s love is, unless it be known what conjugial love is,
needs no demonstration, but only illustration by similitudes: as for
example, who can know what is evil and false, unless he know what is
good and true? and who knows what is unchaste, dishonorable, unbecoming,
and ugly, unless he knows what is chaste, honorable, becoming, and
beautiful? and who can discern the various kinds of insanity, but he
that is wise, or that knows what wisdom is? also, who can rightly
perceive discordant and grating sounds, but he that is well versed in
the doctrine and study of harmonious numbers? in like manner, who can
clearly discern what is the quality of adultery, unless he has first
clearly discerned what is the quality of marriage? and who can make a
just estimate of the filthiness of the pleasures of adulterous love, but
he that has first made a just estimate of the purity of conjugial love?
As I have now completed the treatise ON CONJUGIAL LOVE AND ITS CHASTE
DELIGHTS, I am enabled, from the intelligence I thence acquired, to
describe the pleasures respecting adulterous love.

425. II. ADULTEROUS LOVE IS OPPOSED TO CONJUGIAL LOVE. Every thing in
the universe has its opposite; and opposites, in regard to each other,
are not relatives, but contraries. Relatives are what exist between the
greatest and the least of the same thing; whereas contraries arise from
an opposite in contrariety thereto; and the latter are relatives in
regard to each other, as the former are in their regard one to another;
wherefore also the relations themselves are opposites. That all things
have their opposites, is evident from light, heat, the times of the
world, affections, perceptions, sensations, and several other things.
The opposite of light is darkness; the opposite of heat is cold; of the
times of the world the opposites are day and night, summer and winter;
of affections the opposites are joys and mourning, also gladnesses and
sadnesses; of perceptions the opposites are goods and evils, also truths
and falses; and of sensations the opposites are things delightful and
things undelightful. Hence it may be evidently concluded, that conjugial
love has its opposite; this opposite is adultery, as every one may see,
if he be so disposed, from all the dictates of sound reason. Tell, if
you can, what else is its opposite. It is an additional evidence in
favor of this position, that as sound reason was enabled to see the
truth of it by her own light, therefore s