KANT.
The suit between empiricism and rationalism had continued for centuries,
but still awaited final decision. Are all our ideas the result of
experience, or are they (wholly or in part) an original possession of the
mind? Are they received from without (by perception), or produced from
within (by self-activity)? Is knowledge a product of sensation or of pure
thought? All who had thus far taken part in this discussion had resembled
partisans or advocates rather than disinterested judges. They had given
less attention to investigation than to the defense of the traditional
theses of their schools; they had not endeavored to obtain results, but
to establish results already determined; and, along with real arguments,
popular appeals had not been despised. Each of the opposing schools had
given variations on a definite theme, and whenever timid attempts had been
made to bring the two melodies into harmony they had met with no approval.
The proceedings thus far had at least made it evident to the unbiased
hearer that each of the two parties made extravagant claims, and, in the
end, fell into self-contradiction. If the claim of empiricism is true, that
all our concepts arise from perception, then not only the science of the
suprasensible, which it denies, but also the science of the objects of
experience, about which it concerns itself, is impossible. For perception
informs us concerning single cases merely, it can never comprehend all
cases, it yields no necessary and universal truth; but knowledge which is
not apodictically valid for every reasoning being and for all cases is
not worthy the name. The very reasons which were intended to prove the
possibility of knowledge give a direct inference to its impossibility. The
empirical philosophy destroys itself, ending with Hume in skepticism and
probabilism. Rationalism is overtaken by a different, and yet an analogous
fate--it breaks up into a popular eclecticism. It believes that it
has discovered an infallible criterion of truth in the clearness and
distinctness of ideas, and a sure example for philosophical method in the
method of mathematics. In both points it is wrong. The criterion of
truth is insufficient, for Spinoza and Leibnitz built up their opposing
theories--the pantheism of the one and the monadology of the other--from
equally clear and distinct conceptions; tried by this standard
individualism is just as true as pantheism. Mathematics, again, does not
owe its unquestioned acceptance and cogent force to the clearness and
distinctness of its conceptions, but to the fact that these are capable
of construction in intuition. The distinction between mathematics and
metaphysics was overlooked, namely, that mathematical thought can transform
its conceptions into intuitions, can generate its objects or sensuously
present them, which philosophical thought is not in a position to do. The
objects of the latter must be given to it, and to the human mind they are
given in no other way than through sensuous intuition. Metaphysics seeks
to be a science of the real, but it is impossible to conjure being out of
thought; reality cannot be proved from concepts, it can only be felt. In
making the unperceivable and suprasensible (the real nature of things, the
totality of the world, the Deity, and immortality) the special object
of philosophy, rationalism looked on the understanding as a faculty of
knowledge by which objects are given. In reality objects can never be given
through concepts; these only render it possible to think objects given
in some other way (by intuition). It is true that concepts of the
suprasensible exist, but nothing can be known through them, there is
nothing intuitively given to be subsumed under them.
With this failure to perceive the intuitive element in mathematics was
joined the mistake of overlooking its synthetic character. The syllogistic
method of presentation employed in the Euclidean geometry led to the belief
that the more special theorems had been derived from the simpler ones, and
these from the axioms, by a process of conceptual analysis; while the fact
is that in mathematics all progress is by intuition alone, the syllogism
serving merely to formulate and explain truths already attained, but not to
supply new ones. Following the example of mathematics thus misunderstood,
the mission of philosophy was made to consist in the development of
the truths slumbering in pregnant first principles by means of logical
analysis. If only there were metaphysical axioms! If we only did not
demand, and were not compelled to demand, of true science that it increase
our knowledge, and not merely give an analytical explanation of knowledge.
When once the clearness and distinctness of conceptions had been taken
in so purely formal a sense, it was inevitable that in the end, as
productivity became less, the principle should be weakened down to a mere
demand for the explanation and elucidation of the metaphysical ideas
present in popular consciousness. Thus the rationalistic current lost
itself in the shallow waters of the Illumination, which soon gave as
ready a welcome to the empirical theories--since these also were able to
legitimate themselves by clear and distinct conceptions--as it had given
to the results of the rationalistic systems.
It was thus easy to see that each of the contending parties had been guilty
of one-sidedness, and that in order to escape this a certain mean must be
assumed between the two extremes; but it was a much more difficult matter
to discover the due middle ground. Neither of the opposing standpoints is
so correct as its defenders believe, and neither so false as its opponents
maintain. Where, then, on either side, does the mistaken narrowness begin,
and how far does the justification of each extend?
The conflict centers, first, about the question concerning the origin of
human knowledge and the sphere of its validity. Rationalism is justified
when it asserts that some ideas do not come from the senses. If knowledge
is to be possible, some concepts cannot originate in perception, those,
namely, by which knowledge is constituted, for if they should, it would
lack universality and necessity. The sole organ of universally valid
knowledge is reason. Empiricism, on the other hand, is justified when it
asserts that the experiential alone is knowable. Whatever is to be knowable
must be given as a real in sensuous intuition. The only organ of reality is
sensibility. Rationalism judges correctly concerning the origin of the
most important classes of ideas; empiricism concerning the sphere of their
validity. The two may be thus combined: some concepts (those which produce
knowledge) take their origin in reason or are _a priori_, but they are
valid for objects of experience alone. The conflict concerns, secondly, the
use of the deductive (syllogistic) or the inductive method. Empiricism,
through its founder Bacon, had recommended induction in place of the barren
syllogistic method, as the only method which would lead to new discoveries.
It demands, above all things, the extension of knowledge. Rationalism, on
the contrary, held fast to the deductive method, because the syllogism
alone, in its view, furnishes knowledge valid for all rational beings. It
demands, first of all, universality and necessity in knowledge. Induction
has the advantage of increasing knowledge, but it leads only to empirical
and comparative, not to strict universality. The syllogism has the
advantage of yielding universal and necessary truth, but it can only
explicate and establish knowledge, not increase it. May it not be possible
so to do justice to the demands of both that the advantages which they seek
shall be combined, and the disadvantages which have been feared, avoided?
Are there not cognitions which increase our knowledge (are _synthetic_)
without being empirical, which are universally and necessarily valid
(_a priori_) without being analytic? From these considerations arises the
main question of the _Critique of Pure Reason_: How are synthetic judgments
_a priori_ possible?
The philosophy of experience had overestimated sense and underestimated the
understanding, when it found the source of all knowledge in the faculty of
perception and degraded the faculty of thought to an almost wholly inactive
recipient of messages coming to it from without. From the standpoint of
empiricism concepts (Ideas) deserve confidence only in so far as they can
legitimate themselves by their origin in sensations (impressions). It
overlooks the _active_ character of all knowing. Among the rationalists,
on the other hand, we find an underestimation of the senses and an
overestimation of the understanding. They believe that sense reveals
only the deceptive exterior of things, while reason gives their true
non-sensuous essence. That which the mind perceives of things is deceptive,
but that which it thinks concerning them is true. The former power is the
faculty of confused, the latter the faculty of distinct knowledge. Sense is
the enemy rather than the servant of true knowledge, which consists in the
development and explication of pregnant innate conceptions and principles.
These philosophers forget that we can never reach reality by conceptual
analysis; and that the senses have a far greater importance for knowledge
than merely to give it an impulse; that it is they which supply the
understanding with real objects, and so with the content of knowledge.
Beside the (formal) activity (of the understanding), cognition implies a
passive factor, a reception of impressions. Neither sense alone nor the
understanding alone produces knowledge, but both cognitive powers are
necessary, the active and the passive, the conceptual and the intuitive.
Here the question arises, How do concept and intuition, sensuous and
rational knowledge, differ, and what is the basis of their congruence?
Notwithstanding their different points of departure and their variant
results, the two main tendencies of modern philosophy agree in certain
points. If the conflict between the two schools and their one-sidedness
suggested the idea of supplementing the conclusions of the one by those of
the other, the recognition of the incorrectness of their common
convictions furnished the occasion to go beyond them and to establish a
new, a higher point of view above them both, as also above the eclecticism
which sought to unite the opposing principles. The errors common to both
concern, in the first place, the nature of judgment and the difference
between sensibility and understanding. Neither side had recognized that
the peculiar character of judgment consists in _active connection_. The
rationalists made judgment an active function, it is true, but a mere
activity of conscious development, of elucidation and analytical inference,
which does not advance knowledge a single step. The empiricists described
it as a process of comparison and discrimination, as the mere perception
and recognition of the relations and connections already existing between
ideas; while in reality judgment does not discover the relations and
connections of representations, but itself establishes them. In the former
case the synthetic moment is ignored, in the latter the active moment. The
imperfect view of judgment was one of the reasons for the appearance of
extreme theories concerning the origin of ideas in reason or in perception.
