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.
Prop. LXIV. The knowledge of evil is an inadequate knowledge.
Proof.- The knowledge of evil (IV:viii.) is pain, in so far as we are conscious thereof. Now pain is the transition to a lesser perfection (Def. of the Emotions:iii.) and therefore cannot be understood through man's nature (III:vi.,& II:vii.); therefore it is a passive state (III.Def.ii.) which (III:iii.) depends on inadequate ideas; consequently the knowledge thereof (II:xxix.), namely, the knowledge of evil, is inadequate. Q.E.D.
Corollary.- Hence it follows that, if the human mind possessed only adequate ideas, it would form no conception of evil.