It is said that ideas are explosive and dangerous. To allow them unfettered freedom is, in fact, to invite disorder. But, to this position, there are at least two final answers. It is impossible to draw a line round dangerous ideas, and any attempt at their definition involves monstrous folly. If views, moreover, which imply disorder are able to disturb the foundations of the state, there is something supremely wrong with the governance of that state. For disorder is not a habit of mankind. We cling so eagerly to our accustomed ways that, as even Burke insisted, popular violence is always the outcome of a deep popular sense of wrong. The common man can only be persuaded to outbreak, granted his general habits, when the government of the taste has lost its hold upon his affections; and that loss is always the reflection of a profound moral cause. We may, indeed, go further and argue that the best index to the quality of a state is the degree in which it is able to permit free criticism of itself. For that implies an alertness to public opinion, a desire to remedy grievance, which enables the state to gain ground in the allegiance of its citizens. Almost always freedom of speech results in a mitigation which renders disorder unnecessary; almost always, also, prohibition of that freedom merely makes the agitation more dangerous because it drives it underground. Rousseau was infinitely more dangerous as a persecuted wanderer, because infinitely more interesting and, therefore, infinitely more persuasive, than he would have been when unfettered in Paris. Lenin did far more harm to Russia as an exile in Switzerland than he could ever have accomplished as an opposition leader in the Duma. The right freely to publish the written word is, in fact, the supreme Katharsis of discontent. Governments that are wise can always learn more from the criticism of their opponents than they can hope to discover in the eulogies of their friends. When they stifle that criticism, they prepare the way for their own destruction. There is, I think, an undeniable difference between freedom of written and freedom of spoken, expression. In the one case, a man attempts conviction by individual persuasion; he seeks, by argument which he believes to be rational, to move the mind of those who read what he has written. To speak at a meeting raises different problems. No one with experience of a great crowd under the sway of a skilled orator can doubt his power deliberately to create disorder if he so desires. A speaker at Trafalgar Square, for instance, who urged a vast meeting of angry unemployed to march on Downing Street, could do so with a fair assurance that they would obey his behest. I do not think a government can be left to the not always tender mercies of an orator with a grievance to exploit. The state, clearly, has the right to protection against the kind of public utterance which is bound to result in disorder.