We have established that the elements for the explanation of reality are to be taken from the two spheres of perception and thought. It is due, as we have seen, to our organisation that the full totality of reality, including our own selves as subjects, appears at first as a duality. Knowledge transcends this duality by fusing the two elements of reality, the percept and the concept, into the complete thing. Let us call the manner in which the world presents itself to us, before by means of knowledge it has taken on its true nature, “the world of appearance,” in distinction from the unified whole composed of percept and concept. We can then say, The world is given to us as a duality (Dualism), and knowledge transforms it into a unity (Monism). A philosophy which starts from this basal principle may be called a Monistic philosophy, or Monism. Opposed to this is the theory of two worlds, or Dualism. The latter does not, by any means, assume merely that there are two sides of a single reality, which are kept apart by our organisation, but [110]that there are two worlds totally distinct from one another. It then tries to find in one of these two worlds the principle of explanation for the other.
Dualism rests on a false conception of what we call knowledge. It divides the whole of reality into two spheres, each of which has its own laws, and it leaves these two worlds standing outside one another.
It is from a Dualism such as this that there arises the distinction between the object of perception and the thing-in-itself, which Kant introduced into philosophy, and which, to the present day, we have not succeeded in expelling. According to our interpretation, it is due to the nature of our organisation that a particular object can be given to us only as a percept. Thought transcends this particularity by assigning to each percept its proper place in the world as a whole. As long as we determine the separate parts of the cosmos as percepts, we are simply following, in this sorting out, a law of our subjective constitution. If, however, we regard all percepts, taken together, merely as one part, and contrast with this a second part, viz., the things-in-themselves, then our philosophy is building castles-in-the-air. We are then engaged in mere playing with concepts. We construct an artificial opposition, but we can find no content for the second of these opposites, seeing that no content for a particular thing can be found except in perception. [111]
Every kind of reality which is assumed to exist outside the sphere of perception and conception must be relegated to the limbo of unverified hypotheses. To this category belongs the “thing-in-itself.” It is, of course, quite natural that a Dualistic thinker should be unable to find the connection between the world-principle which he hypothetically assumes and the facts that are given in experience. For the hypothetical world-principle itself a content can be found only by borrowing it from experience and shutting one’s eyes to the fact of the borrowing. Otherwise it remains an empty and meaningless concept, a mere form without content. In this case the Dualistic thinker generally asserts that the content of this concept is inaccessible to our knowledge. We can know only that such a content exists, but not what it is. In either case it is impossible to transcend Dualism. Even though one were to import a few abstract elements from the world of experience into the content of the thing-in-itself, it would still remain impossible to reduce the rich concrete life of experience to those few elements, which are, after all, themselves taken from experience. Du Bois-Reymond lays it down that the imperceptible atoms of matter produce sensation and feeling by means of their position and motion, and then infers from this premise that we can never find a satisfactory explanation of how matter and motion produce sensation and feeling, for “it is absolutely and [112]for ever unintelligible that it should be other than indifferent to a number of atoms of carbon, hydrogen, and nitrogen, etc., how they lie and move, how they lay or moved, or how they will lie and will move. It is in no way intelligible how consciousness can come into existence through their interaction.” This conclusion is characteristic of the whole tendency of this school of thought. Position and motion are abstracted from the rich world of percepts. They are then transferred to the fictitious world of atoms. And then we are astonished that we fail to evolve concrete life out of this principle of our own making, which we have borrowed from the world of percepts.
That the Dualist, working as he does with a completely empty concept of the thing-in-itself, can reach no explanation of the world, follows from the very definition of his principle which has been given above.
In any case, the Dualist finds it necessary to set impassable barriers to our faculty of knowledge. A follower of the Monistic theory of the world knows that all he needs to explain any given phenomenon in the world is to be found within this world itself. What prevents him from finding it can be only chance limitations in space and time, or defects of his organisation, i.e., not of human organisation in general, but only of his own.
It follows from the concept of knowledge, as defined by us, that there can be no talk of any limits of knowledge. Knowledge is not a [113]concern of the universe in general, but one which men must settle for themselves. External things demand no explanation. They exist and act on one another according to laws which thought can discover. They exist in indivisible unity with these laws. But we, in our self-hood, confront them, grasping at first only what we have called percepts. However, within ourselves we find the power to discover also the other part of reality. Only when the Self has combined for itself the two elements of reality which are indivisibly bound up with one another in the world, is our thirst for knowledge stilled. The Self is then again in contact with reality.
