An emotion is a tendency to feel, and an instinct is a tendency to act, characteristically, when in the presence of a certain object in the environment. But the emotions also have their bodily "expression," which may involve strong muscular activity (as in fear or anger, for example); and it becomes a little hard in many cases to separate the description of the "emotional" condition from that of the "instinctive" reaction which one and the same object may provoke.... Every object that excites an instinct excites an emotion as well. The only distinction one may draw is that the reaction called emotional terminates in the subject's own body, whilst the reaction called instinctive is apt to go farther and enter into practical relations with the exciting object.
