401. The sphere of procreating and of protecting what is procreated has a like progression from end, through cause, into effect. The end there, is the will or love of procreating. The mediate cause through which and into which the end betakes itself is conjugial love. The progressive series of efficient causes is the loving embrace, the conception and gestation of the embryo or fetus to be procreated, and the effect, this being the procreated infant itself. But although end, cause, and effect progress successively as three, yet, in the love of procreating and inwardly in the several causes and in the effect itself, they make a one. It is only the efficient causes that progress through time, because in nature; the end, that is, the will and love remain ever the same; for in nature, ends progress through times without time, but they cannot come forth and manifest themselves until the effect or use exists and becomes their subject. Prior to this, the love could love only the progression; it could not fix and establish itself.  That there are periods of such progressions is known and also that the preservation of Creation in the state foreseen and provided for, is effected by their means. But the series of the love of infants from its greatest to its least, and so to its terminus where it stops or comes to an end, is a retrograde series because it proceeds according to the decrease of innocence in its subject, and also because of its periods.