perception. Yet, at the same time, the distinction between thought and
perception, although not simple, is real. For although our previous
thought affects our perception and we see things already classified, see
books, and tables, and chairs, not merely coloured surfaces, yet we can
distinguish between simple immediate perception and the process of
thought which begins when we ask, What is that? _i.e._ when we begin to
make judgments.
The characteristic of thought, according to Kant, is synthesis, or
putting together, and all synthesis is the work of the mind. When we
begin to describe and classify the contents of our perception, we pick
out separate qualities from the continuous whole we perceive, and group
them together. This grouping is, of course, determined by the
likenesses and differences which we perceive everywhere, but we do not,
in judging, confine ourselves to noticing likeness and difference. For
any content of our perception has some point of resemblance, and some of
difference with any other. We are concerned with likenesses that go
with or are the signs of other likenesses. On the basis of perceived
likeness we erect the notion of things and qualities of a certain kind.
In doing this we go beyond what we see, and unite and arrange the
contents of our perception through concepts. That is what we are doing
when we say that is a so-and-so. For example, if I say that rock is
like a dog, I am simply expressing a likeness I perceive. I do not
imply that the rock is therefore alive or will bark; I am not going
beyond how the rock looks; but if I say that object is a dog, I assert
that all that is implied in being a dog will hold of that object, _i.e._
that it will have a certain appearance and behaviour, which is known. I
can anticipate, therefore, how it will behave, look, and sound under
certain circumstances. All these phenomena, the appearance, the barking,
and running, though I may perceive them at different times and places,
are grouped together in the judgment, "That is a dog." This is what
Kant means by saying, "Concepts depend on functions. By function I mean
the unity of the act of arranging different representations under one
common representation." Concepts, therefore, always refer to
perception, and it is by means of concepts that we are enabled to
introduce such order into what we perceive, that we can anticipate from
what we perceive what we shall perceive. "Perceptions without concepts
are blind." Without concepts what we perceive would not lead us in any
way beyond what is immediately given. "Thoughts without contents are
empty." Concepts are nothing, and have no meaning apart from the
contents of perception which they unify.
Most of these concepts are what is called empirical. We get at them by
observing likenesses and differences in what we perceive, and observing
which are significant and important, and which are what we call
accidental. Science, in its discovery of laws, is only carrying further
this process which is implied in all simple judgments. By observing
likenesses and differences, their uniformities and variations, and
discovering those which are a key to the rest, we improve our concepts,
and thereby have more knowledge of what we call natural laws, and can
more and more anticipate experience. With these empirical concepts and
their development Kant is not concerned. But there are certain concepts
of which Hume had observed that they are not obtained in the ordinary
way from an examination of the contents of experience. The two with
which he chiefly concerned himself were substance and cause. These
concepts seems to play an especially important part in the ordering and
arranging of the concepts of experience. For the work of science, in
moving from a simple observation of likenesses and differences to a
knowledge of empirical laws, depends upon certain assumptions or
principles, like the principle of causation or the principle of the
conservation of energy. These principles imply concepts not derived,
like the others, from generalisation from experience; they are the
synthetic a priori judgments which, as we have seen, constituted a
special problem for Kant.
Kant is first concerned to ask where these a priori concepts come from,
and how many of them there are. This inquiry he calls the metaphysical
deduction of the categories. Having answered that question, he then
goes on to ask by what right we assume these principles in our dealing
with experience. This, the most important and difficult section of the
_Critique_, he calls the transcendental deduction of the categories.
Most concepts, as we saw, are empirical. We take certain likenesses and
differences we observe as the mark of a real unity in the things. The
different natures of different things we do not fully know, but we
distinguish them by the different uniformities we observe, and in order
to explain our experience we assume the unity underlying these perceived
likenesses. Iron, dog, fire, are names for the natures of things which
we see manifested in our experience. The concept, then, is got from
what we perceive, though it stands for something more than we perceive.
How, then, can there be any concepts which are not got from the
empirical differences of things we perceive? Let us take such a concept
as substance, and see whether we can discover where it comes from.
Locke had been puzzled by discovering that he could not, in any object,
find anything which was its substantiality. Calling anything a
substance is not like saying that it is hard, or green, or heavy; we are
not concerned with specific differences in things, but we are not
therefore saying what is meaningless. There is something, namely
substance, which we can distinguish from the hardness, or colour, or
weight that we perceive. That something we do not perceive; we assume
it whenever we talk of a thing being hard, and green, and heavy. A
thing's substantiality is just the unity of its perceivable qualities.
