Ética, Parte IV, Proposição 53

Humility is pain arising from a man's contemplation of his own infirmities (Def. of the Emotions, xxvi.). But, in so far as a man knows himself by true reason, he is assumed to understand his essence, that is, his power (III. vii.). Wherefore, if a man in self--contemplation perceives any infirmity in himself, it is not by virtue of his understanding himself, but (III. lv.) by virtue of his power of activity being checked. But, if we assume that a man perceives his own infirmity by virtue of understanding something stronger than himself, by the knowledge of which he determines his own power of activity, this is the same as saying that we conceive that a man understands himself distinctly (IV. xxvi.), because[14] his power of activity is aided. Wherefore humility, or the pain which arises from a man's contemplation of his own infirmity, does not arise from the contemplation or reason, and is not a virtue but a passion. Q.E.D.

1. [14] Land reads: "Quod ipsius agendi potentia juvatur"--which I have translated above. He suggests as alternative readings to 'quod', 'quo' (= whereby) and 'quodque' (= and that).