Rationalism regards even those concepts which have a content as innate,
whereas it is only formal concepts which are so. Empiricism regards all,
even the highest formal concepts (the categories), as abstracted from
experience, whereas experience furnishes only the content of knowledge,
and not the synthesis which is necessary to it. On the one hand too much,
and on the other too little, is regarded as the original possession of the
understanding. The question "What concepts are innate?" can be decided only
by answering the further question, What are the concepts through which the
faculty of judgment connects the representations obtained from experience?
These connective concepts, these formal instruments of synthesis are
_a priori_. The agreement of the two schools is still greater in regard to
the relation of sense and understanding, notwithstanding the apparently
sharp contrast between them. The empiricist considers thought transformed,
sublimated perception, while the rationalist sees in perception only
confused and less distinct thought. For the former concepts are faded
images of sensations, for the latter sensations are concepts which have not
yet become clear; the difference is scarcely greater than if the one should
call ice frozen water, and the other should prefer to call water melted
ice. Both arrange intuition and thought in a single series, and derive the
one from the other by enhancement or attenuation. Both make the mistake of
recognizing only a difference in degree where a difference in kind exists.
In such a case only an energetic dualism can afford help. Sense and
understanding are not one and the same cognitive power at different stages,
but two heterogeneous faculties. Sensation and thought are not different in
degree, but in kind. As Descartes began with the metaphysical dualism of
extension and thought, so Kant begins with the noëtical dualism of
intuition and thought.
Much more serious, however, than any of the mistakes yet mentioned was
a sin of omission of which the two schools were alike guilty, and the
recognition and avoidance of which constituted in Kant's own eyes the
distinctive character of his philosophy and its principiant-advance beyond
preceding systems. The pre-Kantian thinker had proceeded to the discussion
of knowledge without raising _the question of the possibility of
knowledge_. He had approached things in the full confidence that the human
mind was capable of cognizing them, and with a naïve trust in the power of
reason to possess itself of the truth. His trust was naïve and ingenuous,
because the idea that it could deceive him had never entered his mind. Now
no matter whether this belief in man's capacity for knowledge and in the
possibility of knowing things is justifiable or not, and no matter how
far it may be justifiable, it was in any case untested; so that when the
skeptic approached with his objections the dogmatist was defenseless.
All previous philosophy, so far as it had not been skeptical, had been,
according to Kant's expression, dogmatic; that is, it had held as an
article of faith, and without precedent inquiry, that we possess the power
of cognizing objects. It had not asked _how_ this is possible; it had not
even asked what knowledge is, what may and must be demanded of it, and by
what means our reason is in a position to satisfy such demands. It had left
human intelligence and its extent uninvestigated. The skeptic, on the other
hand, had been no more thorough. He had doubted and denied man's capacity
for knowledge just as uncritically as the dogmatist had believed and
presupposed it. He had directed his ingenuity against the theories of
dogmatic philosophy, instead of toward the fundamental question of the
possibility of knowledge. Human intelligence, which the dogmatist had
approached with unreasoned trust and the skeptic with just as unreasoned
distrust, is subjected, according to the plan of the critical philosopher,
to a searching examination. For this reason Kant termed his standpoint
"criticism," and his undertaking a "Critique of Reason." Instead of
asserting and denying, he investigates how knowledge arises, of what
factors it is composed, and how far it extends. He inquires into the origin
and extent of knowledge, into its sources and its limits, into the grounds
of its existence and of its legitimacy. The Critique of Reason finds itself
confronted by two problems, the second of which cannot be solved until
after the solution of the first. The investigation of the sources of
knowledge must precede the inquiry into the extent of knowledge. Only after
the conditions of knowledge have been established can it be ascertained
what objects are attainable by it. Its sphere cannot be determined except
from its origin.
Whether the critical philosopher stands nearer to the skeptic or to the
dogmatist is rather an idle question. He is specifically distinct from
both, in that he summons and guides the reason to self-contemplation, to
a methodical examination of its capacity for knowledge. Where the one had
blindly trusted and the other suspected and denied, he investigates; they
overlook, he raises the question of the possibility of knowledge. The
critical problem does not mean, Does a faculty of knowledge exist? but, Of
what powers is it composed? are all objects knowable which have been so
regarded? Kant does not ask whether, but how and by what means, knowledge
is possible. Everyone who gives himself to scientific reflection must
postulate that knowledge is possible, and the demand of the noëtical
theorists of the day for a philosophy absolutely without assumptions is
quite incapable of fulfillment. Nay, in order to be able to begin his
inquiry at all, it was necessary for Kant to assume still more special
postulates; for that a cognition of cognition is possible, that there is a
critical, self-investigating reason could, at first, be only a matter of
belief. This would not have excluded a supplementary detailed statement
concerning the _how_ of this self-knowledge, concerning the organ of the
critical philosophy. But Kant never gave one, and the omission subsequently
led to a sharp debate concerning the character and method of the Critique
of Reason. On this point, if we may so express it, Kant remained a
dogmatist.
Kant felt himself to be the finisher of skepticism; but this was chiefly
because he had received the strongest impulse to the development of his
critique of knowledge from Hume's inquiries concerning causation. Brought
up in the dogmatic rationalism of the Wolffian school, to which he
remained true for a considerable period as a teacher and writer (till about
1760), although at the same time he was inquiring with an independent
spirit, Kant was gradually won over through the influence of the English
philosophy to the side of empirical skepticism. Then--as the result, no
doubt, of reading the _Nouveaux Essais_ of Leibnitz, published in
1765--he returned to rationalistic principles, until finally, after a
renewal of empirical influences,[1] he took the position crystallized in
the _Critique of Pure Reason_, 1781, which, however, experienced still
other, though less considerable, changes in the sequel, just as in itself
it shows the traces of previous transformations.
[Footnote 1: Cf. H. Vaihinger's _Kommentar zu Kants Kritik der reinen
Vernunft_, vol. i., 1881, pp. 48-49. This is a work marked by acuteness,
great industry, and an objective point of view which merits respect. The
second volume, which treats of the Transcendental Aesthetic, appeared in
1892.]
It would be a most interesting task to trace in the writings which belong
to Kant's pre-critical period the growth and development of the fundamental
critical positions. Here, however, we can only mention in passing the
subjects of his reflection and some of the most striking anticipations and
beginnings of his epoch-making position. Even his maiden work, _Thoughts on
the True Estimation of Vis Viva_, 1747, betokens the mediating nature of
its author. In this it is argued that when men of profound and penetrating
minds maintain exactly opposite opinions, attention must be chiefly
directed to some intermediate principle to a certain degree compatible with
the correctness of both parties. The question under discussion was whether
the measure of _vis viva_ is equal, as the Cartesians thought, to the
product of the mass into the velocity, or, according to the Leibnitzians,
to the product of the mass into the square of the velocity. Kant's
unsatisfactory solution of the problem--the law of Descartes holds for
dead, and that of Leibnitz for living forces--drew upon him the derision
of Lessing, who said that he had endeavored to estimate living forces
without having tested his own. A similar tendency toward compromise--this
time it is a synthesis of Leibnitz and Newton--is seen in his
_Habilitationsschrift, Principiorum Primorum Cognitionis Metaphysicae Nova
Dilucidatio_, 1755, and in the dissertation _Monadologia Physica_, 1756.
The former distinguishes between _ratio essendi_ and _ratio cognoscendi_,
rejects the ontological argument, and defends determinism against Crusius
on Leibnitzian grounds. In the _Physical Monadology_ Kant gives his
adherence to dynamism (matter the product of attraction and repulsion), and
makes the monads or elements of body fill space without prejudice to
their simplicity. A series of treatises is devoted to subjects in natural
science: The Effect of the Tides in retarding the Earth's Rotation; The
Obsolescence of the Earth; Fire (Inaugural Dissertation), Earthquakes, and
the Theory of the Winds. The most important of these, the _General Natural
History and Theory of the Heavens_, 1755, which for a long time remained
unnoticed, and which was dedicated to Frederick II., developed the
hypothesis (carried out forty years later by Laplace in ignorance of Kant's
work) of the mechanical origin of the universe and of the motion of the
planets. It presupposes merely the two forces of matter, attraction and
repulsion, and its primitive chaotic condition, a world-mist with elements
of different density. It is noticeable that Kant acknowledges the failure
of the mechanical theory at two points: it is brought to a halt at the
origin of the organic world and at the origin of matter. The mechanical
cosmogony is far from denying creation; on the contrary, the proof that
this well-ordered and purposive world necessarily arose from the regular
action of material forces under law and without divine intervention, can
only serve to support our assumption of a Supreme Intelligence as the
author of matter and its laws; the belief is necessary, just because
nature, even in its chaotic condition, can act only in an orderly and
regular way.
