.