The presuppositions for the development of knowledge thus exist through and for the Self. It is the Self which sets itself the problems of knowledge. It takes them from thought, an element which in itself is absolutely clear and transparent. If we set ourselves questions which we cannot answer, it must be because the content of the questions is not in all respects clear and distinct. It is not the world which sets questions to us, but we who set them to ourselves.
I can imagine that it would be quite impossible for me to answer a question which I happened to find written down somewhere, without knowing the universe of discourse from which the content of the question is taken.
In knowledge we are concerned with questions which arise for us through the fact that [114]a world of percepts, conditioned by time, space, and our subjective organisation, stands over against a world of concepts expressing the totality of the universe. Our task consists in the assimilation to one another of these two spheres, with both of which we are familiar. There is no room here for talking about limits of knowledge. It may be that, at a particular moment, this or that remains unexplained because, through chance obstacles, we are prevented from perceiving the things involved. What is not found to-day, however, may easily be found to-morrow. The limits due to these causes are only contingent, and must be overcome by the progress of perception and thought.
Dualism makes the mistake of transferring the opposition of subject and object, which has meaning only within the perceptual world, to pure conceptual entities outside this world. Now the distinct and separate things in the perceptual world remain separated only so long as the perceiver refrains from thinking. For thought cancels all separation and reveals it as due to purely subjective conditions. The Dualist, therefore, transfers to entities transcending the perceptual world abstract determinations which, even in the perceptual world, have no absolute, but only relative, validity. He thus divides the two factors concerned in the process of knowledge, viz., percept and concept, into four: (1) the object in itself; (2) the percept which the subject has of the [115]object; (3) the subject; (4) the concept which relates the percept to the object in itself. The relation between subject and object is “real”; the subject is really (dynamically) influenced by the object. This real process does not appear in consciousness. But it evokes in the subject a response to the stimulation from the object. The result of this response is the percept. This, at length, appears in consciousness. The object has an objective (independent of the subject) reality, the percept a subjective reality. This subjective reality is referred by the subject to the object. This reference is an ideal one. Dualism thus divides the process of knowledge into two parts. The one part, viz., the production of the perceptual object by the thing-in-itself, he conceives of as taking place outside consciousness, whereas the other, the combination of percept with concept and the latter’s reference to the thing-in-itself, takes place, according to him, in consciousness.
With such presuppositions, it is clear why the Dualist regards his concepts merely as subjective representations of what is really external to his consciousness. The objectively real process in the subject by means of which the percept is produced, and still more the objective relations between things-in-themselves, remain for the Dualist inaccessible to direct knowledge. According to him, man can get only conceptual representations of the [116]objectively real. The bond of unity which connects things-in-themselves with one another, and also objectively with the individual minds (as things-in-themselves) of each of us, exists beyond our consciousness in a Divine Being of whom, once more, we have merely a conceptual representation.
The Dualist believes that the whole world would be dissolved into a mere abstract scheme of concepts, did he not posit the existence of real connections beside the conceptual ones. In other words, the ideal principles which thinking discovers are too airy for the Dualist, and he seeks, in addition, real principles with which to support them.
Let us examine these real principles a little more closely. The na?ve man (Na?ve Realist) regards the objects of sense-experience as realities. The fact that his hands can grasp, and his eyes see, these objects is for him sufficient guarantee of their reality. “Nothing exists that cannot be perceived” is, in fact, the first axiom of the na?ve man; and it is held to be equally valid in its converse: “Everything which is perceived exists.” The best proof for this assertion is the na?ve man’s belief in immortality and in ghosts. He thinks of the soul as a fine kind of matter perceptible by the senses which, in special circumstances, may actually become visible to the ordinary man (belief in ghosts).
In contrast with this, his real, world, the Na?ve Realist regards everything else, especially [117]the world of ideas, as unreal, or “merely ideal.” What we add to objects by thinking is merely thoughts about the objects. Thought adds nothing real to the percept.
But it is not only with reference to the existence of things that the na?ve man regards perception as the sole guarantee of reality, but also with reference to the existence of processes. A thing, according to him, can act on another only when a force actually present to perception issues from the one and acts upon the other. The older physicists thought that very fine kinds of substances emanate from the objects and penetrate through the sense-organs into the soul. The actual perception of these substances is impossible only because of the coarseness of our sense-organs relatively to the fineness of these substances. In principle, the reason for attributing reality to these substances was the same as that for attributing it to the objects of the sensible world, viz., their kind of existence, which was conceived to be analogous to that of perceptual reality.
