odern marriage in Pollock and Maitland,
_History of English Law_, vol. ii.

It is necessary to make allowance for variations, thereby shunning the
extreme theorists who insist on moulding all facts to their theories, but
we may conclude that--as the approximately equal number of the sexes
indicates--in the human species, as among many of the higher animals, a
more or less permanent monogamy has on the whole tended to prevail. That
is a fact of great significance in its implications. For we have to
realize that we are here in the presence of a natural fact. Sexual
relationships, in human as in animal societies, follow a natural law,
oscillating on each side of the norm, and there is no place for the theory
that that law was imposed artificially. If all artificial "laws" could be
abolished the natural order of the sexual relationships would continue to
subsist substantially as at present. Virtue, said Cicero, is but Nature
carried out to the utmost. Or, as Holbach put it, arguing that our
institutions tend whither Nature tends, "art is only Nature acting by the
help of the instruments she has herself made." Shakespeare had already
seen much the same truth when he said that the art which adds to Nature
"is an art that Nature makes." Law and religion have buttressed monogamy;
it is not based on them but on the needs and customs of mankind, and these
constitute its completely adequate sanctions.[313] Or, as Cope put it,
marriage is not the creation of law but the law is its creation.[314]
Crawley, again, throughout his study of primitive sex relationships,
emphasizes the fact that our formal marriage system is not, as so many
religious and moral writers once supposed, a forcible repression of
natural impulses, but merely the rigid crystallization of those natural
impulses, which in a more fluid form have been in human nature from the
first. Our conventional forms, we must believe, have not introduced any
elements of value, while in some respects they have been mischievous.

It is necessary to bear in mind that the conclusion that
monogamic marriage is natural, and represents an order which is
in harmony with the instincts of the majority of people, by no
means involves agreement with the details of any particular legal
system of monogamy. Monogamic marriage is a natural biological
fact, alike in many animals and in man. But no system of legal
regulation is a natural biological fact. When a hig