Elon Musk: With 110 million followers and a particular kind of genius, the gnomic utterances of the world’s richest man can knock normal, intelligent people off their axis for hours. Photograph: Brian Lawless/PA Those who have not succumbed to Twitter have probably made a wise choice. They still believe that most human exchanges are conducted in good faith. They go to sleep on schedule, with an unjangled mind. Then again, they missed the single-word tweet dropped by Elon Musk on Monday. In Greek. The word translates as “dialectic”, ie reasoning, contention, the art of investigating the truth of opinions. Was...