If you want to know yourself,
Just look how others do it;
If you want to understand others,
Look into your own heart.

The couplet proposes a double method of self-knowledge and empathy. To know oneself, one should observe one’s conduct as it appears in others—using social interaction as a mirror that reveals habits and motives otherwise invisible from the inside. To understand others, one should consult one’s own heart—recognizing that the basic materials of human feeling (fear, pride, love, resentment) are shared, and that introspection can supply the analogies needed for sympathetic judgment. The balance is characteristic of moral reflection: external observation corrects self-deception, while inward reflection prevents cold, merely “objective” appraisal of other people.