When, on the occasion of its second edition in 1914, I enlarged my book, World and Life Conceptions of the Nineteenth Century, the result was the present volume, The Riddles of Philosophy. In this book I intend to show those elements of world conceptions that appear historically and that move the contemporary observer of these riddles to experiences of greater depth of consciousness as he encounters the feelings with which they were experienced by the thinkers of the past. Such a deepening of the feelings is of profound satisfaction to one who is engaged in a philosophical struggle. What he in his own mind is striving for is strengthened through the fact that he sees how this endeavor took shape in earlier thinkers on whom life bestowed viewpoints that may be close to, or far from, his own. In this way I intend in this book to serve those who need a presentation of the development of philosophy as a supplement to their own paths of thought. Such a supplement will be valuable to anyone who, in his own mode of thinking, wishes to feel himself at one with the intellectual work of mankind, and who would like to see that the work of his own thoughts has its roots in a universal need of the human soul. He can grasp this when he allows the essential elements of the historical world conceptions to unfold before his eye.
For many observers, however, such a display has a depressive effect. It causes doubt to invade their minds. They see thinkers of the past contradicting their predecessors and contradicted by their successors in turn. It is the intention in my account of this process to show how this depressing aspect is extinguished by another element. Let us consider two thinkers. At first glance the contradiction of their thoughts strikes us as painful. We now take these thoughts under a closer inspection. We find that both thinkers direct their attention to entirely different realms of the world. Suppose one thinker had developed in himself the frame of mind that concentrates on the mode in which thoughts unfold in the inner weaving of the soul. For him it becomes a riddle how these inward soul processes can become decisive in a cognition concerning the nature of the external world. This point of departure will lend a special color to all his thinking. He will speak in a vigorous manner of the creative activity of the life of thought. Thus, everything he says will be colored by idealism. A second thinker turns his attention toward the processes accessible to external sense perception. The thought processes through which he holds these external events in cognitive perception do not themselves in their specific energy enter the field of his awareness. He will give a turn to the riddles of the universe that will place them in a thought environment in which the ground of the world itself will appear in a form that bears semblance to the world of the senses.
If one approaches the historical genesis of the conflicting world views with presuppositions that result from such a thought orientation, one can overcome the deadening effect these world perspectives have on each other and raise the point of view to a level from which they appear in mutual support.
Hegel and Haeckel, considered side by side, will at first sight present the most perfect contradiction. Penetrating into Hegel's philosophy, one can go along with him on the path to which a man who lives entirely in thoughts is bound. He feels the thought element as something that enables him to comprehend his own being as real. Confronted with nature, the question arises in him of the relation in which it stands toward the world of thought. It will be possible to follow his turn of mind if one can feel what is relatively justified and fruitful in such a mental disposition. If one can enter into Haeckel's thoughts, one can again follow him part of the way. Haeckel can only see what the senses grasp and how it changes. What is and changes in this way he can acknowledge as his reality, and he is only satisfied when he is able to comprise the entire human being, including his thought activity, under this concept of being and transformation. Now let Haeckel look on Hegel as a person who spins airy meaningless concepts without regard to reality. Grant that Hegel, could he have lived to know Haeckel, would have seen in him a person who was completely blind to true reality. Thus, whoever is able to enter into both modes of thinking will find in Hegel's philosophy the possibility to strengthen his power of spontaneous, active thinking. In Haeckel's mode of thought he will find the possibility to become aware of relations between distant formations of nature that tend to raise significant questions in the mind of man. Placed side by side and measured against one another in this fashion, Hegel and Haeckel will no longer lead us into oppressive skepticism but will enable us to recognize how the striving shoots and sprouts of life are sent out from very different corners of the universe.
Such are the grounds in which the method of my presentation has its roots. I do not mean to conceal the contradictions in the history of philosophy, but I intend to show what remains valid in spite of the contradictions.
That Hegel and Haeckel are treated in this book to reveal what is positive and not negative in both of them can, in my opinion, be criticized as erroneous only by somebody who is incapable of seeing how fruitful such a treatment of the positive is.
Let me add just a few more words about something that does not refer to the content of the book but is nevertheless connected with it. This book belongs to those of my works referred to by persons who claim to find contradictions in the course of my philosophical development. In spite of the fact that I know such reproaches are mostly not motivated by a will to search for truth, I will nevertheless answer them briefly.
Such critics maintain that the chapter on Haeckel gives the impression of having been written by an orthodox follower of Haeckel. Whoever reads in the same book what is said about Hegel will find it difficult to uphold this statement. Superficially considered, it might, however, seem as if a person who wrote about Haeckel as I did in this book had gone through a complete transformation of spirit when he later published books like Knowledge of the Higher World and Its Attainment, An Outline of Occult Science, etc.
But the question is only seen in the right light if one remembers that my later works, which seem to contradict my earlier ones, are based on a spiritual intuitive insight into the spiritual world. Whoever intends to acquire or preserve for himself an intuition of this kind must develop the ability to suppress his own sympathies and antipathies and to surrender with perfect objectivity to the subject of his contemplation. He must really, in presenting Haeckel's mode of thinking, be capable of being completely absorbed by it. It is precisely from this power to surrender to the object that he derives spiritual intuition. My method of presentation of the various world conceptions has its origin in my orientation toward a spiritual intuition. It would not be necessary to have actually entered into the materialistic mode of thinking merely to theorize about the spirit. For that purpose it is sufficient simply to show all justifiable reasons against materialism and to present this mode of thought by revealing its unjustified aspects. But to effect spiritual intuition one cannot proceed in this manner. One must be capable of thinking idealistically with the idealist and materialistically with the materialist. For only thus will the faculty of the soul be awakened that can become active in spiritual' intuition.
Against this, the objections might be raised that in such a treatment the content of the book would lose its unity. I am not of that opinion. An historical account will become the more faithful the more the phenomena are allowed to speak for themselves. It cannot be the task of an historical presentation to fight materialism or to distort it into a caricature, for within its limits it is justified. It is right to represent materialistically those processes of the world that have a material cause. We only go astray when we do not arrive at the insight that comes when, in pursuing the material processes, we are finally led to the conception of the spirit. To maintain that the brain is not a necessary condition of our thinking insofar as it is related to sense perception is an error. It is also an error to assume that the spirit is not the creator of the brain through which it reveals itself in the physical world through the production and formation of thought.