This Element explains Kant's distinction between rational sympathy and natural sympathy. Rational sympathy is regulated by practical reason and is necessary for adopting as our own those ends of others which are contingent from the perspective of practical rationality. Natural sympathy is passive and can prompt affect and dispose us to act wrongly. Sympathy is a function of a posteriori productive imagination. In rational sympathy, we freely use the imagination to step into others' first-person perspectives and associate imagined intuitional contents with the concepts others use to communicate their feelings. This prompts feelings in us that are like their feelings.