אתיקה, חלק V, משפט 3

An emotion, which is a passion, is a confused idea (by the general Def. of the Emotions). If, therefore, we form a clear and distinct idea of a given emotion, that idea will only be distinguished from the emotion, in so far as it is referred to the mind only, by reason (II. xxi., and note); therefore (III. iii.), the emotion will cease to be a passion. Q.E.D.

An emotion therefore becomes more under our control, and the mind is less passive in respect to it, in proportion as it is more known to us.