LET US RECAPITULATE the results arrived at in the previous chapters. The world confronts man as a multiplicity, as a sum of separate entities. Man himself is one of these separate entities, a being among other beings. This aspect of the world we characterized simply as that which is given, and inasmuch as we do not evolve it by conscious activity, but find it present, we called it perception. Within the world of perceptions we perceive ourself. This self-perception would remain merely one among the many other perceptions, did not something arise from the midst of this self-perception which proves capable of connecting perceptions in general and therefore also the sum of all other perceptions with that of ourself. This something which emerges is no longer mere perception, neither is it, like perceptions, simply given. It is brought about by our activity. To begin with, it appears united with what we perceive as ourself. But in accordance with its inner significance it reaches out beyond the self. It bestows on the separate perceptions ideal definitions, and these relate themselves to one another and stem from a unity. What is attained by self-perception, it defines ideally in the same way as it defines all other perceptions, placing this as subject, or “I,” over against the objects. This something is thinking, and the ideal definitions are the concepts and ideas. Thinking, therefore, first manifests itself in the perception of the self, but it is not merely subjective, for the self characterizes itself as subject only with the help of thinking. This relationship to oneself by means of thoughts is a life-definition of our personality. Through it we lead a purely ideal existence. Through it we feel ourselves to be thinking beings. This life-definition would remain a purely conceptual (logical) one if no other definitions of our self were added to it. We should then be beings whose life would be exhausted in establishing purely ideal relations between perceptions themselves, and between them and ourself. If we call the establishing of such a thought connection, an act of cognition, and the resulting condition of our self knowledge, then according to the above mentioned presupposition, we should have to consider ourselves as beings who merely cognize or know.
However, the presupposition does not correspond to the facts. We relate perceptions to ourselves not merely ideally, through concepts, but also, as we have seen, through feeling. Therefore we are not beings with a merely conceptual life-content. The naive realist even sees in the life of feeling a more genuine life of the personality than in the purely ideal element of knowledge. And from his standpoint he is right in interpreting the matter in this way. For feeling on the subjective side to begin with, is exactly the same as perception on the objective side. From the basic principle of naive realism, that everything that can be perceived is real, it follows that feeling is the guarantee of the reality of one's own personality. Monism, however, as understood here, must confer upon feeling the same supplement that it considers necessary for all perceptions if these are to be present as a complete reality. For monism, feeling is an incomplete reality which, in the form it is first given to us, does not as yet contain its second factor, the concept or idea. This is why in actual life, feelings, like perceptions, appear before cognition has occurred. At first we have merely a feeling of existence, and it is only in the course of gradual development that we reach the point where the concept of our self dawns within the dim feeling of our existence. But what for us appears only later is fundamentally and indivisibly bound up with feeling. This fact leads the naive man to the belief that in feeling, existence is present directly, in knowledge only indirectly. Therefore the development of the feeling-life appears to him more important than anything else. He will believe that he has grasped the connection of things only when he has felt it. He attempts to make feelings rather than knowing the means of cognition. But as feeling is something quite individual, something equivalent to perception, a philosopher of feeling makes into the universal principle, a principle which has significance only within his personality. He tries to permeate the whole world with his own self. What the monist, in the sense we have described, strives to grasp by means of concepts, the philosopher of feeling tries to attain by means of feeling, and considers this relationship with objects to be the one that is most direct.
The view just characterized, the philosophy of feeling, is often called mysticism. The error in mysticism based on feeling alone is that the mystic wants to experience  in feeling what should be attained as knowledge; he wants to develop something which is individual, into something universal.
Feeling is purely individual, it is the relation of the external world to our subject, insofar as this relation comes to expression in merely subjective experience.
There is yet another expression of the human personality. The I, through its thinking, lives within the universal life of the world; through thinking the “I” relates purely ideally (conceptually) the perception to itself, and itself to the perception. In feeling, it experiences a relation of the object to its own subject. In the will, the opposite is the case. In will, we are again confronted with a perception, namely that of the individual relation of our own self to the object. Everything in the will which is not a purely ideal factor is just as much a merely perceived object as any object in the external world.
