Ludwig Feuerbach says: A talented writer is recognized by the fact that he assumes talent on the part of the reader also and does not chew up his subject into minute parts like a petty schoolmaster. On the other hand, it seems to me that it is possible to assume too much, and I pursued a schoolmasterly course in this case, because the subject is new to you and still leaves plenty of room for reflection.
I wanted to show by a commonplace example what I mean by insight and understanding and how by means of it the unknown and uncouth becomes known and familiar. True, the understanding in this case was illumined by previous experience, while you are after new knowledge. You want to know how enlightenment arises in order to acquire new insight. Now, all novelty has the dialectic quality of being at the same time something antiquated. New understanding can be acquired only by the help of old understanding. In other words, old and new understanding, which I define here as the faculty of classification, have their existence only in the total interdependence of the universal existence.
You must discard the old prejudice that knowledge can be collected like cents. Although this is well enough, it does not suffice for the purpose of logical thinking. One science belongs to another, and all of them together belong to one class with the entire universe. It will be apparent to you, then, that at the beginning of your young days your knowledge has not sprouted all at once, but has come out of the unknown. And what is true of you, is true of the whole human race. In its cradle it was without intellect. It had, indeed, the germ. But do not beasts, worms, and sensitive plants have that also? In short, the light of perception and understanding is nothing new in the radical sense of the word, but connected with the old and with the world in general, and of the same kind. All our knowledge must be connected and combined into one understanding, one system, one realm, and this is the realm of reality, of truth, of life.
Systematic classification is the task of logic. The first requirement for this purpose is the awakened consciousness of the indivisibility of the universe, of its universal unity. This consciousness is, in other words, at the same time the recognition of the merely formal significance of all scientific classification.
The unity of the universe is true, and is the sole and innate truth. That this sole world truth is full of differences, is just as absolutely different as absolutely the same, does no more contradict a reasonable unity and equality than there is any contradiction in the fact that the various owls have different faces and still the same owl face.
Aristotle divided the sense into five parts, anthropologists the race of man into five races, natural philosophers the space into three dimensions. It is now a question of showing to you that such a division, however true and just, is nevertheless far from being truth and justice, but is merely classification. The fundamental requirement of logic is to designate scientific classifications as that which they are, viz., mental operations. It is the business of the intellect to make classifications. That is its characteristic quality and does not contradict the indivisible truth in the least.
Old wiseacres teach that a reasonable man must not contradict himself, and this is a wise, though very narrow, lesson. Hegel maintains that everything in the world is reasonable, hence the contradictions are also. Under this conservative exterior there is hidden a very revolutionary perception of which the "destructive" minds take advantage in order to flatly contradict the wiseacres and their stable, dead, disordered order which cannot stand any contradiction.
Reason dissolves all contradictions and opposition into harmony by logical classification. "Everything in its own time and place." If it does not wish to be called unreason, reason must rise to the understanding that its opposite is only a formal antagonism. It must know that God and the world, body and soul, life and death, motion and rest, and whatever else the dualists may distinguish, are two and yet one. Then it becomes clear that the conservatives are the real revolutionaries, because by their senseless adherence to the "good old order" they drive the proletariat to desperation, until it upsets that order. On the other hand, the maligned revolutionaries are conservative, because they subordinate themselves to the world's evolutionary process which was, is, and will be eternal.
The red thread winding through all these letters deals with the following points: The instrument of thought is a thing like all other common things, a part or attribute of the universe. It belongs particularly to the general category of being and is an apparatus which produces a detailed picture of human experience by categorical classification or distinction. In order to use this apparatus correctly, one must fully grasp the fact that the world unit is multiform and that all multiformity is a unit.
It is the solution of the riddle of the ancient Eleatic philosophy: How can the one be contained in the many, and the many in one?