There’s only one requirement of any of us, and that is to be courageous. Because courage, as you might know, defines all other human behavior. And, I believe - because I’ve done a little of this myself - pretending to be courageous is just as good as the real thing.

Letterman frames courage as a foundational virtue: the quality that enables (and in a sense “defines”) all other forms of human conduct—honesty, kindness, perseverance—because each requires the willingness to risk discomfort, failure, or judgment. The second half adds a characteristically wry twist: he suggests that “pretending” to be brave can function like real bravery. This points to a pragmatic, behavioral view of virtue—if you act courageously, the effects in the world (and on your own habits) may be similar regardless of whether you felt fearless inside. It also acknowledges performance and self-doubt as common parts of public life, while still urging action over paralysis.