Of course, the idea of a leathern lady is only a youthful prank. Still it is calculated to illustrate the dialectic transfusion of all names and things, of all subjects and predicates. It shows indirectly that according to common sense thought, reason has its home only in the brain of man, and that this reason is nevertheless unsound when it does not know and remember that the individual human brain is connected with all brains, and reasons with the whole world, so that only all existence and the entire universe is reasonable in the highest meaning of the word. In order to be able to use your reason in all research and on all objects in a reasonable manner, you must know that the whole world has one nature, even leather and your sister. Apparently there is a wide gulf between these two, and yet in both of them the same forces are active, just as a black horse has the same horse nature as a white horse, so that from this point of view your sister is indeed leathern and leather sisterly. Such statements sound paradoxical enough, yet I insist on making them in this extreme manner in order to fully reveal the absolute oneness of all existence, since it is the indispensable basis of a reasonable understanding of logic. Take one of the questions of the day now agitating the public mind, for a further illustration. Two tendencies are now observed in the most radical political movement of the nations. One of them is called propaganda of the deed. It works in Russia and Ireland with dynamite, powder, and lead. The other recommends the propaganda of the word, of the vote, and of lawful agitation. And the difference between these two is not discussed reasonably with a view to ascertaining for whom, when, where, and why, this or that propaganda is fitting, but every one tries to present his relative truth with the fanatical sectarianism of those who claim absolute truth. But if you have grasped the method of getting at truth, the true method of using your reasoning faculty, you will take sides for one thing today and for another thing tomorrow, because you will understand that all roads are leading toward Rome. And if some of the comrades outvote you occasionally, you will still value these antagonists as friends, and if you combat them, even in a war to the knife, this will still be a relative war, a use of the knife with reason. Our proletarian logic is tolerant, not fanatical. This logic does not want to be reasonable without passion, nor passionate without reason. It does not abolish the difference between friend and foe, between truth and falsehood, between reason and nonsense, but calms the fanaticism which exaggerates those distinctions. Its fundamental maxim is: There is only one absolute, the universe.