But such a unity is implied in the concept of any object. Substance,
then, is a name for one of the general principles implied in our
assuming that what we perceive are real objects.
Kant generalises the result of this inquiry into particular concepts of
this kind. He holds that a priori concepts or categories (_i.e._ the
concepts which we do not get from empirical differences of things) stand
for principles implied in thinking of things as objects or in judging.
If we want, therefore, to find out the number of the categories, we must
ask how many different kinds of unity are implied in judgment, or what
are the conditions of judging any object. Kant does not here help, but
rather misleads us in this inquiry. For he unfortunately thought that
the different kinds of judgment could be discovered without further ado
by taking the list given in formal logic. He therefore first makes a
list of categories, based on the logical forms of judgment, and then
tries to show the connection between these categories and the principles
which were, as he had discovered, assumed in the mathematical sciences.
The actual movement of his thought is, I think, different. He asks if
there are any general conditions implied in all judgment. His answer is
that all judgments, all statements, that is, which claim to be true,
imply determination of time and space. From that determination certain
principles can be deduced. If time and space are implied in all
judging, then these principles will equally be implied, and will hold of
all things which can be objects for us.
It will be easier to understand Kant's arguments if we invert the order
of the _Critique_ and begin with examining the nature of the principles
of the understanding or of one of them.
The categories which are of importance in Kant's argument are quantity,
quality, substance, causation, and reciprocity, and necessity,
possibility, and actuality. The last three are less important than the
others, and we shall not deal with them.
To the first five of these categories correspond the following
principles:
(1) Quantity. "All phenomena are, with reference to their perception,
extensive quantities."
(2) Quality. "In all phenomena the real, which is the object of a
sensation, has intensive quantity, that is, a degree."
The last three are classed under a general heading of _Analogies of
Experience_, whose principle is: "Experience is possible only through
the representation of a necessary connection of perceptions." They are
(3) _The principle of the permanence of substance_. "In all changes of
phenomena the substance is permanent, and its quantum is neither
increased nor diminished in nature."
(4) _Principle of the succession of time, according to the Law of
Causality_. "All changes take place according to the law of connection
between cause and effect."
(5) _Principle of co-existence, according to the law of reciprocity or
community_. "All substances, so far as they can be perceived as
co-existent in space, are always affecting each other reciprocally."
These principles, Kant points out, are assumed in the sciences of
applied mathematics. The application of geometry to the world we
experience assumes that all phenomena are extensive quantities; physics
assumes that quantitative expression can be given to the qualities of
objects other than their size, their weight, _e.g._, and all scientific
determination of change assumes the three principles which Kant calls
analogies of experience: the permanence or conservation of amount in
changes, the necessary connection of things in time, and the reciprocal
interdependence of things which exist at the same time. These
principles are not proved by science; their validity is assumed in all
scientific investigation. On what, then, does it rest?
We shall follow Kant's argument more easily if we take his account of
one of these principles--the principle of causation. For what is said
of that will hold, with necessary changes, of the others, and, as we
have noticed, it was Hume's criticism of causation which first led Kant
to formulate the critical problem. Hume had pointed out that we had
never such insight into causal connection as to be able, from mere
inspection of a cause, to foretell the effect without any reference to
experience. He declared, on the contrary, that there was no difference
between observed succession and causation so far as concerned the
objects observed. In each case we see first one thing and then another.
The difference, then, between mere succession and causal connection can
only be in us, in the way we come to feel about certain successions we
observe. In technical language, the necessity of causation is
subjective.
How does Kant answer this position? He begins, as is usual with him, by
taking the problem a little further back. Causation is a connection we
predicate between what we see at one time, and what we see at another.
Now if we take into account only the fact that we see one thing at one
time and another thing at another, there is no difference between what
we see when we successively see two things which we judge to co-exist,
and when we see two things one of which we judge to have succeeded the
other in time. Hume, therefore, proved too much. His argument would
show that we have no grounds for distinguishing between apprehension of
succession and succession in apprehending, but such a distinction is the
basis of our apprehension and understanding of change or movement. If,
then, we examine how we distinguish between apprehension of succession
and succession in apprehending, we may see on what the principle of
causation is based.
