Perhaps it was a rule articulated by Cato’s great-grandfather that helped Cato love and support his brother despite their different approaches to life. “I am prepared to forgive everybody’s mistakes,” Cato the Elder said, “except my own.” Ben Franklin, many generations later, would put forth an even better rule: “Search others for their virtues, thyself for thy vices.” Or as Marcus Aurelius put it, Tolerant with others, strict with yourself.