Nevertheless, here again the naive realist believes that he has before him something far more real than can be reached by thinking. He sees in the will an element in which he is directly aware of a process, a causation, in contrast to thinking, which must first grasp the process in concepts. What the I brings about by its will represents to such a view, a process which is experienced directly. An adherent of this philosophy believes that in the will he has really got hold of a corner of the universal process. Whereas all other events he can follow only by perceiving them from outside, he believes that in his will he is experiencing a real process quite directly. The form of existence in which the will appears to him within the self becomes for him a direct principle of reality. His own will appears to him as a special case of the universal process, and he therefore considers the latter to be universal will. The will becomes the universal principle just as in mysticism of feeling, feeling becomes the principle of knowledge. This view is a Philosophy of the Will (Thelism).  Here something which can be experienced only individually is made into the constituent factor of the world.
The philosophy of will can be called a science as little as can mysticism of feeling. For both maintain that to permeate things with concepts is insufficient. Both demand, side by side with an ideal-principle of existence, a real principle also. And this with a certain justification. But since for this so-called real principle, perceiving is our only means of comprehension, it follows that mysticism of feeling and philosophy of will are both of the opinion that we have two sources of knowledge: thinking and perceiving, perceiving being mediated through feeling and will as individual experience. According to mysticism of feeling and philosophy of will, what flows from the source of experience [44a] cannot be taken up directly into what flows from the source of thinking; therefore the two forms of knowledge, perceiving and thinking, remain standing side by side without a higher mediation. Besides the ideal principle attainable through knowledge, there is also supposed to exist a real principle which, although it can be experienced cannot be grasped by thinking. In other words: mysticism of feeling and philosophy of will are both forms of naive realism; they both adhere to the principle: What is directly perceived is real. Compared with naive realism in its original form, they are guilty of the further inconsistency of making one definite kind of perceiving (feeling or will) into the one and only means of knowing existence; and this they should not do when they adhere in general to the principle: What is perceived is real. According to this, for cognition, external perceptions should have equal value with inner perceptions of feeling or will.
Philosophy of will becomes metaphysical realism when it considers will also to be present in those spheres of existence where a direct experience of it, as in one's own subject, is not possible. It hypothetically assumes a principle outside the subject, for which subjective experience is the sole criterion of reality. The philosophy of will as a form of metaphysical realism is open to the criticism indicated in the preceding chapter; it has to overcome the contradictory element inherent in every form of metaphysical realism, and acknowledge that the will is a universal world process only insofar as it relates itself ideally to the rest of the world.
Addition to the Revised Version, (1918): The reason it is so difficult to observe and grasp the nature of thinking lies in the fact that its nature all too easily eludes the contemplating soul, as soon as one tries to focus attention on it. What then is left is something lifeless, abstract, the corpse of living thinking. If this abstract alone is considered, then it is easy, by contrast, to be drawn into the “living” element in mysticism of feeling, or into the metaphysics of the will, and to find it strange that anyone should expect to grasp the nature of reality in “mere thought.” But one who really penetrates to the life within thinking will reach the insight that to experience existence merely in feeling or in will cannot in any way be compared with the inner richness, the inwardly at rest yet at the same time alive experience, of the life within thinking, and no longer will he say that the other could be ranked above this. It is just because of this richness, because of this inner fullness of living experience, that its reflection in the ordinary life of soul appears lifeless and abstract. No other human soul-activity is so easily underestimated as thinking. Will and feeling warm the human soul even when experienced only in recollection. Thinking all too easily leaves the soul cold in recollection; the soul-life then appears to have dried out. But this is only the strong shadow cast by its warm luminous reality, which dives down into the phenomena of the world. This diving down is done by a power that flows within the thinking activity itself, the power of spiritual love. The objection should not be made that to see love in active thinking is to transfer into thinking a feeling, namely love. This objection is in truth a confirmation of what is said here. For he who turns toward the living essence of thinking will find in it both feeling and will, and both of these in their deepest reality; whereas for someone who turns away from thinking and instead turns toward “mere” feeling or will, for him these will lose their true reality. One who is willing to experience intuitively in thinking, will also be able to do justice to what is experienced in the realm of feeling and in the element of will, whereas mysticism of feeling and metaphysics of will are incapable of doing justice to the activity of permeating existence with intuitive thinking. They all too easily come to the conclusion that they have found reality, whereas the intuitive thinker produces in abstract thoughts without feeling, and far removed from reality, a shadowy, chilling picture of the world.