xiii.) there is no modification of the body, whereof we cannot form some clear and distinct conception.
Q.E.D.
Corollary .-- Hence it follows that there is no emotion, whereof we cannot form some clear and distinct conception.

For an emotion is the idea of a modification of the body (by the general Def.

of the Emotions), and must therefore (by the preceding Prop.) involve some clear and distinct conception.
Note .-- Seeing that there is nothing which is not followed by an effect (I.xxxvi.), and that we clearly and distinctly understand whatever follows from an idea, which in us is adequate (II.

xl.), it follows that everyone has the power of clearly and distinctly understanding himself and his emotions, if not absolutely, at any rate in part, and consequently of bringing it about, that he should become less subject to them.

To attain this result, therefore, we must chiefly direct our efforts to acquiring, as far as possible, a clear and distinct knowledge of every emotion, in order that the mind may thus, through emotion, be determined to think of those things which it clearly and distinctly perceives, and wherein it fully acquiesces: and thus that the emotion itself may be separated from the thought of an external cause, and may be associated with true thoughts; whence it will come to pass, not only that love, hatred, &c.