greater good, or from the fear of a greater evil; nor does anyone endure an
evil except for the sake of avoiding a greater evil, or gaining a greater
good. (28) That is, everyone will, of two goods, choose that which he thinks
the greatest; and, of two evils, that which he thinks the least. (29) I say
advisedly that which he thinks the greatest or the least, for it does not
necessarily follow that he judges right. (30) This law is so deeply
implanted in the human mind that it ought to be counted among eternal truths
and axioms.

(16:31) As a necessary consequence of the principle just enunciated, no one
can honestly promise to forego the right which he has over all things
[Endnote 26], and in general no one will abide by his promises, unless under
the fear of a greater evil, or the hope of a greater good. (32) An example
will make the matter clearer. (33) Suppose that a robber forces me to
promise that I will give him my goods at his will and pleasure. (34) It is
plain (inasmuch as my natural right is, as I have shown, co-extensive with
my power) that if I can free myself from this robber by stratagem, by
assenting to his demands, I have the natural right to do so, and to pretend
to accept his conditions. (35) Or again, suppose I have genuinely promised
someone that for the space of twenty days I will not taste food or any
nourishment; and suppose I afterwards find that was foolish, and cannot be
kept without very great injury to myself; as I am bound by natural law and
right to choose the least of two evils, I have complete right to break my
compact, and act as if my promise had never been uttered. (36) I say that I
should have perfect natural right to do so, whether I was actuated by true
and evident reason, or whether I was actuated by mere opinion in thinking I
had promised rashly; whether my reasons were true or false, I should be in
fear of a greater evil, which, by the ordinance of nature, I should strive
to avoid by every means in my power.