to be missing, he conceives something which excludes its existence. As he is assumed to be desirous for love's sake of that thing or circumstance (by the last Prop.), he will, in so far as he conceives it to be missing, feel pain (III. xix.). Q.E.D.
Note.—This pain, in so far as it has reference to the absence of the object of love, is called Regret.
PROP. XXXVII. Desire arising through pain or pleasure, hatred or love, is greater in proportion as the emotion is greater.
Proof.—Pain diminishes or constrains a man's power of activity (III. xi. note), in other words (III. vii.), diminishes or constrains the effort, wherewith he endeavours to persist in his own being; therefore (III. v.) it is contrary to the said endeavour: thus all the endeavours of a man affected by pain are directed to removing that pain. But (by the definition of pain), in proportion as the pain is greater, so also is it necessarily opposed to a greater part