the universe. For nature is properly the only object presented to us,
in regard to which reason requires regulative principles. Nature is
twofold—thinking and corporeal nature. To cogitate the latter in regard
to its internal possibility, that is, to determine the application of
the categories to it, no idea is required—no representation which
transcends experience. In this sphere, therefore, an idea is
impossible, sensuous intuition being our only guide; while, in the
sphere of psychology, we require the fundamental idea (I), which
contains à priori a certain form of thought namely, the unity of the
ego. Pure reason has, therefore, nothing left but nature in general,
and the completeness of conditions in nature in accordance with some
principle. The absolute totality of the series of these conditions is
an idea, which can never be fully realized in the empirical exercise of
reason, while it is serviceable as a rule for the procedure of reason
in relation to that totality. It requires us, in the explanation of
given phenomena (in the regress or ascent in the series), to proceed as
if the series were infinite in itself, that is, were prolonged in
indefinitum; while on the other hand, where reason is regarded as
itself the determining cause (in the region of freedom), we are
required to proceed as if we had not before us an object of sense, but
of the pure understanding. In this latter case, the conditions do not
exist in the series of phenomena, but may be placed quite out of and
beyond it, and the series of conditions may be regarded as if it had an
absolute beginning from an intelligible cause. All this proves that the
cosmological ideas are nothing but regulative principles, and not
constitutive; and that their aim is not to realize an actual totality
in such series. The full discussion of this subject will be found in
its proper place in the chapter on the antinomy of pure reason.
The third idea of pure reason, containing the hypothesis of a being
which is valid merely as a relative hypothesis, is that of the one and
all-sufficient cause of all cosmological series, in other words, the
idea of God. We have not the slightest ground absolutely to admit the
existence of an object corresponding to this idea; for what can empower
or authorize us to affirm the existence of a being of the highest
perfection—a being whose existence is absolutely necessary—merely
because we possess the conception of such a being? The answer is: It is
the existence of the world which renders this hypothesis necessary. But
this answer makes it perfectly evident that the idea of this being,
like all other speculative ideas, is essentially nothing more than a
demand upon reason that it shall regulate the connection which it and
its subordinate faculties introduce into the phenomena of the world by
principles of systematic unity and, consequently, that it shall regard
all phenomena as originating from one all-embracing being, as the
supreme and all-sufficient cause. From this it is plain that the only
aim of reason in this procedure is the establishment of its own formal
rule for the extension of its dominion in the world of experience; that
it does not aim at an extension of its cognition beyond the limits of
experience; and that, consequently, this idea does not contain any
constitutive principle.
The highest formal unity, which is based upon ideas alone, is the unity
of all things—a unity in accordance with an aim or purpose; and the
speculative interest of reason renders it necessary to regard all order
in the world as if it originated from the intention and design of a
supreme reason. This principle unfolds to the view of reason in the
sphere of experience new and enlarged prospects, and invites it to
connect the phenomena of the world according to teleological laws, and
in this way to attain to the highest possible degree of systematic
unity. The hypothesis of a supreme intelligence, as the sole cause of
the universe—an intelligence which has for us no more than an ideal
existence—is accordingly always of the greatest service to reason.
Thus, if we presuppose, in relation to the figure of the earth (which
is round, but somewhat flattened at the poles),[71] or that of
mountains or seas, wise designs on the part of an author of the
universe, we cannot fail to make, by the light of this supposition, a
great number of interesting discoveries. If we keep to this hypothesis,
as a principle which is purely regulative, even error cannot be very
detrimental. For, in this case, error can have no more serious
consequences than that, where we expected to discover a teleological
connection (nexus finalis), only a mechanical or physical connection
appears. In such a case, we merely fail to find the additional form of
unity we expected, but we do not lose the rational unity which the mind
requires in its procedure in experience. But even a miscarriage of this
sort cannot affect the law in its general and teleological relations.
