natural like the same love with other animals,
because it is a vague love of the sex; but as a man was born to become
spiritual, it becomes afterwards natural-rational, and from
natural-rational spiritual, and lastly spiritual-natural; and in this
case, that love made spiritual flows into and acts upon rational love,
and through this flows into and acts upon sensual love, and lastly
through this flows into and acts upon that love in the body and the
flesh; and as this is its ultimate plane, it acts upon it spiritually,
and at the same time rationally and sensually; and it flows in and acts
thus successively while the man is meditating upon it, but
simultaneously while he is in its ultimate. The reason why fornication
is of the natural man, is, because it proceeds proximately from the
natural love of the sex; and it may become natural-rational, but not
spiritual, because the love of the sex cannot become spiritual, until it
becomes conjugial; and the love of the sex from natural becomes
spiritual, when a man recedes from vague lust, and devotes himself to
one of the sex, to whose soul he unites his own.

448. IV. FORNICATION IS LUST, BUT NOT THE LUST OF ADULTERY. The reasons
why fornication is lust are, 1. Because it proceeds from the natural
man, and in everything which proceeds from the natural man, there is
concupiscence and lust; for the natural man is nothing but an abode and
receptacle of concupiscences and lust, since all the criminal
propensities inherited from the parents reside therein. 2. Because the
fornicator has a vague and promiscuous regard to the sex, and does not
as yet confine his attention to one of the sex; and so long as he is in
this state, he is prompted by lust to do what he does; but in proportion
as he confines his attention to one of the sex, and loves to conjoin his
life with hers, concupiscence becomes a chaste affection, and lust
becomes human love.

449. That the lust of fornication is not the lust of adultery, every one
sees clearly from common perception. What law and what judge imputes a
like criminality to the fornicator as to the adulterer? The reason why
this is seen from common perception is, because fornication is not
opposed to conjugial love as adultery is. In fornication conjugial love
may lie stored up within, as what is spiritual may lie stored up in what
is natural; yea, what is spiritual is also actually disengaged from what
is natural; and when the spiritual is disengaged