The self-contained being of ideas is not thought of by the na?ve mind as real in the same sense. An object conceived “merely in idea” is regarded as a chimera until sense-perception can furnish proof of its reality. In short, the na?ve man demands, in addition to the ideal evidence of his thinking, the real evidence of his senses. In this need of the na?ve man lies the ground for the origin of the [118]belief in revelation. The God whom we apprehend by thought remains always merely our idea of God. The na?ve consciousness demands that God should manifest Himself in ways accessible to the senses. God must appear in the flesh, and must attest his Godhead to our senses by the changing of water into wine.
Even knowledge itself is conceived by the na?ve mind as a process analogous to sense-perception. Things, it is thought, make an impression on the mind, or send out copies of themselves which enter through our senses, etc.
What the na?ve man can perceive with his senses he regards as real, and what he cannot perceive (God, soul, knowledge, etc.) he regards as analogous to what he can perceive.
On the basis of Na?ve Realism, science can consist only in an exact description of the content of perception. Concepts are only means to this end. They exist to provide ideal counterparts of percepts. With the things themselves they have nothing to do. For the Na?ve Realist only the individual tulips, which we can see, are real. The universal idea of tulip is to him an abstraction, the unreal thought-picture which the mind constructs for itself out of the characteristics common to all tulips.
Na?ve Realism, with its fundamental principle of the reality of all percepts, contradicts experience, which teaches us that the content of percepts is of a transitory nature. The tulip [119]I see is real to-day; in a year it will have vanished into nothingness. What persists is the species “tulip.” This species is, however, for the Na?ve Realist merely an idea, not a reality. Thus this theory of the world finds itself in the paradoxical position of seeing its realities arise and perish, while that which, by contrast with its realities, it regards as unreal endures. Hence Na?ve Realism is compelled to acknowledge the existence of something ideal by the side of percepts. It must include within itself entities which cannot be perceived by the senses. In admitting them, it escapes contradicting itself by conceiving their existence as analogous to that of objects of sense. Such hypothetical realities are the invisible forces by means of which the objects of sense-perception act on one another. Another such reality is heredity, the effects of which survive the individual, and which is the reason why from the individual a new being develops which is similar to it, and by means of which the species is maintained. The soul, the life-principle permeating the organic body, is another such reality which the na?ve mind is always found conceiving in analogy to realities of sense-perception. And, lastly, the Divine Being, as conceived by the na?ve mind, is such a hypothetical entity. The Deity is thought of as acting in a manner exactly corresponding to that which we can perceive in man himself, i.e., the Deity is conceived anthropomorphically. [120]
Modern Physics traces sensations back to the movements of the smallest particles of bodies and of an infinitely fine substance, called ether. What we experience, e.g., as warmth is a movement of the parts of a body which causes the warmth in the space occupied by that body. Here again something imperceptible is conceived on the analogy of what is perceptible. Thus, in terms of perception, the analogon to the concept “body” is, say, the interior of a room, shut in on all sides, in which elastic balls are moving in all directions, impinging one on another, bouncing on and off the walls, etc.
Without such assumptions the world of the Na?ve Realist would collapse into a disconnected chaos of percepts, without mutual relations, and having no unity within itself. It is clear, however, that Na?ve Realism can make these assumptions only by contradicting itself. If it would remain true to its fundamental principle, that only what is perceived is real, then it ought not to assume a reality where it perceives nothing. The imperceptible forces of which perceptible things are the bearers are, in fact, illegitimate hypotheses from the standpoint of Na?ve Realism. But because Na?ve Realism knows no other realities, it invests its hypothetical forces with perceptual content. It thus transfers a form of existence (the existence of percepts) to a sphere where the only means of making any assertion concerning such existence, viz., sense-perception, is lacking. [121]
This self-contradictory theory leads to Metaphysical Realism. The latter constructs, beside the perceptible reality, an imperceptible one which it conceives on the analogy of the former. Metaphysical Realism is, therefore, of necessity Dualistic.
Wherever the Metaphysical Realist observes a relation between perceptible things (mutual approach through movement, the entrance of an object into consciousness, etc.), there he posits a reality. However, the relation of which he becomes aware cannot be perceived but only expressed by means of thought. The ideal relation is thereupon arbitrarily assimilated to something perceptible. Thus, according to this theory, the world is composed of............