Jean-Henri Casimir Fabre (1823-1915) was a fiercely independent thinker who had a slavish drive for scientific truth. He was what you’d call an autodidact – a self-educated man who picked his own path to becoming a physicist, a chemist, a botanist, and an etymologist. In a thinking man’s way, he questioned ideas like the paradox of Buridan’s Ass, a concept oft quoted in the schools of his day to illustrate the ironies of free will. One version of the paradox went like this: If you take a donkey that is equally starved and equally thirsty and sit him between water...