The empirical phase of Kant's development is represented by the writings
of the 60's. _The False Subtlety of the Four Syllogistic Figures_, 1762,
asserts that the first figure is the only natural one, and that the others
are superfluous and need reduction to the first. In the _Only Possible
Foundation for a Demonstration of the Existence of God_, 1763, which, in
the seventh Reflection of the Second Division, recapitulates the cosmogony
advanced in the _Natural History of the Heavens_, the discussions
concerning being ("existence" is absolute position, not a predicate which
increases the sum of the qualities but is posited in a merely relative
way), and the conclusion, prophetical of his later point of view, "It is
altogether necessary that we should be _convinced_ of the existence of God,
but not so necessary that his existence should be _demonstrated_" are more
noteworthy than the argument itself. This runs: All possibility presupposes
something actual wherein and whereby all that is conceivable is given as
a determination or a consequence. That actuality the destruction of which
would destroy all possibility is absolutely necessary. Therefore there
exists an absolutely necessary Being as the ultimate real ground of all
possibility; this Being is one, simple, unchangeable, eternal, the _ens
realissimum_ and a spirit. The _Attempt to introduce the Notion of
Negative Quantities into Philosophy_, 1763, distinguishes--contrary to
Crusius--between logical opposition, contradiction or mere negation (_a_
and _not-a_, pleasure and the absence of pleasure, power and lack of
power), and real opposition, which cannot be explained by logic (+_a_ and
-_a_, pleasure and pain, capital and debts, attraction and repulsion;
in real opposition both determinations are positive, but in opposite
directions). Parallel with this it distinguishes, also, between logical
ground and real ground. The prize essay, _Inquiry concerning the Clearness_
(Evidence) _of the Principles of Natural Theology and Ethics_, 1764, draws
a sharp distinction between mathematical and metaphysical knowledge, and
warns philosophy against the hurtful imitation of the geometrical method,
in place of which it should rather take as an example the method which
Newton introduced into natural science. Quantity constitutes the object of
mathematics, qualities, the object of philosophy; the former is easy and
simple, the latter difficult and complicated--how much more comprehensible
the conception of a trillion is than the philosophical idea of freedom,
which the philosophers thus far have been unable to make intelligible.
In mathematics the general is considered under symbols _in concrete_, in
philosophy, by means of symbols _in abstracto_; the former constructs its
object in sensuous intuition, while the object of the latter is given
to it, and that as a confused concept to be decomposed. Mathematics,
therefore, may well begin with definitions, since the conception which is
to be explained is first brought into being through the definition, while
philosophy must begin by seeking her conceptions. In the former the
definition is first in order, and in the latter almost always last; in the
one case the method is synthetic, in the other it is analytic. It is the
function of mathematics to connect and compare clear and certain concepts
of quantity in order to draw conclusions from them; the function of
philosophy is to analyze concepts given in a confused state, and to make
them detailed and definite. Philosophy has also this disadvantage, that
it possesses very many undecomposable concepts and undemonstrable
propositions, while mathematics has only a few such. "Philosophical truths
are like meteors, whose brightness gives no assurance of their permanence.
They vanish, but mathematics remains. Metaphysics is without doubt the most
difficult of all human sciences _(Einsichten)_, but a metaphysic has
never yet been written"; for one cannot be so kind as to "apply the term
philosophy to all that is contained in the books which bear this title." In
the closing paragraphs, on the ultimate bases of ethics, the stern features
of the categorical imperative are already seen, veiled by the English
theory of moral sense, while the attractive _Observations on the Feeling
of the Beautiful and the Sublime_, which appeared in the same year, still
naïvely follow the empirical road.
The empirical phase reaches its skeptical termination in the satire _Dreams
of a Ghost-seer explained by the Dreams of Metaphysics_, 1766, which pours
out its ingenious sarcasm impartially on spiritualism and on the assumed
knowledge of the suprasensible. Here Kant is already clearly conscious of
his new problem, a theory of the limits of human reason, conscious also
that the attack on this problem is to be begun by a discussion of the
question of space. This second question had been for many years a frequent
subject of his reflections;[1] and it was this part of the general critical
problem that first received definitive solution. In the Latin dissertation
_On the Form and Principles of the Sensible and Intelligible World_, 1770,
which concludes the pre-critical period, and which was written on the
occasion of his assumption of his chair as ordinary professor, the
critique of sensibility, the new theory of space and time, is set forth in
approximately the same form as in the _Critique of Pure Reason_, while the
critique of the understanding and of reason, the theory of the categories
and the Ideas and of the sphere of their validity, required for its
completion the intellectual labor of several more years. For this essay,
_De Mundi Sensibilis atque Intelligibilis Forma et Principiis_, leaves
unchallenged the possibility of a knowledge of things in themselves and of
God, thus showing that its author has abandoned the skepticism maintained
in the _Dreams of a Ghost-seer_, and has turned anew to dogmatic
rationalism, whose final overthrow required another swing in the direction
of skeptical empiricism. In regard to the progress of this latter phase
of opinion, the letters to M. Herz are almost the only, though not very
valuable, source of information.
[Footnote 1: _New Theory of Motion and Rest_, 1758; _On the First Ground of
the Distinction of Positions in Space_, 1768; besides several of the works
mentioned above.]
The _Critique of Pure Reason_ appeared in 1781, much later than Kant had
hoped when he began a work on "The Limits of Sensibility and Reason," and a
second, altered edition in 1787.[1] After the _Prolegomena to every Future
Metaphysic which may present itself as Science_, 1783, had given a popular
form to the critical doctrine of knowledge, it was followed by the critical
philosophy of ethics in the _Foundation of the Metaphysics of Ethics_,
1785, and the _Critique of Practical Reason_, 1788; by the critical
aesthetics and teleology in the _Critique of Judgment_, 1790; and by the
critical philosophy of religion in _Religion within the Limits of Reason
Only_, 1793[2] (consisting of four essays, of which the first, "Of Radical
Evil," had already appeared in the _Berliner Monatsschrift_ in 1792). The
_Metaphysical Elements of Natural Science_, 1786, and the _Metaphysics
of Ethics_, 1797 (in two parts, "Metaphysical Elements of the Theory of
Right," and "Metaphysical Elements of the Theory of Virtue "), are devoted
to the development of the system. The year 1798 brought two more larger
works, the _Conflict of the Faculties_ and the _Anthropology_. Of the
reviews, that on Herder's _Ideen_ maybe mentioned, and among the minor
essays, the following: _Idea for a Universal History in a Cosmopolitan
Sense, Answer to the Question: What is Illumination f_ both in 1784;
_What does it mean to Orient oneself in Thought_? 1786; _On the Use of
Teleological Principles in Philosophy_, 1788; _On a Discovery according to
which all Recent Criticism of Pure Reason is to be superseded by a Previous
One_, 1790; _On the Progress of Metaphysics since the Time of Wolff; On
Philosophy in General, The End of all Things_, 1794; _On Everlasting
Peace_, 1795. Kant's _Logic_ was published by Jäsche in 1800; his _Physical
Geography_ and his _Observations on Pedagogics_ by F.T. Rink in 1803; his
lectures on the _Philosophical Theory of Religion_ (1817; 2d. ed., 1830)
and on _Metaphysics_ (1821; cf. Benno Erdmann in the _Philosophische
Monatshefte_, vol. xix. 1883, p. 129 _seq_., and vol. xx. 1884, p. 65
_seq_.) by Pölitz. If we may judge by the specimens given by Reicke in the
_Altpreussische Monatsschrift_, 1882-84, and by Krause himself,[3]
the promised publication of a manuscript of Kant's last years, now in
possession of the Hamburg pastor, Albrecht Krause, and which discusses the
transition from the metaphysical elements of natural science to physics,
will hardly meet the expectations which some have cherished concerning it.
