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.