It is boring and difficult to convince people, and after all, not necessary. It would be much better if every individual kept his own opinions. Unfortunately, it cannot be. Whether you like it or not, you have to admit the law of gravitation. Some people find it necessary to admit the origin of man from the monkey. In the empirical realm, however humiliating it may be, there are certain real, binding, universal truths against which no rebellion will avail. With what pleasure would we declare to a representative of science that fire does not burn, that rattlesnakes are not poisonous, that a fall from a high tower is perfectly agreeable, etc., etc., supposing he were obliged to prove to us the contrary. Unluckily the scientific person is free from the burden of proof: nature proves, and thoroughly. If nature, like metaphysics, set out to compel us through syllogisms or sermons to believe in her, how little she would get out of us. She is much more sagacious. Morality and logic she has left to Hegel and Spinoza, for herself she has taken a cudgel. Now then, try to argue against _this_! You will give in against your will. The cleverest of all the metaphysicians, Catholic inquisitors, imitated nature. They rarely tried the word, and trusted to the fire of faggots rather than of the heart. Had they only had more power, it would not be possible to find two people in the whole world disbelieving in the infallibility of the Pope. Metaphysical ideas, dreamily expecting to conquer the world by reasoned exposition, will never attain dominion. If they are bent on success, let them try more effective methods of convincing. 35