Benno Erdmann has issued _Nachträge zu Kants Kritik der reinen Vernunft aus
Kants Nachlass_, 1881, and _Reflexionen Kants zur kritischen Philosophie
aus handschriftlichen Aufzeichnungen_--the first volume first _Heft
(Reflexionen zur Anthropologie_) appearing in 1882, the second volume
_(Reflexionen zur Kritik der reinen Vernunft, aus Kants Handexemplar
von Baumgartens Metaphysica)_ in 1884. Max Müller has made an English
translation of the _Critique of Pure Reason_, 2 vols., 1881.[4]
[Footnote 1: There has been much discussion and much has been written
concerning the relation of the two editions. In opposition to Schopenhauer
and Kuno Fischer it must be maintained that the alterations in the second
edition consist in giving greater prominence to realistic elements, which
in the first edition remained in the background, though present even
there.]
[Footnote 2: This publication was the occasion of a conflict between Kant
and the censorship concerning the right of free religious inquiry; cf.
Dilthey in the _Archiv für Geschichte der Philosophie_, vol. in. 1890, pp.
418-450.]
[Footnote 3: A. Krause: _I. Kant wider K. Fischer, zum ersten Male mit
Hülfe des verloren gewesenen Kantischen Hauptwerkes vertheidigt_, 1884 (in
reply, K. Fischer, _Das Streber- und Gründerthum in der Litteratur_,
1884); also, _Das nachgelassene Werk I. Kants, mit Belegen
populär-wissenschaftlich dargestellt_, 1888.]
[Footnote 4: Besides this (centenary) translation the English reader may
be referred to the earlier version of Meiklejohn in Bonn's Library; to the
versions of the _Prolegomena_ by Bax (also in Bonn's Library, and including
the _Metaphysical Elements of Natural Science_), and Mahaffy and Bernard,
new ed., 1889; to Abbot's _Kant's Theory of Ethics_, 4th ed., 1889,
containing the _Foundation of the Metaphysics of Ethics_ and the _Critique
of Practical Reason_ entire, with portions of the _Metaphysics of Ethics_
and _Religion within the Limits of Reason Only_; to Bernard's translation
of the _Kritik of Judgment_, 1892; and to Watson's _Selections from Kant_,
2d ed., 1888 (in Sneath's Modern Philosophers, 1892).--TR.]
The best complete edition of the works of Kant is the second edition of
Hartenstein, in eight volumes, 1867-68, which is chronologically arranged
and excellently gotten up. Simultaneously with the first edition of
Hartenstein in ten volumes, in 1838 _seq_., appeared the edition in twelve
volumes by K. Rosenkranz and F.W. Schubert (containing in the last volumes
a biography of Kant by Schubert, and a history of the Kantian philosophy by
Rosenkranz, 1842). Kehrbach's edition of the principal works in Reclam's
_Universal-Bibliothek_, with the pagination of the original and collective
editions (1877 _seq_.), is more valuable than Von Kirchmann's edition of
the complete works in his _Philosophische Bibliothek_.
Among the works on Kant those of Kuno Fischer (vols. iii.-iv. of the
_Geschichte der neueren Philosophie_, 3d ed., 1882; also Kant's _Leben und
die Grundlagen seiner Lehre_, 1860) take the first place. The writings of
Liebmann, Cohen, Stadler, Riehl, Volkelt, and others will be mentioned
later, in connection with the neo-Kantian movement; here we may give some
of the more important monographs and essays, selected from the enormously
developed Kantian literature:
Ad. Böhringer, _Kants erkenntnisstheoretischer Idealismus_, 1888;
K. Dieterich, _Die Kantische Philosophie in ihrer inneren
Entwickelungsgeschichte_, 2 parts, 1885 (first published separately,
_Kant und Newton_, 1877; _Kant und Rousseau_, 1878); W. Dilthey, _Aus
den Rostocker Kanthandschriften_ in the _Archiv für Geschichte der
Philosophie_, vols. ii.-iii. 1889-90; M.W. Drobisch, _Kants Ding an sich
und sein Erfahrungsbegriff_, 1885; B. Erdmann, _Kants Kritizismus in der
I. und II. Auflage der Kritik der reinen Vernunft_, 1878; the same, _Kants
Prolegomena herausgegeben und erläutert_, 1878, Introduction (in reply Emil
Arnoldt, _Kants Prolegomena nicht doppelt redigiert_, 1879; cf. also H.
Vaihinger, _Die Erdmann-Arnoldtsche Kontroverse_ in the _Philosophische
Monatshefte_, vol. xvi. 1880); Franz Erhardt, _Kritik der Kantischen
Antinomienlehre_, 1888; R. Eucken, _Ueber Bilder und Gleichnisse bei
Kant, Zeitschrift für Philosophie_, vol. lxxxiii, 1883, reprinted in his
_Beiträge zur Geschichte der neueren Philosophie_, 1886; F. Frederichs,
_Der phänomenale Idealismus Berkeleys und Kants_, 1871; the same, _Kants
Prinzip der Ethik_, 1879; Ed. von Hartmann, _Das Ding an sich und seine
Beschaffenheit_, 1871, in the 2d ed., 1875, and the 3d, 1885, entitled
_Kritische Grundlegung des transzendentalen Realismus_; C. Hebler,
_Kantiana_, in his _Philosophische Aufsätze_, 1869; Alfred Hegler, _Die
Psychologie in Kants Ethik_, 1891; A. Hölder, _Darstellung der Kantischen
Erkenntnisstheorie_, 1873 J. Jacobson, _Die Auffindung des Apriori_, 1876;
the same, _Ueber die Beziehungen zwischen Kategorien und Urtheilsformen_,
1877; Wilhelm Koppelmann, _Kants Lehre vom analytischen Urtheil, Philosoph.
Monatshefte_, vol. xxi, 1885; the same, _Lotzes Stellung zu Kants
Kritizismus, Zeitschrift für Philosophie_, vol. lxxxviii, 1886; the same,
_Kants Lehre vom kategorischen Imperativ_, 1888; the same, _Kant und die
Grundlagen der Christlichen Religion_, 1890; E. Laas, _Kants Analogien
der Erfahrung_, 1876; the same, _Einige Bemerkungen zur
Transzendentalphilosophie_, Strassburg _Abhandlungen_, 1884; J. Mainzer,
_Die kritische Epoche in der Lehre von der Einbildungskraft_, 1881; J.B.
Meyer, _Kants Psychologie_, 1870; F. Paulsen, _Was Kant uns sein kann,
Vierteljahrsschrift für wissenschaftliche Philosophie_, 1881; B. Pünjer,
_Die Religionslehre Kants_, 1874; R. Quaebicker, _Kants und Herbarts
metaphysische Grundansichten über das Wesen der Seele_, 1870; J. Rehmke,
_Physiologie und Kantianismus_, address in Eisenach, 1883; Rud. Reicke,
_Lose Blätter aus Kants Nachlass_, 1889 (on this H. Vaihinger in the
_Zeitschrift für Philosophie_, vol. xcvi. 1889); O. Riedel, _Die
monadologischen Bestimmungen in Kants Lehre vom Ding an sich_, dissertation
at Kiel, 1884; O. Schneider, _Die psychologische Entwickelung des Apriori_,
1883; the same, _Transzendentalpsychologie_, 1891; F. Staudinger,
_Noumena_, 1884; M. Steckelmacher, _Die formale Logik Kants_, Breslau
Prize Essay, 1879; A. Stern, _Die Beziehung Garves zu Kant,
nebst ungedruckten Briefen_, 1884; C. Stumpf, _Psychologie und
Erkenntnisstheorie, Abhandlungen der bayerischen Akademie der
Wissenschaften_, 1891; G. Thiele, _Kants intellectuelle Anschauung als
Grundbegriff seines Kritizismus_, 1876; the same, _Die Philosophie Kants
nach ihrem systematischen Zusammenhange und ihrer logischhistorischen
Entiwickelung_, I. (1) _Kants vorkritische Naturphilosophie_, 1882; (2)
_Kants vorkritische Erkenntnisstheorie_, 1887; Ad. Trendelenburg, _Ueber
eine Lücke in Kants Beweis von der ausschliessenden Subjectivität des
Raumes and der Zeit_ in vol. iii. of his _Historische Beiträge zur
Philosophie_, 1867; Ueberhorst, _Kants Lehre von dem Verhältnisse der
Kategorien zu der Erfahrung_, 1878; H. Vaihinger, _Eine Blattversetzung in
Kants Prolegomena, Philosoph. Monatshefte_, vol. xv. 1879; the same, _Zu
Kants Widerlegung des Idealismus_, Strassburg _Abhandlungen_, 1884; J.
