My subject, dear Eugene, is the simplest in the world, but it requires thorough treatment for all its full understanding. So every letter is in a way but a repetition of the same argument. "It is remarkable," says Schopenhauer, "that we find the few main theses of pre-socratic philosophy repeated innumerable times. Also in the works of modern thinkers, such as Cartesius, Spinoza, Leibniz, and even Kant, we find that their few main theses are repeated over and over."

Now I ask you to consider what I said in my first letters, viz., that the titles of the principal philosophical works reveal that philosophy is engaged in the study of logic, in the analysis of the intellect and the art of its use. You will then recognize that in the very nature of the subject my presentation of the matter lacks systematization. It has no real beginning and end, because its object, the intellect, is interconnected with the whole universe, which is without beginning and end, which has neither before nor after, neither above nor below.

You may venture that the relation of the intellect to the universe does not concern the intellect especially, but is a universal matter. That would be true.

But it is easy to show that the art of thinking and wisdom of the world are identical. And although the universal interrelation of things is germain to all things and subjects, yet its consideration is a special task of logic which treats all objects of thought summarily.

My subject therefore begins everywhere, even though it is a specialty. Hence I take the liberty to take my departure from any literature which I happen to study. In the present letter, I deal with "logical investigations" of the prominent Professor Trendelenburg. His is a bulky volume, but you need not fear that I shall weary you with its subtleties. As a rule I read only the preface of philosophical works of the second and third order, their introduction and perhaps the first few chapters. Then I am approximately informed as to what I may expect from them further on. One frequently finds statements which, if they do not throw new light on the subject, still bring out in bolder relief some of the accomplishments of historical research in our field. And in order that the son may not trust to the father alone, which might lead to distrust, I connect my argument with some statements of Trendelenburg.

In the preface to the second edition the author complains of the "dull headache" which the Hegelian intoxication has left in Germany and says: "Philosophy will not resume its old power until it becomes consistent, and it will not become consistent until it grows in the same way that all other sciences do. In other words, it must not take a new departure in every brain and then quit, but it must approach its problems historically and develop them. The German prejudice must be abandoned, according to which the philosophy of the future is supposed to look for a new principle. This principle has already been found. It consists in the organic world conception, the fundaments of which are resting in Plato and Aristotle."

The Professor is right, but he overlooks that the philosophers, even of modern times, do not begin "each on his own account," do not have "each his own principle," or if they have, such a "false originality" is but the indifferent attribute of historical development which has handed the object of logic, the true art of thought, from generation to generation in an ever brighter condition.

I repeat this emphatically for pedagogic reasons, because I consider it essential to convince you and the reader that the apparent paradoxes which I state are the objects of discussion since time immemorial. I also wish to stimulate you to a study of the master works of philosophy which show the cheering spectacle, in the persons of the most brilliant specimens of the human mind, of the onward march of this mind from darkness to light.

In order that the wheat contained in this human treasure box may not be concealed by the tares, I am endeavoring to throw light on the outcome of the historical development of philosophy, and for this purpose I continue to discuss the question by taking my departure in this instance from some further statements of Trendelenburg.

"It is a peculiarity of philosophical methods of reasoning to recognize a part in the whole, and it is tacitly assumed that the whole is descended from a thought which determines the parts. On the other hand, it is peculiar to empirical methods of analysis to study the parts without regard to their interrelation, or at best to collect them and put them together, and it is tacitly assumed that every point is something peculiar in itself which must be studied apart from all the rest."

"The aim of all human understanding is always to solve the miracle of divine creation by further creative thought. When this task is undertaken in detail, the detail study forces one on to other things: for things must go backwards toward their dissolution by the same force through which they arose out of the depths."

These sentences state the problem before us. Shall we use the intellect philosophically, or shall we use it empirically? We are striving to understand the parts and the whole, and this is identical with the research after a systematical world philosophy, or with the art of dialectics. Now we must state in the first place that thinking of any kind, whether it be philosophical or empirical, is of the same species, that the same kernel is contained in both forms. Roses are different flowers from carnations, but the flower nature is in both of them. Thus the nature of thought is contained in both philosophical and empirical thinking. The distinction is well enough, but their unity must not be lost sight of.

The philosophers, he says, seek to understand the detail by the whole; the empirical thinkers analyze the details without regard to interrelations. But both methods of research are different specimens of the same genus, and both of them are one-sided when their interconnection is overlooked. The empirical thinker who seeks to understand the details in their isolation, thinks philosophically, when he regards his special research as a contribution to the whole, and the philosopher, who seeks to understand the detail by the whole, thinks empirically when he rightly regards all details as attributes of the whole.

Trendelenburg, then, has expressed his case very obscurely. Both methods of study, if employed one-sidedly, entirely misconceive the art of thinking. The philosophers err when they regard the intellect as the only source of understanding and truth; it is only a part of truth and must be supplemented by all the rest of the world. On the other hand, the empirical thinkers err when they look for understanding and truth exclusively in the outer world, without taking into account the intellectual instrument by the help of which they lift their treasures. In fact, such one-sided philosophers exist only in theory; I mean there are some who imagine that truth could be one-sided. But in practice they all testify, much against their will, to the inevitable interconnection of matter and mind, of inside and outside. In the practical use of the intellect everybody shows that the part operates in the whole, and that the whole is active in its parts.

We know a priori that the universe is a whole. The universal existence can be conceived only as of one kind or nature. The mere thought that there might be something which does not partake of the nature of the universe is no thought, because it is a thought without sense or reason. The whole world is the supreme being, though I grant that we have but a vague conception of it. We have as yet no detailed, true, conception of the universe, but it is gradually acquired in the course of science. Still, our conception will never be perfect because details are infinitesimal and the absolute being is infinite growth.

As to details, we know them more or less accurately and yet not accurately, because even the most minute part of the infinite is infinite. All science has searched in vain for atoms. What our understanding knows, has always been nothing but predicates or attributes of truth, although they are true attributes and are truly understood by us.

I emphasize the inadequacy of all modes of thought and of all understanding in opposition to those who make an idol of science. I emphasize the truth of all perceptions in opposition to those knownothings who claim that truth cannot be understood, but can only be admired and worshipped. Hence it follows for our theory of understanding that intellect and reason and the art of thought are no independent treasure boxes which make any revelations to us. They are theoretical classifications which in practice are operative only in the universal interconnection of things. Understanding, perceiving, judging, distinguishing and concluding, etc., are unable to produce any truths. They can only enlighten and clarify experience by logical classification and distinction. Because man produces works which are preceded by planning, therefore the philosophical mode of research has "assumed that the whole is descended from a thought." But this is an assumption of human origin, which is shown to be without foundation on closer analysis. The plans of our works are copies of natural originals and are "free creations of the mind" only in a limited sense. The artists are well aware of the natural descent of their thoughts and fictions. To regard the world as the outcome of thought is a perverse logic. It is the first condition of rational, proletarian, thought to recognize the intellect and its products as attributes of the world subject.