Full Idea
Direction, scope and focus set the stage, but the specific object is what defines the emotion.
Gist of Idea
Emotions are defined by their objects
Source
Robert C. Solomon (The Passions [1976], 7.3)
Book Reference
Solomon,Robert C.: 'The Passions (1993 ed)' [Hackett 1993], p.200
A Reaction
This is presumably the main distinction between an emotion and a mood. He emphasises that the objects are subjective, rather than factual.