ii KANT'S BASIC EPISTEMOLOGICAL QUESTION
KANT IS GENERALLY CONSIDERED
to be the founder of epistemology in the
modern sense. However, the history of philosophy before Kant contains
a number of investigations which must be considered as more than mere
beginnings of such a science. Volkelt points to this in his standard
work on epistemology, saying that critical treatments of this science
began as early as Locke.
[ 78 ]
However, discussions which to-day come under the heading of epistemology
[ 79 ]
can be found as far back as in the
philosophy of ancient Greece. Kant then went into every aspect of all
the relevant problems, and innumerable thinkers following in his
footsteps went over the ground so thoroughly that in their works or in
Kant's are to be found repetitions of all earlier attempts to solve
these problems. Thus where a factual rather than a historical
study of epistemology is concerned, there is no danger of omitting anything
important if one considers only the period since the appearance of Kant's
Critique of Pure Reason.
[ 80 ]
All earlier achievements in this field have been repeated since Kant.
Kant's fundamental question concerning epistemology is: How are
synthetical judgments a priori possible? Let us consider whether or
not this question is free of presuppositions. Kant formulates it
because he believes that we can arrive at certain, unconditional
knowledge only if we can prove the validity of synthetical judgments a
priori. He says:
“In the solution of the above problem is comprehended at the same time
the possibility of the use of pure reason in the foundation and
construction of all sciences which contain theoretical knowledge a
priori of objects.”
[ 81 ]
“Upon the solution of this problem depends the
existence or downfall of the science of metaphysics.”
[ 82 ]
Is this problem as Kant formulates it, free of all presuppositions?
Not at all, for it says that a system of absolute, certain knowledge
can be erected only on a foundation of judgments that are synthetical
and acquired independently of all experience. Kant calls a judgment
“synthetical” where the concept of the predicate brings to the
concept of the subject something which lies completely outside the subject
— “although it stands in connection with the subject,”
[ 83 ]
by contrast, in analytical judgment, the predicate merely expresses something
which is already contained (though hidden) in the subject. It would be out of
place here to go into the extremely acute objections made by
Johannes Rehmke
[ 84 ]
to this classification of judgments. For our present purpose it
will suffice to recognize that we can arrive at true knowledge only
through judgments which add one concept to another in such a way that
the content of the second was not already contained — at least
for us — in the first. If, with Kant, we wish to call this
category of judgment synthetical, then it must be agreed that
knowledge in the form of judgment can only be attained when the connection
between predicate and subject is synthetical in this sense. But the position
is different in regard to the second part of Kant's question, which
demands that these judgments must be acquired a priori, i.e.,
independent of all experience. After all, it is conceivable that such
judgments might not exist at all. A theory of knowledge must leave
open, to begin with, the question of whether we can arrive at a
judgment solely by means of experience, or by some other means as
well. Indeed, to an unprejudiced mind it must seem that for something
to be independent of experience in this way is impossible. For
whatever object we are concerned to know, we must become aware of it
directly and individually, that is, it must become experience. We
acquire mathematical judgment too, only through direct experience of
particular single examples. This is the case even if we regard them, with
Otto Liebmann
[ 85 ]
as rooted in a certain faculty of our
consciousness. In this case, we must say: This or that proposition
must be valid, for, if its truth were denied, consciousness would be
denied as well; but we could only grasp its content, as knowledge,
through experience in exactly the same way as we experience a process
in outer nature. Irrespective of whether the content of such a
proposition contains elements which guarantee its absolute validity or
whether it is certain for other reasons, the fact remains that we
cannot make it our own unless at some stage it becomes experience for
us. This is the first objection to Kant's question.
The second consists in the fact that at the beginning of a theoretical
investigation of knowledge, one ought not to maintain that no valid
and absolute knowledge can be obtained by means of experience. For it
is quite conceivable that experience itself could contain some
characteristic feature which would guarantee the validity of insight
gained by means of it.
Two presuppositions are thus contained in Kant's formulation of the
question. One presupposition is that we need other means of gaining
knowledge besides experience, and the second is that all knowledge
gained through experience is only approximately valid. It does not
occur to Kant that these principles need proof, that they are open to
doubt. They are prejudices which he simply takes over from dogmatic
philosophy and then uses as the basis of his critical investigations.
Dogmatic philosophy assumes them to be valid, and simply uses them to
arrive at knowledge accordingly; Kant makes the same assumptions and
merely inquires under what conditions they are valid. But suppose they
are not valid at all? In that case, the edifice of Kant's doctrine has
no foundation whatever.
All that Kant brings forward in the five paragraphs preceding his
actual formulation of the problem, is an attempt to prove that
mathematical judgments are synthetical (an attempt which
Robert Zimmermann,
[ 86 ]
if he does not refute it, at least shows it to be highly
questionable). But the two assumptions discussed above are retained as
scientific prejudices. In the
Critique of Pure Reason
[ 87 ]
it is said:
“Experience no doubt teaches us that this or that object is
constituted in such and such a manner, but not that it could not
possibly exist otherwise.” “Experience never exhibits strict and
absolute, but only assumed and comparative universality (by
induction).”
