Prop. LXV. Under the guidance of reason we should pursue the greater of two goods and the lesser of two evils.
Proof.- A good which prevents our enjoyment of a greater good is in reality an evil; for we apply the terms good and bad to things, in so far as we compare them one with another (see preface to this Part); therefore, evil is in reality a lesser good; hence under the guidance of reason we seek or pursue only the greater good and the lesser evil. Q.E.D.
Corollary.- We may, under the guidance of reason, pursue the lesser evil as though it were the greater good, and we may shun the lesser good, which would be the cause of the greater evil. For the evil, which is here called the lesser, is really good, and the lesser good is really evil, wherefore we may seek the former and shun the latter. Q.E.D.
Prop. LXVI. We may, under the guidance of reason, seek a greater good in the future in preference to a lesser good in the present, and we may seek a lesser evil in the present in preference to a greater evil in the future. "Maltim praesens minus prae majori futuro." (Van Vloten). Bruder reads: "Malum praesens minus, quod causa est faturi alicujus mali." The last word of the latter is an obvious misprint, and is corrected by the Dutch translator into "majoris boni." (Pollock, p. 268, note.)
Proof.- If the mind could have an adequate knowledge of things future, it would be affected towards what is future in the same way as towards what is present (IV:lxii.); wherefore, looking merely to reason, as in this proposition we are assumed to do, there is no difference, whether the greater good or evil be assumed as present, or assumed as future; hence (IV:lxv.) we may seek a greater good in the future in preference to a lesser good in the present, &c. Q.E.D.
Corollary.- We may, under the guidance of reason, seek a lesser evil in the present, because it is the cause of a greater good in the future, and we may shun a lesser good in the present, because it is the cause of a greater evil in the future. This Corollary is related to the foregoing Proposition as the Corollary to IV:lxv. is related to the said IV:lxv.
Note.- If these statements be compared with what we have pointed out concerning the strength of the emotions in this Part up to Prop. xviii., we shall readily see the difference between a man, who is led solely by emotion or opinion, and a man, who is led by reason. The former, whether will or no, performs actions whereof he is utterly ignorant; the latter is his own master and only performs such actions, as he knows are of primary importance in life, and therefore chiefly, desires; wherefore I call the former a slave, and the latter a free man, concerning whose disposition and manner of life it will be well to make a few observations.
Prop. LXVII. A free man thinks of death least of all things; and his wisdom is a meditation not of death but of life.
Proof.- A free man is one who lives under the guidance of reason, who is not led by fear (IV:lxiii.), but who directly desires that which is good (IV:lxiii.Coroll.), in other words (IV:xxiv.), who strives to act, to live, and to preserve his being on the basis of seeking his own true advantage; wherefore such an one thinks of nothing less than of death, but his wisdom is a meditation of life. Q.E.D
Prop. LXVIII. If men were born free, they would, so long as they remained free, form no conception of good and evil.