The reason why the successive changes of state undergone by both partners after marriage depends on whether their conjugial love links or separates their minds, is that conjugial love is not only varying but different in different couples. It varies in the case of those who love each other inwardly, since in their case it ceases from time to time, though inwardly it constantly retains its warmth. But this love is different in the case of couples who love each other only outwardly, for in their case there are different reasons, the alternation of chill and warmth, for it ceasing from time to time.

[2] The principle behind these differences is that in the one case the body plays the leading part, and its heat spreads around forcing the lower regions of the mind to share it. But in the case of those who love each other inwardly, the mind plays the leading part, and carries the body along to share it. It looks as if love rises from the body to the soul, because the body, as soon as it is ensnared, penetrates into the mind through the eyes, as if through a door; and thus into the thoughts through the faculty of sight, as if through a forecourt, and so immediately into love. But in fact love comes down from the mind and acts upon the lower regions so as to reflect their disposition. A lewd mind therefore acts lewdly, a chaste mind chastely; this imposes its will on the body, but the lewd mind has the body impose its will on it.