It is sometimes said that Charles Darwin has a theory of emotional expression, but not a theory of emotion. This paper argues that Darwin does have a theory of emotion. Inspired by David Hartley and Erasmus Darwin, Charles Darwin claims that an emotion is a train of feelings, thoughts, and actions, linked by associations. Whereas Hartley and Erasmus insist that these associations are learned, Charles proposes that some of these associations are inherited. He develops this theory in his private notebooks (...) from 1838–1839 and then assumes it in The Expression of the Emotions in Man and Animals (1872). (shrink)