Walter, _Zum Gedächtniss Kants, Festrede_, 1881; Th. Weber, _Zur Kritik der
Kantischen Erkenntnisstheorie_ (from the _Zeitschrift für Philosophie_),
1882; W. Windelband, _Ueber die verschiedenen Phasen der Kantischen Lehre
vom Ding an sich, Vierteljahrsschrift für wissenschaftliche Philosophie_,
1877 (cf. the same author's _Geschichte der neueren Philosophie_, § 58);
J. Witte, _Beiträge zum Verständniss Kants_, 1874; the same, _Kantischer
Kritizismus gegenüber unkritischem Dilettantismus_ (against A. Stöhr),
1885; Wohlrabe, _Kants Lehre vom Gewissen_, 1889; E. Zeller, _Ueber das
Kantische Moralprinzip_, 1880; R. Zimmermann, _Ueber Kants Widerlegung des
Idealismus von Berkeley_, 1871; the same, _Ueber Kants mathematisches
Vorurtheil und dessen Folgen_, 1871.
Popular expositions have been given by the following: K. Fortlage (in his
_Philos. Vorträge_, 1869); E. Last, _Mehr Licht! Die Haupsätze Kants und
Schopenhauers_, 1879; the same, _Die realistiche und die idealistische
Anschauung entwickelt an Kants Idealität von Raum und Zeit_, 1884; H.
Romundt, _Antaeus, neuer Aufbau der Lehre Kants über Seele, Freiheit,
und Gott_, 1882; the same, _Grundlegung zur Reform der Philosophie,
vereinfachte und erweiterte Darstellung von Kants Kritik der reinen
Vernunft_, 1885; the same, _Die Vollendung des Socrates, Kants Grundlegung
zur Reform der Sittenlehre_; the same, _Ein neuer Paulus, Kants Grundlegung
zu einer sicheren Lehre von der Religion_, 1886; the same, _Die drei Fragen
Kants_, 1887; A. Krause, _Populäre Darstellung von Kants Kritik der reinen
Vernunft_, 1881; K. Lasswitz, _Die Lehre Kants von der Idealität des
Raumes und der Zeit_, 1883; Wilhelm Münz, _Die Grundlagen der Kantischen
Erkenntnisstheorie_, 2d ed., 1885.
Among foreigners Villers, Cousin, Nolen, Desdouits, Cantoni, E. Caird [_\A
Critical Account of the Philosophy of Kant_, 1877; _The Critical Philosophy
of Immanuel Kant_, 2 vols., 1889], Adamson _[On the Philosophy of Kant_,
1879, and a valuable article in the _Encyclopedia Britannica_, 9th ed.,
vol. xiii.], Stirling [_Text-book to Kant_, 1881], [Watson, _Kant and his
English Critics_, 1881], Morris _Kant's Critique of Pure Reason_, Griggs's
Philosophical Classics, 1882, [Wallace, _Kant_, Blackwood's Philosophical
Classics, 1882; Porter, _Kant's Ethics_, Griggs's Philosophical Classics,
1886; Green, _Lectures_, Works, vol. ii., 1886.--Tr.], have among others
made contributions to Kantian literature. Of the older works we may mention
the dictionaries of E. Schmid, 1788, and Mellin (in six volumes), 1797
_seq_., the critique of the Kantian philosophy in the first volume of
Schopenhauer's chief work, 1819, and the essay of C.H. Weisse, _In
welchem Sinne hat sich die deutsche Philosophie jetzt wieder an Kant zu
orientieren_, 1847.
Kant's outward life was less eventful and less changeful than his
philosophical development.[1] Born in Königsberg in 1724, the son of J.G.
Cant, a saddler of Scottish descent, his home and school training were both
strict and of a markedly religious type. He was educated at the university
of his native city, and for nine years, from 1746 on, filled the place of
a private tutor. In 1755 he became _Docent_, in 1770 ordinary professor in
Königsberg, serving also for six years of this time as under-librarian. He
seldom left his native city and never the province. The clearness
which marked his extremely popular lectures on physical geography and
anthropology was due to his diligent study of works of travel, and to an
unusually acute gift of observation, which enabled him to draw from his
surroundings a comprehensive knowledge of the world and of man. He ceased
lecturing in 1797, and in 1804 old age ended a life which had always, even
in minute detail, been governed by rule. A man of extreme devotion to
duty, particularity, and love of truth, and an amiable, bright, and witty
companion, Kant belongs to the acute rather than to the profound thinkers.
Among his manifold endowments the tendency to combination and the faculty
of intuition (as the _Critique of Judgment_ especially shows) are present
to a noticeable degree, yet not so markedly as the power of strict analysis
and subtle discrimination. So that, although a mediating tendency is
rightly regarded as the distinguishing characteristic of the Kantian
thinking, it must also be remembered that synthesis is everywhere preceded
by a mighty work of analysis, and that this still exerts its power even
after the adjustment is complete. Thus Kant became the energetic defender
of a qualitative view of the world in opposition to the quantitative view
of Leibnitz, for which antitheses (_e.g._, sensation and thought, feeling
and cognition, good and evil, duty and inclination) fade into mere
differences of degree.
[Footnote 1: The following have done especially valuable service in the
investigation of the development of Kant's doctrine: Paulsen (_Versuch
einer Entwickelungsgeschichte der Kantischen Erkenntnisstheorie_, 1875),
B. Erdmann, Vaihinger, and Windelband. Besides Hume and Leibnitz, Newton,
Locke, Shaftesbury, Rousseau, and Wolff exercised an important influence
on Kant.]
In the beginning of this chapter we have indicated how the new ideal of
knowledge, under whose banner Kant brought about a reform of philosophy,
grew out of the conflict between the rationalistic (dogmatic) and the
empirical (skeptical) systems. This combines the Baconian ideal of the
extension of knowledge with the Cartesian ideal of certainty in knowledge.
It is synthetic judgments alone which extend knowledge, while analytic
judgments are explicative merely.[1] _A priori_ judgments alone are
perfectly certain, absolutely universal, and necessarily valid; while _a
posteriori_ judgments are subjectively valid merely, lack necessity, and,
at best, yield only relative universality.[2] All analytic judgments are _a
priori_, all empirical or _a posteriori_ judgments are synthetic. Between
the two lies the object of Kant's search. Do _synthetic judgments a priori_
exist, and how are they possible?
[Footnote 1: "All bodies are extended" is an analytic judgment; "all bodies
possess weight," a synthetic judgment. The former explicates the concept
of the subject by bringing into notice an idea already contained in it and
belonging to the definition as a part thereof; it is based on the law of
contradiction: an unextended body is a self-contradictory concept. The
latter, on the contrary, goes beyond the concept of the subject and adds
a predicate which had not been thought therein. It is experience which
teaches us that weight is joined to matter, a fact which cannot be derived
from the concept of matter. Almost all mathematical principles are
synthetic, and here, as will be shown, it is not experience but "pure
intuition" which permits us to go beyond the concept and add a new mark
to it.]
[Footnote 2: The Scholastics applied the term _a priori_ to knowledge from
causes (from that which precedes), and _a posteriori_ to knowledge from
effects. Kant, following Leibnitz and Lambert, uses the terms to designate
the antithesis, knowledge from reason and knowledge from experience. An _a
priori_ judgment is a judgment obtained without the aid of experience. When
the principle from which it is derived is also independent of experience it
is absolutely _a priori_, otherwise it is relatively _a priori_.]
Two sciences discuss the _how_, and a third the _if_ of such judgments,
which, at the same time, are ampliative and absolutely universal and
necessary. The first two sciences are pure mathematics and pure natural
science, of which the former is protected against doubt concerning its
legitimacy by its evident character, and the latter, by the constant
possibility of verification in experience; each, moreover, can point to
the continuous course of its development. All this is absent in the third
science, metaphysics, as science of the suprasensible, and to its great
disadvantage. Experiential verification is in the nature of things denied
to a presumptive knowledge of that which is beyond experience; it lacks
evidence to such an extent that there is scarcely a principle to be found
to which all metaphysicians assent, much less a metaphysical text-book
to compare with Euclid; there is so little continuous advance that it is
rather true that the later comers are likely to overthrow all that their
predecessors have taught. In metaphysics, therefore, which, it must be
confessed, is actual as a natural tendency, the question is not, as in
the other two sciences, concerning the grounds of its legitimacy, but
concerning this legitimacy itself. Mathematics and pure physics form
synthetic judgments _a priori_, and metaphysics does the same. But the
principles of the two former are unchallenged, while those of the third
are not. In the former case the subject for investigation is, Whence this
authority? in the latter case, Is she thus authorized?