An instance will help to make this point clear. Suppose that I am
sitting in a room, and look first at the door and then turn round and
look at the window. There are two successive acts of apprehending; the
content of the first is the door, of the second, the window, but the
succession, I say, is in my apprehending. The door and the window have
co-existed all the time. Suppose, again, that I look out of the window
and see a cab in front of the house opposite, come back into the room,
and then look out again and see the cab in front of a house further
down. Here, again, are two successive acts of apprehending, the content
of the first houses with cab in front of one house, of the second houses
with cab in front of another. This time I say the houses have gone on
co-existing, but the cab has moved. The difference in what I see this
time is due not to me, but to the cab. The succession is in the thing
apprehended. If we just think of the contents apprehended, we have
first A, then B, and say A and B co-exist in the first instance, and
have CD and CE, and say D and E have been successive in the other. Why
in the second case do we not say when we look out of the window the
second time: Here is another row of houses, which, though they look
exactly the same as the ones I saw last time, have got the cab in a
different place? That is the land of thing one does say in a dream.
Why would it be inadmissible in waking life?
Let us first ask how we ever come to make the distinction between change
in the content of our perception, which is due to change in us, and
change in the things we perceive. Look out of a window into a busy
street. As we look certain things remain the same, the houses opposite,
the lamp-posts, and so on, but other things change. The permanence of
part of the contents guarantees us that the change we perceive is not
due to us: if it were, these would change also. Therefore it must be in
certain of the things. Change is perceived against a background that is
permanent and does not change. But any such particular perception is,
of course, very limited. We do not see all the world at once, and we
only come to know a larger extent of reality by means of memory, which
enables us to put together what we see at one time with what we see at
another. We have got to try and understand how it is that we make this
distinction, which is clear to us in small isolated bits of experience,
hold of all experience. Now if reality did not change, and we were
conscious of our own movements, we could go from one point to another of
reality and back again, and could be aware that the changes in our
perception were all due, not to change in reality, but to us--were our
history. We should know that the different things we saw were
co-existing all the time, and we should, in describing them, try to
describe them, as in a map, as we should perceive them if we saw them
all at once. The succession would be subjective, the co-existence
objective. If we perceived nothing but change, we should be incapable
of distinguishing between our changes and the change outside us, for all
succession in our experiencing would be experience of what was
successive, and there could be no distinction between psychology and
science. Our experience of reality is not like either of these
suppositions, but like both of them combined. Some succession of our
experiencing is experience of the co-existing, some experience of
succession.
Reality stretches out beyond us in space, some of it changing and some
of it permanent; we cannot tell simply from the difference in what we
perceive whether the difference comes from change in us or change in the
thing. We can tell that only on the assumption that we are having
fragmentary views of a whole that is continuous. The only continuity we
know is the continuity of our own experience made possible by memory,
and we try to interpret that experience in the light of the larger
continuity of the world which our experience breaks up. As we go from
one place to another, notice now this thing, now that, we can test
interpretations made on this assumption. Wrong interpretations are
those which make our experience inconsistent. If we thought that what
happened at one time had no relation with what happened at another, that
anything might happen any time, our experience and our own life would be
the merest jumble. Our experience attains consistency only as we learn
more and more to disentangle the differences in experience which come
from our changes, from the changes and the variety which are part of the
whole connected system of reality, of which we see now one fragment,
then another. The distinction between succession in our apprehending
and apprehension of succession, which is the basis of all experience of
change, implies the recognition of change as not arbitrary but part of a
connected system of reality. As Kant puts it in his formulation of the
principle of the analogies of experience, "Experience is only possible
by means of the representation of a necessary connection of
perceptions."
But if our perception of reality is fragmentary, how can we think of
reality as other than fragmentary, how can we fill up the gaps? Only by
thinking of the whole as a connected system in space and time. For it
is the nature of space and time that they can be thought of
independently of the specific nature of the things in space and time,
and that the space and time we perceive in any one experience must be
thought of as parts of an all-embracing space and an all-embracing time.
We cannot follow the whole history of a change from A to B, we can only
say that, if our experience is to have any consistency, we must think
that the fact that we first saw A and then saw B implies in this case
that the change from A to B is part of the continuous system of change
in time, that it is determined in time. But to think of an event as
determined in time is not to think of it as determined by time, for time
in itself could not produce one thing more than another. It is to think
of it as determined by the nature of what precedes it in time. We
therefore conclude that like causes have like effects; for, if anything
could cause anything, we should never know that change in what we
observed was due to change in us--in the position of our bodies,
_e.g._--and the experience of objective change would be impossible.
