21. “But reason, enabling us to conceive the end and dissolution of the body, and liberating us from the fears relative to eternity, procures for us all the happiness of which life is capable, so completely that we have no further occasion to include eternity in our desires. In this disposition of mind, man is happy even when his troubles engage him to quit life; and to die thus, is for him only to interrupt a life of happiness.
22. “He who is acquainted with the limits of life knows, that that which removes the pain which arises from want, and which makes the whole of life perfect, is easily procurable; so that he has no need of those things which can only be attained with trouble.
23. “But as to the subsisting end, we ought to consider it with all the clearness and evidence which we refer to whatever we think and believe; otherwise, all things will be full of confusion and uncertainty of judgment.
24. “If you resist all the senses, you will not even have anything left to which you can refer, or by which you may be able to judge of the falsehood of the senses which you condemn.
25. “If you simply discard one sense, and do not distinguish between the different elements of the judgment, so as to know on the one hand, the induction which goes beyond the actual sensation, or, on the other, the actual and immediate notion; the affections, and all the conceptions of the mind which lean directly on the sensible representation, you will be imputing trouble into the other sense, and destroying in that quarter every species of criterion.
26. “If you allow equal authority to the ideas, which, being only inductive, require to be verified, and to those which bear about them an immediate certainty, you will not escape error; for you will be confounding doubtful opinions with those which are not doubtful, and true judgments with those of a different character.
27. “If, on every occasion, we do not refer every one of our actions to the chief end of nature, if we turn aside from that to seek or avoid some other object, there will be a want of agreement between our words and our actions.
28. “Of all the things which wisdom provides for the happiness of the whole life, by far the most important is the acquisition of friendship.
29. “The same opinion encourages man to trust that no evil will be everlasting, or even of long duration; as it sees that, in the space of life allotted to us, the protection of friendship is most sure and trustworthy.
30. “Of the desires, some are natural and necessary, some natural, but not necessary, and some are neither natural nor necessary, but owe their existence to vain opinions.”