This is no privilege of philosophers; neither are they the only ones for whom truth is a law: all men have a right to live under its empire, whether as to facts or ideas. No one, not even those who affect most disdain for theory, would venture to lay down the principle that we should be indifferent whether we are essentially in the right, and that practically there is no difference between truth and error. But by what signs is truth recognisable? Are there no other than the affirmations of that inquisitive spectator, named the human mind? Is it only by language, by reasoning, and by discussion, that the truth of an idea and of a doctrine manifests and proves itself? To such a pretension, if advanced, I hesitate not to reply with a denial, and in doing so, to repeat what I have just said: every doctrine, religious, moral, or political, has to submit to a test,--the practical application. {192} The idea transformed into reality, the thought made the life; these are the most certain signs of an idea being intrinsically true, these, too, are proofs of its reasonable legitimacy, which it is bound to give. There is a radical difference between the material world and the intellectual world. The laws which regulate and maintain order in the material world, are independent of man, of both his thought and his volition. It matters not that he knows these laws, or is ignorant of them; they do not the less exist and govern; man has no power to change, arrest, or suspend their operation; he cannot influence them. Galileo was right to say of the earth, in spite of his judges, "Still it moves;" it would have moved even if Galileo, as well as his judges, had been ignorant of the fact, and the contest between the whirlpool of Descartes and Newton's principle of attraction, was a matter perfectly indifferent to the general system of the world. _There_ man's error is absolutely without effect or influence. {193} In the intellectual and moral world it is otherwise; here man is not only spectator, he is an actor, an actor free or not to act-- to act with effect. He thinks and he wills, and so contributes to the facts which take place in the world; he knows, or is ignorant of, the laws, he respects or violates the laws which preside here, but which do not preside here as laws external to and independent of himself. Man's errors, man's faults, are not here without real and serious consequences; they have the power of sowing evil and of carrying perturbation into the intellectual and moral world, thus delivered up, as the Bible proclaims, to the disputes of men.