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 concede that the expression of opinion is a right of the same kind, it is impossible to contend that on this ground it can claim immunity from interference or that society acts unjustly in regulating it. But the concession is too large. For whereas in the other cases the limitations affect the conduct of every one, restrictions on freedom of opinion affect only the comparatively small number who have any opinions, revolutionary or unconventional, to express. The truth is that no valid argument can be founded on the conception of natural rights, because it involves an untenable theory of the relations between society and its members.
On the other hand, those who have the responsibility of governing a society can argue that it is as incumbent on them to prohibit the circulation of pernicious opinions as to prohibit any anti-social actions. They can argue that a man may do far more harm by propagating anti-social doctrines than by stealing his neighbour's horse or making love to his neighbour's wife. They are responsible for the welfare of the State, and if they are convinced that an opinion is dangerous, by menacing the political, religious, or moral assumptions on which the society is based, it is their duty to protect society against it, as against any other danger.
The true answer to this argument for limiting freedom of thought will appear in due course. It was far from obvious. A long time was needed to arrive at the conclusion that coercion of opinion is a mistake, and only a part of the world is yet convinced. That conclusion, so far as I can judge, is the most important ever reached by men. It was the issue of a continuous struggle between authority and reason—the subject of this volume. The word authority requires some comment.
If you ask somebody how he knows something, he may say, "I have it on good authority," or, "I read it in a book," or, "It is a matter of common knowledge," or, "I learned it at school." Any of these replies means that he has accepted information from others, trusting in their knowledge, without verifying their statements or thinking the matter out for himself. And the greater part of most men's knowledge and beliefs is of this kind, taken without verification from their parents, teachers, acquaintances, books, newspapers. When an English boy learns French, he takes the conjugations and the meanings of the words on the authority of his teacher or his grammar. The fact that in a certain place, marked on the map, there is a populous city called Calcutta, is for most people a fact accepted on authority. So is the existence of Napoleon or Julius Cæsar. Familiar astronomical facts are known only in the same way, except by those who have studied astronomy. It is obvious that every one's knowledge would be very limited indeed, if we were not justified in accepting facts on the authority of others.
But we are justified only under one condition. The facts which we can safely accept must be capable of demonstration or verification. The examples I have given belong to this class. The boy can verify when he goes to France or is able to read a French book that the facts which he took on authority are true. I am confronted every day with evidence which proves to me that, if I took the trouble, I could verify the existence of Calcutta for myself. I cannot convince myself in this way of the existence of Napoleon, but if I have doubts about it, a simple process of reasoning shows me that there are hosts of facts which are incompatible with his non-existence. I have no doubt that the earth is some 93 millions of miles distant from the sun, because all astronomers agree that it has been demonstrated, and their agreement is only explicable on the supposition that this has been demonstrated and that, if I took the trouble to work out the calculation, I should reach the same result.
But all our mental furniture is not of this kind. The thoughts of the average man consist not only of facts open to verification, but also of many beliefs and opinions which he has accepted on authority and cannot verify or prove. Belief in the Trinity depends on the authority of the Church and is clearly of a different order from belief in the existence of Calcutta. We cannot go behind the authority and verify or prove it. If we accept it, we do so because we have such implicit faith in the authority that we credit its assertions though incapable of proof.
The distinction may seem so obvious as to be hardly worth making. But it is important to be quite clear about it. The primitive man who had learned from his elders that there were bears in the hills and likewise evil spirits, soon verified the former statement by seeing a bear, but if he did not happen to meet an evil spirit, it did not occur to him, unless he was a prodigy, that there was a distinction between the two statements; he would rather have argued, if he argued at all, that as his tribesmen were right about the bears they were sure to be right also about the spirits. In the Middle Ages a man who believed on authority that there is a city called Constantinople and that comets are portents signifying divine wrath, would not distinguish the nature of the evidence in the two cases. You may still sometimes hear arguments amounting to this: since I believe in Calcutta on authority, am I not entitled to believe in the Devil on authority?
Now people at all times have been commanded or expected or invited to accept on authority alone—the authority, for instance, of public opinion, or a Church, or a sacred book—doctrines which are not proved or are not capable of proof. Most beliefs about nature and man, which were not founded on scientific observation, have served directly or indirectly religious and social interests, and hence they have been protected by force against the criticisms of persons who have the inconvenient habit of using their reason. Nobody minds if his neighbour disbelieves a demonstrable fact. If a sceptic denies that Napoleon existed, or that water is composed of oxygen and hydrogen, he causes amusement or ridicule. But if he denies doctrines which cannot be demonstrated, such as the existence of a personal God or the immortality of the soul, he incurs serious disapprobation and at one time he might have been put to death. Our mediæval friend would have only been called a fool if he doubted the existence of Constantinople, but if he had questioned the significance of comets he might have got into trouble. It is possible that if he had been so mad as to deny the existence of Jerusalem he would not have escaped with ridicule, for Jerusalem is mentioned in the Bible.
In the Middle Ages a large field was covered by beliefs which authority claimed to impose as true, and reason was warned off the ground. But reason cannot recognize arbitrary prohibitions or barriers, without being untrue to herself. The universe of experience is her province, and as its parts are all linked together and interdependent, it is impossible for her to recognize any territory on which she may not tread, or to surrender any of her rights to an authority whose credentials she has not examined and approved.
The uncompromising assertion by reason of her absolute rights throughout the whole domain of thought is termed rationalism, and the slight stigma which is still attached to the word reflects the bitterness of the struggle between reason and the forces arrayed against her. The term is limited to the field of theology, because it was in that field that the self-assertion of reason was most violently and pertinaciously opposed. In the same way free thought, the refusal of thought to be controlled by any authority but its own, has a definitely theological reference. Throughout the conflict, authority has had great advantages. At any time the people who really care about reason have been a small minority, and probably will be so for a long time to come. Reason's only weapon has been argument. Authority has employed physical and moral violence, legal coercion and social displeasure. Sometimes she has attempted to use the sword of her adversary, thereby wounding herself. Indeed the weakest point in the strategical position