PROP. XL. Whatsoever conduces to man’s social life, or causes men to live together in harmony, is useful, whereas whatsoever brings discord into a State is bad.

Proof.—For whatsoever causes men to live together in harmony also causes them to live according to reason (IV. xxxv.), and is therefore (IV. xxvi. xxvii.) good, and (for the same reason) whatsoever brings about discord is bad. Q.E.D.