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.
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.
Learned men, in the study and appreciation of the material world, separate sciences absolutely, and, considering each apart from its practical application, occupy themselves in their scientific investigations only with the pure theory. This I understand and admit; for such a course does not endanger the security of society or the results of their own labours. { 194} Their ignorance and their errors have no doubt grave inconveniences; the facts and the forces of the material world are either misconceived or not turned sufficiently to account; man and human society do not reap all the advantages which the profound and exact knowledge of the truth might, in this respect, procure them. Such ill, although real, is of a negative description, a good, it may be, missed or postponed; but no general disturbance results in that material world upon which naturalists or chemists concentrate their labours; the world will not have to undergo the effect, nor to pay the penalty, of their ignorance or of their errors. The intellectual and moral world, on the contrary, runs a greater risk, and imposes upon its teachers severer duties; no doubt these study it as freely, and make truth, too, their object; but science does not here escape the weight of its own conclusions; it is a power as formidable in its abuse as it is in itself sublime; it may carry into the world to which it addresses itself trouble instead of order, incendiarism instead of light. If practical application is not here the object of science, it is still its necessary and appropriate proof; in facts as in a mirror are reflected the truth or the error, the good or the ill, of human opinions.