You will see that these are not merely academic questions; every one of them has been in the forefront of political discussion this last half-century, and all save the first have been vital themes of decision in the years since the war. Take first the case of an association which, like the Mormon Church, desires to practise modes of conduct different from those pursued by the society as a whole. We have to assume that the members of the association have joined it voluntarily, and continue voluntarily in its membership. We have to assume, further, that they do not desire to force their particular way of life upon others; for some single realm of conduct, like the realm of marriage, they desire that they shall be left free from interference by the organized power of society. I cannot see that we are entitled to interfere with them. We may think them unwise, foolish, muddle-headed, immoral. We know perfectly well that we cannot hope, by the external constraint of law, to abolish all conduct that comes within those terms. I happen to think that it is a gross superstition to leave money to the Roman Catholic Church that masses may be said for the testator’s soul; but I should think it an unwarrantable interference with the relations between that Church and its members if such bequests were forbidden. I see no evidence to suggest that the practice of polygamy is worse, in its nature, than a hundred other practices which organized society either directly permits, or wisely leaves alone, because it knows that rigorous control would be utterly futile. The only way to deal with the ideals of the Mormon Church is to prove their undesirability to their members. On the evidence of history, persecution will not be acceptable as proof; and it is not improbable that the only legal effect of prohibition has been to make furtive and dishonest what was, at first, open and avowed. _Mutatis mutandis_, this seems to me the case with all similar problems of association. If a society of women, enthusiastic for the independence of their sex, formed themselves into an association to propagate and practise the (to them) ideal of children outside the tie of marriage, I should not think the state entitled to interfere with its work. So, too, I should argue, with a principle like birth-control. The state is not entitled to prohibit diffusion of such knowledge, or the practice of it. When it does, it makes the family nothing more than an instrument of fecundity, and destroys the whole character of that right to privacy which is the foundation of harmonious sexual relationship.