With this as a text one could set up an inquisition. Yet it occurs in the noblest plea for liberty that exists in the English language. The critical point in Milton’s thought is revealed by the word “indifferences.” The area of opinion which he wished to free comprised the “neighboring differences” of certain Protestant sects, and only these where they were truly ineffective in manners and morals. Milton, in short, had come to the conclusion that certain conflicts of doctrine were sufficiently insignificant to be tolerated. The conclusion depended far less upon his notion of the value of liberty than upon his conception of God and human nature and the England of his time. He urged indifference to things that were becoming indifferent. If we substitute the word indifference for the word liberty, we shall come much closer to the real intention that lies behind the classic argument. Liberty is to be permitted where differences are of no great moment. It is this definition which has generally guided practice. In times when men feel themselves secure, heresy is cultivated as the spice of life. During a war liberty disappears as the community feels itself menaced. When revolution seems to be contagious, heresy-hunting is a respectable occupation. In other words, when men are not afraid, they are not afraid of ideas; when they are much afraid, they are afraid of anything that seems, or can even be made to appear, seditious. That is why nine-tenths of the effort to live and let live consists in proving that the thing we wish to have tolerated is really a matter of indifference. In Mill this truth reveals itself still more clearly. Though his argument is surer and completer than Milton’s, the qualification is also surer and completer. Such being the reasons which make it imperative that human beings should be free to form opinions, and to express their opinions without reserve; and such the baneful consequences to the intellectual and through that to the moral nature of man, unless this liberty is either conceded or asserted in spite of prohibition, let us next examine whether the same reasons do not require that men should be free to act upon their opinions, to carry these out in their lives, without hindrance, either moral or physical, from their fellow men, so long as it is at their own risk and peril. _This last proviso is of course indispensable._ No one pretends that actions should be as free as opinions. On the contrary, _even opinions lose their immunity_ when the circumstances in which they are expressed are such as to constitute their expression a positive instigation to some mischievous act.