Thus the main question, How are synthetic judgments _a priori_ possible?
divides into the subordinate questions, How is pure mathematics possible?
How is pure natural science possible, and, How is metaphysics (in two
senses: metaphysics in general, and metaphysics as science) possible? The
Transcendental _Aesthetic_ (the critique of sensibility or the faculty
of intuition) answers the first of these questions; the Transcendental
_Analytic_ (the critique of the understanding), the second; and the
Transcendental _Dialectic_ (the critique of "reason" in the narrower sense)
and the Transcendental _Doctrine of Method (Methodenlehre)_, the third. The
Analytic and the Dialectic are the two parts of the Transcendental "Logic"
(critique of the faculty of thought), which, together with the Aesthetic,
forms the Transcendental "Doctrine of Elements" _(Elementarlehre)_, in
contrast to the Doctrine of Method. The _Critique of Pure Reason_ follows
this scheme of subordinate division, while the _Prolegomena_ co-ordinates
all four parts in the manner first mentioned.
Let us anticipate the answers. Pure mathematics is possible, because there
are pure or _a priori intuitions_ (space and time), and pure natural
science or the metaphysics of phenomena, because there are _a priori
concepts_ (categories) _and principles_ of the pure understanding.
Metaphysics as a presumptive science of the suprasensible has been possible
in the form of unsuccessful attempts, because there are _Ideas_ or concepts
of reason which point beyond experience and look as though knowable objects
were given through them; but as real science it is not possible, because
the application of the categories is restricted to the limits of
experience, while the objects thought through the Ideas cannot be
sensuously given, and all assumed knowledge of them becomes involved in
irresolvable contradictions (antinomies). On the other hand, a science is
possible and necessary to teach the correct use of the categories, which
may be applied to phenomena alone, and of the Ideas, which may be applied
only to our knowledge of things (and our volition), and to determine the
origin and the limits of our knowledge--that is to say, a transcendental
philosophy. In regard to metaphysics (knowledge from pure reason), then,
this is the conclusion reached: Rejection of transcendent metaphysics (that
which goes beyond experience), recognition and development of immanent
metaphysics (that which remains within the limits of possible experience).
It is not possible as a metaphysic of things in themselves; it is possible
as a metaphysic of nature (of the totality of phenomena), and as a
metaphysic of knowledge (critique of reason).
The interests of the reason are not exhausted, however, by the question,
What can we know? but include two further questions, What ought we to do?
and, What may we hope? Thus to the metaphysics of nature there is added
a metaphysics of morals, and to the critique of theoretical reason, a
critique of practical reason or of the will, together with a critique of
religious belief. For even if a "knowledge" of the suprasensible is denied
to us, yet "practical" grounds are not wanting for a sufficiently certain
"conviction" concerning God, freedom, and immortality.
After carrying the question of the possibility of synthetic judgments _a
priori_ from the knowledge of nature over to the knowledge of our duty,
Kant raises it, in the third place, in regard to our judgment concerning
the subjective and objective purposiveness of things, or concerning their
beauty and their perfection, and adds to his critique of the intellect
and the will a critique of the faculty of aesthetic and teleological
_judgment_.
The Kantian philosophy accordingly falls into three parts, one theoretical,
one practical (and religious), one aesthetic and teleological.
* * * * *
Before advancing to our account of the first of these parts, a few
preliminary remarks are indispensable concerning the presuppositions
involved in Kant's critical work and on the method which he pursues. The
presuppositions are partly psychological, partly (as the classification of
the forms of judgment and inference, and the twofold division of judgments)
logical, either in the formal or the transcendental sense, and partly
metaphysical (as the thing in itself). Kant takes the first of these from
the psychology of his time, by combining the Wolffian classification of the
faculties with that of Tetens, and thus obtains six different faculties:
lower (sensuous) and higher (intellectual) faculties of cognition, of
feeling, and of appetition; or sensibility (the capacity for receiving
representations through the way in which we are affected by objects),
understanding (the faculty of producing representations spontaneously and
of connecting them); the sensuous feelings of pleasure and pain, taste;
desire, and will. The understanding in the wide sense is equivalent to the
higher faculty of cognition, and divides further into understanding in the
stricter sense (faculty of concepts), judgment (faculty of judging), and
reason (faculty of inference). Of these the first gives laws to the faculty
of cognition or to nature, the second laws to taste, and the third laws to
the will.
The most important of the fundamental assumptions concerns the relation,
the nature, and the mission of the two faculties of cognition. These do
not differ in degree, through the possession of greater or less
distinctness--for there are sensuous representations which are distinct and
intellectual ones which are not so--but specifically: Sensibility is the
faculty of intuitions, understanding the faculty of concepts. Intuitions
are particular, concepts general representations. The former relate to
objects directly, the latter only indirectly (through the mediation of
other representations). In intuition the mind is receptive, in conception
it acts spontaneously. "Through intuitions objects are _given_ to us;
through concepts they are _thought_." It results from this that neither of
the two faculties is of itself sufficient for the attainment of knowledge,
for cognition is objective thinking, the determination of objects, the
unifying combination or elaboration of a given manifold, the forming of a
material content. Rationalists and empiricists alike have been deceived
in regard to the necessity for co-operation between the senses and the
understanding. Sensibility furnishes the material manifold, which of itself
it is not able to form, while the understanding gives the unifying form, to
which of itself it cannot furnish a content. "Intuitions without concepts
are _blind_" (formless, unintelligible), "concepts without intuitions are
_empty_" (without content). In the one case, form and order are wanting; in
the other, the material to be formed. The two faculties are thrown back on
each other, and knowledge can arise only from their union.
A certain degree of form is attained in sense, it is true, since the chaos
of sensations is ordered under the "forms of intuition," space and time,
which are an original possession of the intuiting subject, but this is
not sufficient, without the aid of the understanding, for the genesis of
knowledge. In view of the _a priori_ nature of space and time, though
without detraction from their intuitive character (they are immediate
particular representations), we may assign pure sensibility to the higher
faculty of cognition and speak of an intuiting reason.
The forms of intuition and of thought come from within, they lie ready in
the mind _a priori_, though not as completed representations. They are
functions, necessary actions of the soul, for the execution of which a
stimulus from without, through sensations, is necessary, but which, when
once this is given, the soul brings forth spontaneously. The external
impulse merely gives the soul the occasion for such productive acts, while
their grounds and laws are found in its own nature. In this sense Kant
terms them "originally acquired," and in the Introduction to the _Critique
of Pure Reason_ declares that although it is indubitable that "all our
knowledge begins _with_ experience (impressions of sense), yet it does not
all arise _from_ experience." That a representation or cognition is _a
priori_[1] does not mean that it precedes experience in time, but that
(apart from the merely exciting, non-productive stimulation through
impressions already mentioned) it is independent of all experience, that it
is not derived or borrowed from experience.
[Footnote 1: The terms _a priori_ representation and pure representation
(concept, intuition) are equivalent; but in judgments, on the other hand,
there is a distinction. A judgment is _a priori_ when the connection takes
place independently of experience, no matter whether the concepts connected
are _a priori_ or not. If the former is the case the _a priori_ judgment is
pure (mixed with nothing empirical); if the latter, it is mixed.]
The material of intuition and thought is given to the soul, received by
it; it arises through the action of objects upon the senses, and is always
empirical. Intuition is the only organ of reality; in sensation the
presence of a real object as the cause of the sensation is directly
revealed. When Kant's transcendental idealism was placed by a reviewer on a
level with the empirical idealism of Berkeley, which denies the existence
of the external world, he distinctly asserted that it had never entered
his mind to question the reality of external things. Further, after the
existence of real things affecting the senses had been transformed in
his mind from a basis of the investigation into an object of inquiry,
he endeavored to defend this assumption (which at first he had naïvely
borrowed from the realism of pre-scientific thought) by arguments, but
without any satisfactory result.[1]
[Footnote 1: The task of confirming the existence of things in themselves
changes under his hands into another, that of proving the existence of
external phenomena. "That external objects are real as representations"
Berkeley had never disputed.]
On the basis of the inseparability of sensibility and understanding the
ideal of knowledge--an extension of knowledge to be attained by _a priori_
means (p. 333)--experiences a remarkable addition in the position that the
rational synthesis thus obtained must be a knowledge of reality, must be
applied to matter given in intuition. To the question, "How are synthetic
judgments _a priori possible_?" is joined a second equally legitimate
inquiry, "How do they become _objectively valid_, or applicable to objects
of experience?" The principle from which their validity is proved--they are
applicable to objects of experience because _without them experience would
not be possible_, because they are _conditions of experience_--like the
criterion of apriority (strict universality and necessity), is one of the
noëtic assumptions of the critical theory.[1]
[Footnote 1: Cf. Vaihinger, _Kommentar_, i. pp. 425-430.]
