be defined by the power, whereby we ourselves endeavour to persist in existing, but (as is shown in II. xvi.) must necessarily be defined by the power of an external cause compared with our own. Q.E.D.
PROP. VI. The force of any passion or emotion can overcome the rest of a man's activities or power, so that the emotion becomes obstinately fixed to him.
Proof.—The force and increase of any passion and its persistence in existing are defined by the power of an external cause compared with our own (by the foregoing Prop.); therefore (IV. iii.) it can overcome a man's power, &e. Q.E.D.
PROP. VII. An emotion can only be controlled or destroyed by another emotion contrary thereto, and with more power for controlling emotion.
Proof.—Emotion, in so far as it is referred to the mind, is an idea, whereby the mind affirms of its body a greater or less force of existence than before (cf. the general Definition of the Emotions at the end of Part III.). When, therefore, the mind