P41: Joy is not directly evil, but good; Sadness, on the other hand, is directly evil.

Dem.: Joy (by IIIP11 and P11 S) is an affect by which the body’s power of acting is increased or aided. Sadness, on the other hand, is an affect by which the body’s power of acting is diminished or restrained. And so (by P38) joy is directly good, etc., q.e.d.