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 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.
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 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 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 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 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 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
naïve man (Naïve 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 naïve 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 naïve 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 Naïve Realist regards
everything else, especially 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
naïve 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 naïve
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 naïve man demands, in addition to the
ideal evidence of his thinking, the real evidence of his senses. In
this need of the naïve man lies the ground for the origin of the
belief in revelation. The God whom we apprehend by thought remains
always merely our idea of God. The naïve 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 naïve 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 naïve 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 Naïve 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 Naïve 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.
Naïve 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 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 Naïve 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 Naïve 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 naïve mind is always found conceiving in analogy to realities
of sense-perception. And, lastly, the Divine Being, as conceived by the
naïve 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.
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 Naïve Realist would collapse
into a disconnected chaos of percepts, without mutual relations,
and having no unity within itself. It is clear, however, that Naïve
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 Naïve Realism. But because Naïve 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.
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 the objects of
perception which are in ceaseless flux, arising and disappearing,
and of imperceptible forces by which the perceptible objects are
produced, and which are permanent.
Metaphysical Realism is a self-contradictory mixture of Naïve Realism
and Idealism. Its forces are imperceptible entities endowed with the
qualities proper to percepts. The Metaphysical Realist has made up
his mind to acknowledge in addition to the sphere for the existence
of which he has an instrument of knowledge in sense-perception,
the existence of another sphere for which this instrument fails, and
which can be known only by means of thought. But he cannot make up
his mind at the same time to acknowledge that the mode of existence
which thought reveals, viz., the concept (or idea), has equal rights
with percepts. If we are to avoid the contradiction of imperceptible
percepts, we must admit that, for us, the relations which thought
traces between percepts can have no other mode of existence than that
of concepts. If one rejects the untenable part of Metaphysical Realism,
there remains the concept of the world as the aggregate of percepts
and their conceptual (ideal) relations. Metaphysical Realism, then,
merges itself in a view of the world according to which the principle
of perceptibility holds for percepts, and that of conceivability
for the relations between the percepts. This view of the world
has no room, in addition to the perceptual and conceptual worlds,
for a third sphere in which both principles, the so-called "real"
principle and the "ideal" principle, are simultaneously valid.
When the Metaphysical Realist asserts that, beside the ideal relation
between the perceived object and the perceiving subject, there
must be a real relation between the percept as "thing-in-itself"
and the subject as "thing-in-itself" (the so-called individual
mind), he is basing his assertion on the false assumption of a real
process, imperceptible but analogous to the processes in the world
of percepts. Further, when the Metaphysical Realist asserts that we
stand in a conscious ideal relation to our world of percepts, but
that to the real world we can have only a dynamic (force) relation,
he repeats the mistake we have already criticised. We can talk of a
dynamic relation only within the world of percepts (in the sphere of
the sense of touch), but not outside that world.
Let us call the view which we have just characterised, and into
which Metaphysical Realism merges when it discards its contradictory
elements, Monism, because it combines one-sided Realism and Idealism
into a higher unity.
For Naïve Realism, the real world is an aggregate of percepts; for
Metaphysical Realism, reality belongs not only to percepts but also to
imperceptible forces; Monism replaces forces by ideal relations which
are supplied by thought. These relations are the laws of nature. A law
of nature is nothing but the conceptual expression for the connection
of certain percepts.
Monism is never called upon to ask whether there are any principles of
explanation for reality other than percepts and concepts. The Monist
knows that in the whole realm of the real there is no occasion for
this question. In the perceptual world, as immediately apprehended, he
sees one-half of reality; in the union of this world with the world of
concepts he finds full reality. The Metaphysical Realist might object
that, relatively to our organisation, our knowledge may be complete in
itself, that no part may be lacking, but that we do not know how the
world appears to a mind organised differently from our own. To this
the Monist will reply, Maybe there are intelligences other than human;
and maybe also that their percepts are different from ours, if they
have perception at all. But this is irrelevant to me for the following
reasons. Through my perceptions, i.e., through this specifically human
mode of perception, I, as subject, am confronted with the object. The
nexus of things is thereby broken. The subject reconstructs the nexus
by means of thought. In doing so it re-inserts itself into the context
of the world as a whole. As it is only through the Self, as subject,
that the whole appears rent in two between percept and concept, the
reunion of those two factors will give us complete knowledge. For
beings with a different perceptual world (e.g., if they had twice
our number of sense-organs) the nexus would appear broken in another
place, and the reconstruction would accordingly have to take a form
specifically adapted to such beings. The question concerning the
limits of knowledge troubles only Naïve and Metaphysical Realism,
both of which see in the contents of mind only ideal representations
of the real world. For, to these theories, whatever falls outside
the subject is something absolute, a self-contained whole, and
the subject's mental content is a copy which is wholly external to
this absolute. The completeness of knowledge depends on the greater
or lesser degree of resemblance between the representation and the
absolute object. A being with fewer senses than man will perceive less
of the world, one with more senses will perceive more. The former's
knowledge will, therefore, be less complete than the latter's.