In Prolegomena
[ 88 ]
we find it said:
“Firstly, as regards the sources of metaphysical knowledge, the
very conception of the latter shows that these cannot be empirical. Its
principles (under which not merely its axioms, but also its
fundamental conceptions are included) must consequently never be
derived from experience, since it is not physical but metaphysical
knowledge, i.e., knowledge beyond experience, that is wanted.”
And finally Kant says:
“Before all, be it observed, that proper mathematical propositions are
always judgments a priori, and not empirical, because they carry along
with them the conception of necessity, which cannot be given by
experience. If this be demurred to, it matters not; I will then limit
my assertion to pure mathematics, the very conception of which implies
that it consists of knowledge altogether non-empirical and a priori.”
[ 89 ]
No matter where we open the
Critique of Pure Reason
we find that all the investigations pursued in it are based on these
dogmatic principles.
Cohen
[ 90 ]
and
Stadler
[ 91 ]
attempt to prove that Kant has
established the a priori nature of mathematical and purely scientific
principles. However, all that the
Critique of Pure Reason
attempts to show can be summed up as follows: Mathematics and pure natural
science are a priori sciences; from this it follows that the form of all
experiences must be inherent in the subject itself. Therefore, the
only thing left that is empirically given is the material of
sensations. This is built up into a system of experiences, the form of
which is inherent in the subject. The formal truths of a priori
theories have meaning and significance only as principles which
regulate the material of sensation; they make experience possible, but
do not go further than experience. However, these formal truths are
the synthetical judgment a priori, and they must — as condition
necessary for experience — extend as far as experience itself. The
Critique of Pure Reason
does not at all prove that mathematics and
pure science are a priori sciences but only establishes their sphere
of validity, pre-supposing that their truths are acquired
independently of experience. Kant, in fact, avoids discussing the
question of proof of the a priori sciences in that he simply excludes
that section of mathematics (see conclusion of Kant's last statement
quoted above) where even in his own opinion the a priori nature is
open to doubt; and he limits himself to that section where he believes
proof can be inferred from the concepts alone. Even Johannes Volkelt
finds that:
“Kant starts from the positive assumption that a necessary and
universal knowledge exists as an actual fact. These presuppositions
which Kant never specifically attempted to prove, are so contrary to a
proper critical theory of knowledge that one must seriously ask
oneself whether the
Critique of Pure Reason
is valid as critical epistemology.”
Volkelt does find that there are good reasons for answering this
question affirmatively, but he adds: “The critical conviction of
Kant's theory of knowledge is nevertheless seriously disturbed by this
dogmatic assumption.”
[ 92 ]
It is evident from this that Volkelt, too, finds that the
Critique of Pure Reason
as a theory of knowledge, is not free of presuppositions.
O. Liebmann,
Hölder,
Windelband,
Ueberweg,
Ed. v. Hartmann
[ 93 ]
and
Kuno Fischer,
[ 94 ]
hold essentially similar views on this point, namely, that
Kant bases his whole argument on the assumption that knowledge of pure
mathematics and natural science is acquired a priori.
That we acquire knowledge independently of all experience, and that
the insight gained from experience is of general value only to a
limited extent, can only be conclusions derived from some other
investigation. These assertions must definitely be preceded by an
examination both of the nature of experience and of knowledge.
Examination of experience could lead to the first principle;
examination of knowledge, to the second.
In reply to these criticisms of Kant's critique of reason, it could be
said that every theory of knowledge must first lead the reader to
where the starting point, free of all presuppositions, is to be found.
For what we possess as knowledge at any moment in our life is far
removed from this point, and we must first be led back to it
artificially. In actual fact, it is a necessity for every
epistemologist to come to such a purely didactic arrangement
concerning the starting point of this science. But this must always be
limited merely to showing to what extent the starting point for
cognition really is the absolute start; it must be presented in purely
self evident, analytical sentences and, unlike Kant's argument,
contain no assertions which will influence the content of the
subsequent discussion. It is also incumbent on the epistemologist to
show that his starting point is really free of all presuppositions.
All this, however, has nothing to do with the nature of the starting
point itself, but is quite independent of it and makes no assertions
about it. Even when he begins to teach mathematics, the teacher must
try to convince the pupil that certain truths are to be understood as
axioms. But no one would assert that the content of the axioms is made
dependent on these preliminary considerations.
[In the chapter titled
“The Starting Point of Epistemology,”
I shall show to what extent my discussion fulfils
these conditions.]
In exactly the same way
the epistemologist must show in his introductory remarks how one can
arrive at a starting point free of all presuppositions; yet the actual
content of this starting point must be quite independent of these
considerations. However, anyone who, like Kant, makes definite,
dogmatic assertions at the very outset, is certainly very far from
fulfilling these conditions when he introduces his theory of
knowledge.
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