Inasmuch as its investigation relates to the conditions of experience the
Kantian criticism follows a method which it itself terms _transcendental_.
Heretofore, when the metaphysical method had been adopted, the object had
been the suprasensible; and when knowledge had been made the object of
investigation, the method followed had been empirical, psychological. Kant
had the right to consider himself the creator of noëtics, for he showed it
the transcendental point of view. Knowledge is an object of experience, but
its conditions are not. The object is to explain knowledge, not merely to
describe it psychologically,--to establish a new science of knowledge from
principles, from pure reason. That which lies beyond experience is
sealed from our thought; that which lies on this side of it is still
uninvestigated, though capable and worthy of investigation, and in
extreme need thereof. Criticism forbids the _transcendent_ use of reason
(transcending experience); it permits, demands, and itself exercises the
_transcendental_[1] use of it, which explains an experiential object,
knowledge, from its conditions, which are not empirically given.
[Footnote A: Kant applies the term _transcendental_ to the knowledge (the
discovery, the proof) of the _a priori_ factor and its relation to objects
of experience. Unfortunately he often uses the same word not only to
designate the _a priori_ element itself, but also as a synonym for
transcendent. In all three cases its opposite is _empirical_, namely,
empirico-psychological investigation by observation in distinction from
noëtical investigation from principles; empirical origin in distinction
from an origin in pure reason, and empirical use in distinction from
application beyond the limits of experience.]
There is, apparently, a contradiction between the empiristic result of the
Critique of Reason (the limitation of knowledge to objects of experience)
and its rationalistic proofs (which proceed metaphysically, not
empirically), and, in fact, a considerable degree of opposition really
exists. Kant argues in a metaphysical way that there can be no metaphysics.
This contradiction is solved by the distinction which has been mentioned
between that which is beyond, and that which lies within, the boundary of
experience. That metaphysic is forbidden which on the objective side soars
beyond experience, but that pure rational knowledge is permissible and
necessary which develops from principles the grounds of experiential
knowledge existing in the subject. In the Kantian school, however, these
complementary elements,--empirical result, transcendental or metaphysical,
properly speaking, pro-physical method,--were divorced, and the one
emphasized, favored, and further developed at the expense of the other.
The empiricists hold to the result, while they either weaken or completely
misunderstand the rationalism of the method: the _a priori_ factor, says
Fries, was not reached by _a priori_, but by _a posteriori_, means, and
there is no other way by which it could have been reached. The constructive
thinkers, Fichte and his successors, adopt and continue the metaphysical
method, but reject the empirical result. Fichte's aim is directed to
a system of necessary, unconscious processes of reason, among which,
rejecting the thing in itself, he includes sensation. According to
Schelling nature itself is _a priori_, a condition of consciousness. This
discrepancy between foundation and result continues in an altered form even
among contemporary thinkers--as a discussion whether the "main purpose"
of Criticism is to be found in the limitation of knowledge to possible
experience, or the establishment of _a priori_ elements--though many, in
adherence to Kant's own view, maintain that the metaphysics of knowledge
and of phenomena (immanent rationalism) is the only legitimate metaphysics.
%1. Theory of Knowledge.
(a) The Pure Intuitions (Transcendental Aesthetic).%--The first part of the
Critique of Reason, the Transcendental Aesthetic, lays down the position
that _space and time_ are not independent existences, not real beings, and
not properties or relations which would belong to things in themselves
though they were not intuited, but _forms of our intuition_, which have
their basis in the subjective constitution of our, the human, mind. If we
separate from sensuous intuition all that the understanding thinks in it
through its concepts, and all that belongs to sensation, these two forms of
intuition remain, which may be termed pure intuitions, since they can be
considered apart from all sensation. As subjective _conditions_ (lying in
the nature of the subject) through which alone a thing can become an object
of intuition for us, they precede all empirical intuitions or are
_a priori_.
Space and time are neither substantial receptacles which contain all
that is real nor orders inhering in things in themselves, but forms of
intuition. Now all our representations are either pure or empirical in
their origin, and either intuitive or conceptual in character. Kant
advances four proofs for the position that space and time are not empirical
and not concepts, but pure intuitions: (1) Time is not an empirical
concept which has been abstracted from experience. For the coexistence or
succession of phenomena, _i.e._, their existence at the same time or at
different times (from which, as many believe, the representation of time
is abstracted), itself presupposes time--a coexistence or succession is
possible only in time. It is no less false that space is abstracted from
the empirical space relations of external phenomena, their existence
outside and beside one another, or in different places, for it is
impossible to represent relative situation except in space. Therefore
experience does not make space and time possible; but space and time first
of all make experience possible, the one outer, the other inner experience.
They are postulates of perception, not abstractions from it. (2) Time is a
necessary representation _a priori_. We can easily think all phenomena away
from it, but we cannot remove time itself in view of phenomena in general;
we can think time without phenomena, but not phenomena without time. The
same is true of space in reference to external objects. Both are conditions
of the possibility of phenomena. (3) Time is not a discursive or general
concept. For there is but one time. And different times do not precede the
one time as the constituent parts of which it is made up, but are mere
limitations of it; the part is possible only through the whole. In the same
way the various spaces are only parts of one and the same space, and can
be thought in it alone. But a representation which can be given only by
a single object is a particular representation or an intuition. Because,
therefore, of the oneness of space and time, the representation of each
is an intuition. The _a priori_, immediate intuition of the one space is
entirely different from the empirical, general conception of space, which
is abstracted from the various spaces. (4) Determinate periods of time
arise by limitation of the one, fundamental time. Consequently this
original time must be unlimited or infinite, and the representation of it
must be an intuition, not a concept. Time contains in itself an endless
number of representations (its parts, times), but this is never the
case with a generic concept, which, indeed, is contained as a partial
representation in an endless number of representations (those of the
individuals having the same name), and, consequently, comprehends them all
under itself, but which never contains them in itself. The general concept
horse is contained in each particular representation of a horse as a
general characteristic, and that of justice in each representation of a
definite just act; time, however, is not contained in the different times,
but they are contained in it. Similarly the relation of infinite space to
the finite spaces is not the logical relation of a concept to examples of
it, but the intuitive relation of an unlimited whole to its limited parts.
The _Prolegomena_ employs as a fifth proof for the intuitive character of
space, an argument which had already appeared in the essay _On the Ultimate
Ground of the Distinction of Positions in Space_. There are certain spatial
distinctions which can be grasped by intuition alone, and which are
absolutely incapable of comprehension through the understanding--for
example, those of right and left, above and below, before and behind. No
logical marks can be given for the distinction between the object and its
image in the mirror, or between the right ear and the left. The complete
description of a right hand must, in all respects (quality, proportionate
position of parts, size of the whole), hold for the left as well;
but, despite the complete similarity, the one hand cannot be exactly
super-imposed on the other; the glove of the one cannot be worn on the
other. This difference in direction, which has significance only when
viewed from a definite point, and the impossibility mentioned of a
congruence between an object (right hand) and its reflected image (left
hand) can be understood only by intuition; they must be seen and felt, and
cannot be made clear through concepts, and, consequently, can never be
explained to a being which lacks the intuition of space.
In the "transcendental" exposition of space and time Kant follows this
"metaphysical" exposition, which had to prove their non-empirical, and
non-discursive, hence their _a priori_ and intuitive, character, with
the proof that only such an explanation of space and time could make it
conceivable how synthetic cognitions _a priori_ can arise from them. The
principles of mathematics are of this kind. The synthetic character of
geometrical truths is explained by the intuitive nature of space, their
apodictic character by its apriority, and their objective reality or
applicability to empirical objects by the fact that space is the condition
of (external) perception. The like is true of arithmetic and time.
If space were a mere concept, no proposition could be derived from it which
should go beyond the concept and extend our knowledge of its properties.
The possibility of such extension or synthesis in mathematics depends on
the fact that spatial concepts can always be presented or "constructed" in
intuition. The geometrical axiom that in the triangle the sum of two sides
is greater than the third is derived from intuition, by describing the
triangle in imagination or, actually, on the board. Here the object is
given through the cognition and not before it.--If space and time were
empirical representations the knowledge obtained from them would lack
necessity, which, as a matter of fact, it possesses in a marked degree.
