Eleanor Roosevelt had a great rule. We must do the thing we cannot do, she said. And if you look at her life, she more or less followed this rule. She conquered her shyness and became a leading public figure. She overcame sexism and preconceptions about the role of a First Lady—a job she never wanted—to turn it into a powerful pulpit for good. She forgave her husband’s betrayals and affairs, even though they absolutely crushed her. Even in childhood she overcame obstacles and proved resilient — both her parents and one brother died while she was young, and yet she persisted onward. Each time she was faced with limitations, internally or externally, she managed to transcend them. She pushed past her fears, her reservations, and the doubts of others. This was what made her great. What the Stoics wanted us to know is that we are capable of far more than we know. We can do far more than anyone else thinks. We have great strength and power within us, if only we choose to seize it. If only we ignore that “can’t/don’t/won’t/shouldn’t” voice in our heads. Whether you’re looking at the life of Marcus Aurelius—which was marked with countless betrayals and setbacks—or the tortuous ordeal of James Stockdale—which was a nearly inhuman trial—you see men (and women) doing things that no one thought they could do. Things that, at the outset, even they probably didn’t think they could do.And yet they forgave—both those who doubted them and those who assailed them. They saw the best in people. They insisted on principle. They survived. They didn’t break. And we are heirs to that tradition. We have the ability to live by Eleanor Roosevelt’s dictum. Do the thing you cannot do. Starting today.