Proof.—Desire (Def. of the Emotions, i.) considered absolutely is the actual essence of man, in so far as it is conceived as in any way determined to a particular activity by some given modification of itself. Hence desire, which arises from reason, that is (III. iii.), which is engendered in us in so far as we act, is the actual essence or nature of man, in so far as it is conceived as determined to such activities as are adequately conceived through man's essence only (III. Def. ii.). Now, if such desire could be excessive, human nature considered in itself alone would be able to exceed itself, or would be able to do more than it can, a manifest contradiction. Therefore, such desire cannot be excessive. Q.E.D.

PROP. LXII. In so far as the mind conceives a thing under the dictates of reason, it is affected equally, whether the idea be of a thing future, past, or present.

Proof.—Whatsoever the mind conceives under the guidance of reason, it conceives under the form of eternity or necessity (II. xliv. Coroll. ii.), and is therefore affected with the same certitude (II. xliii. and note). Wherefore, whether the thing be present, past, or future, the mind conceives it under the same necessity and is affected with the same certitude; and whether the idea be of something present, past, or future, it will in all cases be equally true (II. xli.); that is, it will always possess the same properties of an adequate idea (II. Def. iv.); therefore, in so far as the mind conceives things under the dictates of reason, it is affected in the same manner, whether the idea be of a thing future, past, or present. Q.E.D.

Note.—If we could possess an adequate knowledge of the duration of things, and could determine by reason their periods of existence, we should contemplate things future with the same emotion as things present; and the mind would desire as though it were present the good which it conceived as future; consequently it would necessarily neglect a lesser good in the present for the sake of a greater good in the future, and would in no wise desire that which is good in the present but a source of evil in the future, as we shall presently show. However, we can have but a very inadequate knowledge of the duration of things (II. xxxi.); and the periods of their existence (II. xliv. note.) we can only determine by imagination, which is not so powerfully affected by the future as by the present. Hence such true knowledge of good and evil as we possess is merely abstract or general, and the judgment which we pass on the order of things and the connection of causes, with a view to determining what is good or bad for us in the present, is rather imaginary than real. Therefore it is nothing wonderful, if the desire arising from such knowledge of good and evil, in so far as it looks on into the future, be more readily checked than the desire of things which are agreeable at the present time. (Cf. IV. xvi.)

PROP. LXIII. He who is led by fear, and does good in order to escape evil, is not led by reason.

Proof.—All the emotions which are attributable to the mind as active, or in other words to reason, are emotions of pleasure and desire (III. lix.); therefore, he who is led by fear, and does good in order to escape evil, is not led by reason.

Note.—Superstitions persons, who know better how to rail at vice than how to teach virtue, and who strive not to guide men by reason, but so to restrain them that they would rather escape evil than love virtue, have no other aim but to make others as wretched as themselves; wherefore it is nothing wonderful, if they be generally troublesome and odious to their fellow—men.

Corollary.—Under desire which springs from reason, we seek good directly, and shun evil indirectly.

Proof.—Desire which springs from reason can only spring from a pleasurable emotion, wherein the mind is not passive (III. lix.), in other words, from a pleasure which cannot be excessive (IV. lxi.), and not from pain; wherefore this desire springs from the knowledge of good, not of evil (IV. viii.); hence under the guidance of reason we seek good directly and only by implication shun evil. Q.E.D.

Note.—This Corollary may be illustrated by the example of a sick and a healthy man. The sick man through fear of death eats what he naturally shrinks from, but the healthy man takes pleasure in his food, and thus gets a better enjoyment out of life, than if he were in fear of death, and desired directly to avoid it. So a judge, who condemns a criminal to death, not from hatred or anger but from love of the public well—being, is guided solely by reason.