development of intellect in the race.

There are as yet no facts to prove that such weakening has taken or is
taking place, nor are there facts to prove that population has in any
way suffered from this cause.

If such a law obtained, and resulted in a diminished birth-rate, the
future of the race would be the gloomiest possible. An inexorable law
would determine that there could be no mental evolution, for the best of
the race would cease to propagate their kind. All who would arrive at
this standard of mental growth would become barren. And against this
there could be no remedy.

One of the main contentions of this work is that the best have to a
large extent ceased to propagate their kind, but it is not maintained
that this is the result of a biological law, over which there is no
control. It can be safely claimed that to Malthus's three checks to
population--vice, misery, and moral restraint, the demographic phenomena
of a century have added no other. The third check, however, moral
restraint, must be held to include all restraint voluntarily placed by
men and women on the free and natural exercise of their powers of
procreation.

Malthus used the term "moral" in this connection, not so much in
relation to the _motive_ for the restraint, but in relation to the
result, viz., the limitation of the family. The "moral restraint" of
Malthus meant to him, restraint from marriage only, chiefly because of
the inability to support a family. It implied marriage delayed until
there was reasonable hope that the normal family, four in number, could
be comfortably supported, continence in the mean time being assumed.