A man not trained in logical thinking is handicapped by the absence of a monistic method of thought. Monistic is synonymous with systematic, logical, or uniform.

If we call a cream puff a tidbit and rye bread a food without remembering that every food is a tidbit and every tidbit food, and if we ignore the fact that both of them, in spite of their difference, belong to the same category and are, therefore, related, then we lack logic. And logic is lacking whenever the fact is ignored that all things without exception: substances, forces, or qualities of the world, are chips of the same block, finite parts of the infinite, which is the only truth and reality.

That insects, fishes, birds, and mammals form one and the same animal kingdom, is an old story which has long been patched up by the logical instinct. Darwin did not only enrich the natural sciences, but also perform an invaluable service for logic. In proving how amphibia developed into birds, he bored a hole into the hitherto fixed order of classification. He brought motion, life, spirit into the zoological swamp.

In case you should not be familiar enough with Darwin's work to understand my allusions, I will enter a little more deeply into the matter in a few sentences. The zoologists knew well enough that all species of animals belonged to the animal kingdom; but this classification was a mechanical affair. Now the "Origin of Species," which demonstrates that the zoological classification is not constant but variable, which outlines the actual transition from one species of animals to another, reveals at the same time that this alignment of all animal species in one kingdom is not only a logical mechanism, but also a fact of actual existence. This classification of all animals from the minutest to the most gigantic in one kingdom appeared before the time of Darwin as an order which had been accomplished by thought alone, while after him it was known as an order of nature.

What the zoologists did to the animal kingdom, must be done by the logician to existence in general, to the cosmos. It must be shown that the whole world, all forms of its existence, including the spirit, are logically or monistically connected, related, welded together.

A certain narrow materialism thinks that everything is done and said when the inter-connection between thought and brain is pointed out. A good many things may still be discovered by the help of the dissecting knife, microscope, and experiment; but this does not make the function of logic superfluous. True, thought and brain are connected, just as intimately as the brain is related to the blood, the blood with oxygen, etc.; but moreover thought is connected quite as intimately with all other things as all physical objects are.

That the apple is not alone dependent on the stem which attaches it to the tree, but also on sunshine and rain, that these things are not one-sidedly but universally connected, this is what logic wants to teach you particularly in regard to the spirit, the thought.

If a traveler in Africa had to report a new animal species, he would not make special mention of the fact of its existence, because that is obvious. And though he were to relate things about the most abnormal existence, we should still know that this abnormality is only a deviation in degree which does not overstep the bounds of existence in general. But the human intellect is a greater novelty than the most wonderful animal species of the interior of Africa.

You know my sharpwitted friend EnglÄnder. When I told him that I was writing articles on the human mind, he advised me not to bother my head about it. He said that this was a subject no man knew anything about. And when the learned Mr. Hinze, whom you also know, wanted to prove the inevitability of religious faith and the inadequacy of all science, he always asked the pathetic question: What is consciousness? And he used to take on an expression, as if he had presented a book with seven seals. Now I don't want to class the professors of logic with such men. But it is a fact that the great multitude, among them many scientists, are quite unfamiliar with the truth that the existence of the blue sky and of the green trees is a uniform part of the same generality with the existence of our intellect.

For this reason it is necessary to prove that the intellect exists in the same way that all other things do. For it is denied and misunderstood, not only by those who regard the spirit as a being of a transcendental nature, but also by those who admit the existence of the true contents of an ideological concept, but not of thought itself. In short, the matter is so obscure that I feel sure that you will likewise be as yet in doubt whether there are not two kinds of ideological concepts, one of them real, the other unreal.

For two thousand years logic has proclaimed the sentence that thought is a form to be filled with real contents. True thought "must coincide with reality." It is true that there is a germ of sense in this statement, but it is misunderstood. The central point of logic is overlooked. Every thought must not only have a real content, but it is also necessary, in order to distinguish true thoughts or perceptions from untrue, to realize that thought is always and everywhere a part of reality and truth, even when it contains the most singular imaginations and errors.

