Full Idea
Emotion returns to its object every moment, and feeds upon it. …The emotional subject and the object of the emotion are united in an indissoluble synthesis. Emotion is a specific manner of apprehending the world. …[39] It is a transformation of the world.
Gist of Idea
An emotion and its object form a unity, so emotion is a mode of apprehension
Source
Jean-Paul Sartre (Sketch for a Theory of the Emotions [1939], §III)
Book Reference
Sartre,Jean-Paul: 'Sketch for a Theory of Emotions' [Routledge 1994], p.35
A Reaction
The last sentence is the essence (or existence?) of Sartre's core theory of the emotions. They are, it seems, a mode of perception, like a colour filter added to a camera. I don't think I agree. I see them as a response to perceptions, not part of them.
Related Idea
Idea 24014 Emotions are a sort of bodily incantation which brings a magic to the world [Sartre]