But it is quite another matter when the attempt is made to regulate such an institution as marriage by law.  In the first place we do not yet know enough about the principles of heredity and the transmissibility of pathological states to enable us to formulate sound legislative proposals on this basis.  Even so comparatively simple a matter as the relationship of tuberculosis to heredity can scarcely be said to be a matter of common agreement, even if it can yet be claimed that we possess adequate material on which to attain a common agreement.  Supposing, moreover, that our knowledge on all these questions were far more advanced than it is, we still should not have attained a position in which we could lay down general propositions regarding the desirability or the undesirability of certain classes of persons procreating.  The question is necessarily an individual question, and it can only be decided when all the circumstances of the individual case have been fairly passed in review.

The objection to any legislative and compulsory regulation of the right to marry is, however, much more fundamental than the consideration that our knowledge is at present inadequate.  It lies in the extraordinary confusion, in the minds of those who advocate such legislation, between legal marriage and procreation.  The persons who fall into such confusion have not yet learnt the alphabet of the subject they presume to dictate about, and are no more competent to legislate than a child who cannot tell A from B is competent to read.

Marriage, in so far as it is the partnership for mutual help and consolation of two people who in such partnership are free, if they please, to exercise sexual union, is an elementary right of every person who is able to reason, who is guilty of no fraud or concealment, and who is not likely to injure the partner selected, for in that case society is entitled to interfere by virtue of its duty to protect its members.  But the right to marry, thus understood, in no way involves the right to procreate.  For while marriage per se only affects the two individuals concerned, and in no way affects the State, procreation, on the other hand, primarily affects the community which is ultimately made up of procreated persons, and only secondarily affects the two individuals who are the instruments of procreation.  So that just as the individual couple has the first right in the question of marriage, the State has the first right in the question of procreation.  The State is just as incompetent to lay down the law about marriage as the individual is to lay down the law about procreation.

That, however, is only one-half of the folly committed by those who would select the candidates for matrimony by statute.  Let us suppose—­as is not indeed easy to suppose—­that a community will meekly accept the abstract prohibitions of the statute book and quietly go home again when the registrar of marriages informs them that they are shut out from legal matrimony by the new table of prohibited degrees.  An explicit prohibition to procreate within marriage is an implicit permission to procreate outside marriage.  Thus the undesirable procreation, instead of being carried out under the least dangerous conditions, is carried out under the most dangerous conditions, and the net result to the community is not a gain but a loss.