The principle does not tell us of itself what causes what. That can
only be discovered by empirical investigation. That is necessary
because we do not, as we seem to have assumed above, simply see one
thing becoming another. We see parts of all kinds of changes. Hence
succession may be objective but not causal. Science has, by observation
and experiment, to disentangle and isolate different changes, but it
could not do this without assuming the principle of causality.
Causation, then, and the other assumptions of the physical sciences, are
shown by Kant to be "grounds of the possibility of experience." We
cannot deny them without denying elementary distinctions in our
experience, without which life would be a chaos, and which are assumed
and justified every moment. While Kant thus demonstrates the validity
of such principles, he is also insistent on the limitations of their
application. They are principles which give consistency to experience,
but must not be applied save in reference to what we experience. They
apply, in his words, "only to phenomena." The purport of this
limitation can, again, be most easily seen by examining the principle of
causality. By means of that principle we connect one event with
another, but the reality is not two different but connected events, but
a continuous process. The continuous process escapes us, because our
perception of it is fragmentary and discontinuous. Inasmuch as a
judgment of causal connection asserts that the events we separately
notice are connected, it is true, but it is false if taken to imply that
reality consists of a series of discontinuous events or stages which are
yet connected. Such an assumption would mean, in Kant's words, that
causation is applied not to phenomena (things as they appear to us), but
to things in themselves (things considered apart from the manner in
which they appear to us). If we realise its falsehood, we can, he
thinks, evade the contradictions which he examines in the _Dialectic_.
*CHAPTER V*
*THE ANTINOMIES AND CRITICISM OF THE PROOFS OF
THE EXISTENCE OF GOD*
So far we have been considering the positive side of Kant's argument,
his attempt to confirm the validity of the principles of science. We
must now notice the negative side, his attempt to limit the application
of these principles, and his denial of the possibility of knowledge in
certain spheres.
We saw that Kant in his _Prolegomena_ summed up the argument of the
three chief divisions of the _Critique_ as an answer to the questions:
How is mathematics possible? How is pure science of nature possible?
and, How is metaphysics possible? He qualified the last question by
adding "as a natural disposition of the mind." The argument of the
_Dialectic_ is that metaphysics, in the sense of inquiry into objects
which transcend the bounds of experience, is not possible as a science,
but that metaphysical questions arise naturally from the nature of human
reason. They cannot be answered. All we can do is to see why we cannot
answer them.
Kant thought of knowledge as a process of extending the bounds of
perception, of piecing together the fragmentary glimpses we get of the
world, stretching them out in spatial and temporal determinations that
go beyond what we have actually experienced, connecting and linking up
the events which we perceive discontinuously. As science extends, the
range of our knowledge widens, but the process of extension never
reaches its completion. There are always more facts to be discovered
and explained. Science, therefore, can never rest content with its
achievements, but must always demand that the investigation of
conditions should be pushed further back and on. From this sense of the
incompleteness of all actual knowledge, and of all there is that might
be but is not known, arises what Kant calls an ideal of reason, a demand
that, in all investigation into the conditioned, we should go on till we
come to the totality of conditions. This ideal he holds to be
serviceable and necessary. It has, however, a natural tendency to pass
from an ideal to an idea, and in so doing it gives rise to the
contradictions with which the _Dialectic_ is concerned. If all our
investigation is governed by the thought that it must go on until it
reaches completion, we naturally speculate on the fulfilment of that
ideal, and try to form an idea of that totality of conditions, of how we
should think the world if we knew it in its completeness. Herein we
hypostatize the ideal or make it an idea, and we fall into
contradiction; for we cannot really know the whole without knowing all
its parts. If we give up the slow and never-completed process of
knowing one part after another, and try to jump to the idea of the
whole, we reach quite contrary results, as we apply to the conception of
the whole one or other of two assumptions implied in our investigation
of the parts.
Kant sharply distinguishes between the principles of the pure
understanding and the ideas of reason. The former are implied in all
our knowledge, and the fact that experience is not chaotic confirms them
at every moment. The second are ideals which guide knowledge, but are
never realised. He calls them ideas of reason, because it is the
special task of reason to lay down rules for the proper and complete
working of the understanding. This task, he thinks, is exemplified in
the logical nature of the syllogism which brings into unity the
judgments of the understanding. As he used the forms of judgment as a
guiding thread to discover a complete list of categories of the
understanding, so he uses the forms of syllogism to discover a complete
list of the ideas of reason. In both cases Kant's reference to logical
forms is far-fetched. Actually the list in the _Dialectic_ seems to be
influenced by a number of considerations not always consistent.