iogenetic law is expanded in a psychogenetic law.

Only man's emotions have undergone evolution, and therefore have a
history, while those of woman have experienced no change.

Lucka's book will probably not please the advanced feminists, but the
delicate, although perhaps involuntary homage to her sex which is
implied in his theories ought to rouse a feeling of gratification in the
heart of every right-feeling woman. The very limitations and
restrictions which he lays upon her raise and glorify her. For while man
has been the "Odysseus wandering through heaven and hell, passing from
the bestial to the divine to return again and become human, woman has
always been the same, unchangeable and without problems. That which he
has set up to-day as his highest erotic ideal, the blending of sexual
and spiritual love, has been her natural endowment from the beginning.
Never perfect, he falls into error and sin where she cannot err, for her
instinct is Nature herself, and she knows not the meaning of sin."

Schopenhauer's "instinct of philoprogenitiveness" has to-day become an
article of faith with the learned and the unlearned. This _sub-conscious
instinct for the service of the species_ which, in love, is supposed to
rise to consciousness, and whose purpose is the will to produce the best
possible offspring, is conceded by scientists who reject not only
Schopenhauer's metaphysic, but metaphysic in general. Even Nietzsche,
that arch-individualist, has proved by many of his pronouncements, and
most strikingly by his well-known definition of marriage, that he has
not escaped its fascinations. "Schopenhauer ignores all phenomena which
are not in support of his myth," says Lucka, who denies this instinct of
philoprogenitiveness and would substitute for it a "pairing-instinct."
"The experience of others," he argues, "not our own instinct, has taught
us that children _may_, not necessarily _must_, be the result of the
union of the sexes. Into the mediaeval ideal which reached its climax in
metaphysical love, the idea of propagation did not enter. Moreover, the
desire for children is frequently unaccompanied by any sexual desire,
and therefore to manufacture an instinct of philoprogenitiveness is
fantastic metaphysic, and is entirely opposed to intellectual reality.
This was well understood in the long period of antiquity which strictly
separated the sexual impulse and the desire for children."

Lucka distinguishes three great stage