For Monism, the situation is different. The point where the unity of
the world appears to be rent asunder into subject and object depends
on the organisation of the percipient. The object is not absolute
but merely relative to the nature of the subject. The bridging of the
gap, therefore, can take place only in the quite specific way which
is characteristic of the human subject. As soon as the Self, which in
perception is set over against the world, is again re-inserted into the
world-nexus by constructive thought, all further questioning ceases,
having been but a result of the separation.
A differently constituted being would have a differently constituted
knowledge. Our own knowledge suffices to answer the questions which
result from our own mental constitution.
Metaphysical Realism must ask, What is it that gives us our
percepts? What is it that stimulates the subject?
Monism holds that percepts are determined by the subject. But
in thought the subject has, at the same time, the instrument for
transcending this determination of which it is itself the author.
The Metaphysical Realist is faced by a further difficulty when he
seeks to explain the similarity of the world-views of different human
individuals. He has to ask himself, How is it that my theory of the
world, built up out of subjectively determined percepts and out of
concepts, turns out to be the same as that which another individual
is also building up out of these same two subjective factors? How, in
any case, is it possible for me to argue from my own subjective view
of the world to that of another human being? The Metaphysical Realist
thinks he can infer the similarity of the subjective world-views of
different human beings from their ability to get on with one another
in practical life. From this similarity of world-views he infers
further the likeness to one another of individual minds, meaning by
"individual mind" the "I-in-itself" underlying each subject.
We have here an inference from a number of effects to the character
of the underlying causes. We believe that after we have observed
a sufficiently large number of instances, we know the connection
sufficiently to know how the inferred causes will act in other
instances. Such an inference is called an inductive inference. We
shall be obliged to modify its results, if further observation yields
some unexpected fact, because the character of our conclusion is,
after all, determined only by the particular details of our actual
observations. The Metaphysical Realist asserts that this knowledge
of causes, though restricted by these conditions, is quite sufficient
for practical life.
Inductive inference is the fundamental method of modern Metaphysical
Realism. At one time it was thought that out of concepts we could
evolve something that would no longer be a concept. It was thought that
the metaphysical reals, which Metaphysical Realism after all requires,
could be known by means of concepts. This method of philosophising
is now out of date. Instead it is thought that from a sufficiently
large number of perceptual facts we can infer the character of the
thing-in-itself which lies behind these facts. Formerly it was from
concepts, now it is from percepts, that the Realist seeks to evolve
the metaphysically real. Because concepts are before the mind in
transparent clearness, it was thought that we might deduce from them
the metaphysically real with absolute certainty. Percepts are not
given with the same transparent clearness. Each fresh one is a little
different from others of the same kind which preceded it. In principle,
therefore, anything inferred from past experience is somewhat modified
by each subsequent experience. The character of the metaphysically real
thus obtained can therefore be only relatively true, for it is open
to correction by further instances. The character of Von Hartmann's
Metaphysics depends on this methodological principle. The motto on
the title-page of his first important book is, "Speculative results
gained by the inductive method of Science."
The form which the Metaphysical Realist at the present day gives to his
things-in-themselves is obtained by inductive inferences. Consideration
of the process of knowledge has convinced him of the existence of an
objectively-real world-nexus, over and above the subjective world which
we know by means of percepts and concepts. The nature of this reality
he thinks he can determine by inductive inferences from his percepts.