Each year, the website Edge poses a single thought-provoking question to hundreds of different intellectuals — scientists, philosophers, authors, journalists, poets — then collects and posts their replies online for the general public to read. Past questions include “What do you believe is true even though you cannot prove it?”, “What are you optimistic about?” “What scientific  concept would improve everybody’s cognitive toolkit?” Past contributors include Nassim Nicholas Taleb, Alison Gopnik, Lawrence Krauss, Rebecca Newberger Goldstein, Richard Dawkins, Carolyn Porco, Daniel Dennett, Steven Pinker, Jared Diamond, and many others. This year’s question was “What scientific idea is ready for retirement?” There are 174 responses and, while I have no illusion of reading them all any time soon, a couple have either caught my eye or been brought…