[11] strongly, must have made change slow in communities which progressed, and hindered some communities from progressing at all. But they have continued to operate more or less throughout history, obstructing knowledge and progress. We can observe them at work to-day even in the most advanced societies, where they have no longer the power to arrest development or repress the publication of revolutionary opinions. We still meet people who consider a new idea an annoyance and probably a danger. Of those to whom socialism is repugnant, how many are there who have never examined the arguments for and against it, but turn away in disgust simply because the notion disturbs their mental universe and implies a drastic criticism on the order of things to which they are accustomed? And how many are there who would refuse to consider any proposals for altering our imperfect matrimonial institutions, because such an idea offends a mass of prejudice associated with religious sanctions? They may be right or not, but if they are, it is not their fault. They are actuated by the same motives which were a bar to progress in primitive societies. The existence of people of this mentality, reared in an atmosphere of freedom, side by side with others who are always looking out for new ideas and [12] regretting that there are not more about, enables us to realize how, when public opinion was formed by the views of such men, thought was fettered and the impediments to knowledge enormous. Although the liberty to publish one’s opinions on any subject without regard to authority or the prejudices of one’s neighbours is now a well- established principle, I imagine that only the minority of those who would be ready to fight to the death rather than surrender it could defend it on rational grounds. We are apt to take for granted that freedom of speech is a natural and inalienable birthright of man, and perhaps to think that this is a sufficient answer to all that can be said on the other side. But it is difficult to see how such a right can be established. If a man has any “natural rights,” the right to preserve his life and the right to reproduce his kind are certainly such. Yet human societies impose upon their members restrictions in the exercise of both these rights. A starving man is prohibited from taking food which belongs to somebody else. Promiscuous reproduction is restricted by various laws or customs. It is admitted that society is justified in restricting these elementary rights, because without such restrictions an ordered society could not exist. If then we