While experience teaches us only that something is thus or so, and not that
it could not be otherwise, the axioms, (space has only three dimensions,
time only one; only one straight line is possible between two points),
nay, all the propositions of mathematics are strictly universal and
apodictically certain: we are entirely relieved from the necessity of
measuring all triangles in the world in order to find out whether the sum
of their angles is equal to two right angles, and we do not need, as in the
case of judgments of experience, to add the limitation, so far as it is yet
known there are no exceptions to this rule. The apriority is the _ratio
essendi_ of the strict necessity involved in the "it must be so" _(des
Soseinmüssens_), while the latter is the _ratio cognoscendi_ of the former.
Now since the necessity of mathematical judgments can only be explained
through the ideality of space, this doctrine is perfectly certain, not
merely a probable hypothesis.--The validity of mathematical principles for
all objects of perception, finally, is based on the fact that they are
rules under which alone experience is possible for us. It should be
mentioned, further, that the conceptions of change and motion (change of
place) are possible only through and in the representation of time. No
concept could make intelligible the possibility of change, that is, of the
connection of contradictory predicates in one and the same thing, but the
intuition of succession easily succeeds in accomplishing it.
The argument is followed by conclusions and explanations based upon it;
(1) Space is the form of the outer, time of the inner, sense. Through the
outer sense external objects are given to us, and through the inner sense
our own inner states. But since all representations, whether they have
external things for their objects or not, belong in themselves, as mental
determinations, to our inner state, time is the formal condition of all
phenomena in general, directly of internal (psychical) phenomena, and,
thereby, indirectly of external phenomena also. (2) The validity of the
relations of space and time cognizable _a priori_ is established for all
objects of possible experience, but is limited to these. They are valid
for _all phenomena_ (for all things which at any time may be given to our
senses), but only for these, not for things as they are _in themselves_.
They have "empirical reality, but, at the same time, transcendental
ideality." As external phenomena all things are beside one another in
space, and all phenomena whatever are in time and of necessity under
temporal relations; in regard to all things which can occur in our
experience, and in so far as they can occur, space and time are
objectively, therefore empirically, real. But they do not possess absolute
reality (neither subsistent reality nor the reality of inherence); for if
we abstract from our sensuous intuition both vanish, and, apart from the
subject (_N.B._, the transcendental subject, concerning which more below),
they are naught. It is only from man's point of view that we can speak
of space, and of extended, moveable, changeable things; for we can know
nothing concerning the intuitions of other thinking beings, we have no
means of discovering whether they are bound by the same conditions which
limit our intuitions, and which for us are universally valid. (3) Nothing
which is intuited in space is a thing in itself. What we call external
objects are nothing but mere representations of our sensibility, whose
true correlative, the _thing in itself_, cannot be known by ever so deep
penetration into the phenomenon; such properties as belong to things in
themselves can never be given to us through the senses. Similarly nothing
that is intuited in time is a thing in itself, so that we intuit ourselves
only as we appear to ourselves, and not as we are.
The merely empirical reality of space and time, the limitation of their
validity to phenomena, leaves the certainty of knowledge within the limits
of experience intact; for we are equally certain of it, whether these forms
necessarily belong to things in themselves, or only to our intuitions
of things. The assertion of their absolute reality, on the other hand,
involves us in sheer absurdities (that is, it necessitates the assumption
of two infinite nonentities which exist, but without being anything real,
merely in order to comprehend all reality, and on one of which even our own
existence would be dependent), in view of which the origin of so peculiar
a theory as the idealism of Berkeley appears intelligible. The critical
theory of space and time is so far from being identical with, or akin to,
the theory of Berkeley, that it furnishes the best and only defense against
the latter. If anyone assumes the absolute or transcendental reality of
these forms, it is impossible for him to prevent everything, including even
our own existence, from being changed thereby into mere illusion. But
the critical philosopher is far from degrading bodies to mere illusion;
external phenomena are just as real for him as internal phenomena, though
only as phenomena, it is true, as (possible) representations.
Phenomenon and illusion are not the same. The transcendental distinction
between phenomena and things in themselves must not be confused with the
distinction common to ordinary life and to physics, in accordance with
which we call the rainbow a mere appearance (better, illusion), but the
combination of sun and rain which gives rise to this illusion the thing
in itself, as that which in universal experience and in all different
positions with respect to the senses, is thus and not otherwise determined
in intuition, or that which essentially belongs to the intuition of the
object, and is valid for every human sensibility (in antithesis to that
which only contingently belongs to it, and is valid only for a special
position or organization of this or that sense). Similarly an object always
appears to grow smaller as its distance increases, while in itself it is
and remains of some fixed size. And this use of words is perfectly
correct, in the _physical or empirical_ sense of "in itself"; but in the
_transcendental_ sense the raindrops, also, together with their form and
size, are themselves mere phenomena, the "in itself" of which remains
entirely unknown to us. Kant, moreover, does not wish to see the
subjectivity of the forms of intuition placed on a level with the
subjectivity of sensations or explained by this, though he accepts it as
a fact long established. The sensations of color, of tone, of temperature
are, no doubt, like the representation of space in that they belong only to
the subjective constitution of the sensibility, and can be attributed to
objects only in relation to our senses. But the great difference between
the two is that these sense qualities may be different in different persons
(the color of the rose may seem different to each eye), or may fail to
harmonize with any human sense; that they are not _a priori_ in the same
strict sense as space and time, and consequently afford no knowledge of the
objects of possible experience independently of perception; and that they
are connected with the phenomenon only as the contingently added effects of
a particular organization, while space, as the condition of external
objects, necessarily belongs to the phenomenon or intuition of them. _It is
through space alone that it is possible for things to be external objects
for us_. The subjectivity of sensation is individual, while that of space
and time is general or universal to mankind; the former is empirical,
individually different, and contingent, the latter _a priori_ and
necessary. Space alone, not sensation, is a _conditio sine qua non_ of
external perception. Space and time are the sole _a priori_ elements of
the sensibility; all other sensuous concepts, even motion and change,
presuppose perception; the movable in space and the succession of
properties in an existing thing are empirical data.
In confirmation of the theory that all objects of the senses are mere
phenomena, the fact is adduced that (with the exception of the will and the
feelings, which are not cognitions) nothing is given us through the senses
but representations of relations, while a thing in itself cannot be known
by mere relations. The phenomenon is a sum total of mere relations. In
regard to matter we know only extension, motion, and the laws of this
motion or forces (attraction, repulsion, impenetrability), but all these
are merely relations of the thing to something, else, that is, external
relations. Where is the inner side which underlies this exterior, and
which belongs to the object in itself? This is never to be found in the
phenomenon, and no matter how far the observation and analysis of nature
may advance (a work with unlimited horizons!) they reach nothing but
portions of space occupied by matter and effects which matter exercises,
that is, nothing beyond that which is comparatively internal, and which,
in its turn, consists of external relations. The absolutely inner side
of matter is a mere fancy; and if the complaint that the "inner side" of
things is concealed from us is to mean that we do not comprehend what
the things which appear to us may be in themselves, it is unjust and
irrational, for it demands that we should be able to intuit without
senses, in other words, that we should be other than men. The transcendent
questions concerning the noumenon of things are unanswerable; we know
ourselves, even, only as phenomena! A phenomenon consists in nothing but
the relation of something in general to the senses.
It is indubitable _that_ something corresponds to phenomena, which,
by affecting our sensibility, occasions sensations in us, and thereby
phenomena. The very word, the very concept, "phenomenon", indicates a
relation to something which is not phenomenon, to an object not dependent
on the sensibility. _What_ this may be continues hidden from us, for
knowledge is impossible without intuition. Things in themselves are
unknowable. Nevertheless the idea (it must be confessed, the entirely empty
idea) of this "transcendental object", as an indeterminate somewhat = _x_
which underlies phenomena, is not only allowable, but, as a limiting
concept, unavoidable in order to confine the pretensions of sense to the
only field which is accessible to it, that is, to the field of phenomena.
The inference "space and time are nothing but representations and
representations are in us, therefore space and time as well as all
phenomena in them, bodies with their forces and motions, are in us," does
not accurately express Kant's position, for he might justly reply that,
according to him, bodies as phenomena are in different parts in space from
that which we assign to ourselves, and thus without us; that space is the
form of external intuition, and through it external objects arise for us
from sensations; but that, in regard to the things in themselves which
affect us, we are entirely ignorant whether they are within or without us.