In disputes upon moral or scientific points, ever let your aim be to come at truth, not to conquer your opponent. So you never shall be at a loss in losing the argument, and gaining a new discovery.

—Arthur Martine, Martine’s Hand-book of Etiquette, and Guide to True Politeness (New York: Dick and Fitzgerald, 1866; repr. Kindle Locations 456—58). (HT: Theocast)