P66: From the guidance of reason we want a greater future good in preference to a lesser present one, and a lesser present evil in preference to a greater future one.

Dem.: If the Mind could have an adequate knowledge of a future thing, it would be affected toward it with the same affect as it is toward a present one (by P62). So insofar as we attend to reason itself, as in this Proposition we suppose ourselves to do, the thing will be the same, whether the greater good or evil is supposed to be future or present. And therefore (by P65), we want the greater future good in preference to the lesser present one, etc., q.e.d.

Cor.: From the guidance of reason, we shall want a lesser present evil which is the cause of a greater future good, and pass over a lesser present good which is the cause of a greater future evil. This Corollary stands to P66 as P65 C does to P65.

Schol.: If these things are compared with those we have shown in this Part up to P18, concerning the powers of the affects, we shall easily see what the difference is between a man who is led only by an affect, or by opinion, and one who is led by reason. For the former, whether he will or no, does those things he is most ignorant of, whereas the latter complies with no one’s wishes but his own, and does only those things he knows to be the most important in life, and therefore desires very greatly. Hence, I call the former a slave, but the latter, a free man.

I wish now to note a few more things concerning the free man’s temperament and manner of living.