Just as the domestic cat and the panther are different species of cats and yet belong to the same genus of cats, so true and false thoughts, in spite of all their differences, are of the same genus. For truth is so great that it comprises absolutely everything. Truth, reality, the world, the all, the infinite and the absolute are synonymous expressions. A clear conception of truth is indispensable for the understanding of logic. And in the last analysis it is simply using different words for the same thing, when I base the quintessence of logic, its fulcrum, cardinal, salient, or distinctive point on the spirit intimately united to nature or on the concept of a uniform world, truth, or reality. I cannot give you a clearer view of truth than by quoting at this place the famous words of Lessing: "If God were to offer me the ever active striving for truth in his left hand and truth in his right hand, I should grasp his left and say: Father, keep truth, it is for you alone." This statement is somewhat highflown and mystical, and Lessing was no doubt somewhat embarrassed by mystical thinking. Still there is a sober truth in these words, which is quite clear and to the point.

"Truth itself" is the universe, the infinite and inexhaustible. Every part of it is a finite part of the infinite and is, therefore, finite and infinite, perishable and imperishable at the same time. Every part is a separate part and connected inseparably with the whole. The human mind, among others, is such a part.

The universal existence, or truth, is the inexhaustible object of the human mind. The fact that in the study of logic the human mind has itself for an object must be explained to the student by pointing out that in this case the subject and the object are both things like all other things, in other words, are a part of truth, a part of natural existence.

"Truth itself" cannot be wholly conceived by the human brain, but in parts. For this reason we possess only the ever active striving for truth; for this reason, furthermore, the conception or knowledge can never be completely identical with reality, but can be only a part of it.

Now permit me to say a few words which do not sound as would those spoken on the throne of logic, but which are expressed in popular language. If you conceive some real object, whether a church steeple or a thimble, then this object exists twice, viz., in reality and in conception. On the other hand, a certain creation of imagination has only a simple fantastical existence. Such a popular way of thinking is undoubtedly correct. It is incorrect only when the fact is universally ignored that all modes of existence belong to the same genus, the same as a domestic cat and a panther, so that the existence of a thing in our brains, and outside of them in the heavens, on earth, and in all places has a logical meaning only when it is the same existence in spite of all multiplicity. An existence not partaking of the general nature of all existence would be an illogical, nonsensical, thing.

Now, I think you will have no difficulty in understanding me when I say that a church steeple in imagination and the same church steeple in reality are not two church steeples, but that imagination and reality are forms of the same existence.

Ancient logic ordered a medal and had stamped on its face: The thought must be identical with the reality. We now stamp on its reverse side: (1) The thought is itself a part of reality and (2) the reality outside of thought is too voluminous and cannot enter thought even with its smallest particle. What good, under these circumstances, is the old inscription, especially since it does not teach us at all how the identity between thought and its real object is to be attained, known, or measured?

If you, my dear Eugene, should become confused by these statements instead of enlightened, you should have patience and consider that a thing which is to be illuminated by logic must, of course, be first obscure. I believe that I have served you in some way by simply raising a doubt in your mind as to the soundness of the popular way of speaking and if I thus have convinced you of the confusion and inadequacy of the plausible idea of the identity of thought and reality.

True, a thought must agree with its object just as a portrait should. But what good will it do a painter to have his special attention called to this fact?

Have you ever seen a portrait or a copy that did not agree in some respect with the original? I am convinced that this has never been your experience any more than a portrait which was a complete likeness of its object. Your experience will be sufficiently cultivated to know that it can always be a question only of a more or less. I would seriously recommend to you to reflect on the relativeness of all equality, similarity, and identity. By far the greater part of humanity is in this respect barbarously thoughtless. It is very difficult to grasp for the logically untrained brain that two drops of water or twins are only relatively alike or unlike, just as are man and woman, negro and white man, and that all existence is just as alike as it is unlike.

It is with the thinker as it is with the painter. They both search for a likeness of reality and truth. In painting as in understanding there are excellent pictures and bad ones. In this respect one may make a distinction between true and false thoughts, but you must also know that even the unsuccessful portrait has some likeness, and that even the most accurate likeness is yet far from being in perfect harmony and identical with its object.

Reality, truth, universal nature, stands in the pulpit and preaches: "I am the Lord, thy God. Thou shalt not make any graven image to worship it." You must have a far too sublime conception of truth to entertain the idea that any painter or thinker might encompass it fully within the limit of a picture, no matter how good a likeness it may be.

Now, that we have recognized the human mind as a part of actual reality and truth, we see at the same time that undivided reality, the sum of all that is, represents absolute truth which comprises everything. In their capacity of parts of the universe, true and false thoughts, good and bad men, heaven and hell, and all other things, are all pieces of the same cloth, bombs of the same caliber.