For although we may convict an anatomist of an error, when he connects
the limb of some animal with a certain purpose, it is quite impossible
to prove in a single case that any arrangement of nature, be it what it
may, is entirely without aim or design. And thus medical physiology, by
the aid of a principle presented to it by pure reason, extends its very
limited empirical knowledge of the purposes of the different parts of
an organized body so far that it may be asserted with the utmost
confidence, and with the approbation of all reflecting men, that every
organ or bodily part of an animal has its use and answers a certain
design. Now, this is a supposition which, if regarded as of a
constitutive character, goes much farther than any experience or
observation of ours can justify. Hence it is evident that it is nothing
more than a regulative principle of reason, which aims at the highest
degree of systematic unity, by the aid of the idea of a causality
according to design in a supreme cause—a cause which it regards as the
highest intelligence.
[71] The advantages which a circular form, in the case of the earth,
has over every other, are well known. But few are aware that the
slight flattening at the poles, which gives it the figure of a
spheroid, is the only cause which prevents the elevations of
continents or even of mountains, perhaps thrown up by some internal
convulsion, from continually altering the position of the axis of the
earth—and that to some considerable degree in a short time. The great
protuberance of the earth under the Equator serves to overbalance the
impetus of all other masses of earth, and thus to preserve the axis of
the earth, so far as we can observe, in its present position. And yet
this wise arrangement has been unthinkingly explained from the
equilibrium of the formerly fluid mass.
If, however, we neglect this restriction of the idea to a purely
regulative influence, reason is betrayed into numerous errors. For it
has then left the ground of experience, in which alone are to be found
the criteria of truth, and has ventured into the region of the
incomprehensible and unsearchable, on the heights of which it loses its
power and collectedness, because it has completely severed its
connection with experience.
The first error which arises from our employing the idea of a Supreme
Being as a constitutive (in repugnance to the very nature of an idea),
and not as a regulative principle, is the error of inactive reason
(ignava ratio).[72] We may so term every principle which requires us to
regard our investigations of nature as absolutely complete, and allows
reason to cease its inquiries, as if it had fully executed its task.
Thus the psychological idea of the ego, when employed as a constitutive
principle for the explanation of the phenomena of the soul, and for the
extension of our knowledge regarding this subject beyond the limits of
experience—even to the condition of the soul after death—is convenient
enough for the purposes of pure reason, but detrimental and even
ruinous to its interests in the sphere of nature and experience. The
dogmatizing spiritualist explains the unchanging unity of our
personality through all changes of condition from the unity of a
thinking substance, the interest which we take in things and events
that can happen only after our death, from a consciousness of the
immaterial nature of our thinking subject, and so on. Thus he dispenses
with all empirical investigations into the cause of these internal
phenomena, and with all possible explanations of them upon purely
natural grounds; while, at the dictation of a transcendent reason, he
passes by the immanent sources of cognition in experience, greatly to
his own ease and convenience, but to the sacrifice of all, genuine
insight and intelligence. These prejudicial consequences become still
more evident, in the case of the dogmatical treatment of our idea of a
Supreme Intelligence, and the theological system of nature
(physico-theology) which is falsely based upon it. For, in this case,
the aims which we observe in nature, and often those which we merely
fancy to exist, make the investigation of causes a very easy task, by
directing us to refer such and such phenomena immediately to the
unsearchable will and counsel of the Supreme Wisdom, while we ought to
investigate their causes in the general laws of the mechanism of
matter. We are thus recommended to consider the labour of reason as
ended, when we have merely dispensed with its employment, which is
guided surely and safely only by the order of nature and the series of
changes in the world—which are arranged according to immanent and
general laws. This error may be avoided, if we do not merely consider
from the view-point of final aims certain parts of nature, such as the
division and structure of a continent, the constitution and direction
of certain mountain-chains, or even the organization existing in the
vegetable and animal kingdoms, but look upon this systematic unity of
nature in a perfectly general way, in relation to the idea of a Supreme
Intelligence. If we pursue this advice, we lay as a foundation for all
investigation the conformity to aims of all phenomena of nature in
accordance with universal laws, for which no particular arrangement of
nature is exempt, but only cognized by us with more or less difficulty;
and we possess a regulative principle of the systematic unity of a
teleological connection, which we do not attempt to anticipate or
predetermine. All that we do, and ought to do, is to follow out the
physico-mechanical connection in nature according to general laws, with
the hope of discovering, sooner or later, the teleological connection
also. Thus, and thus only, can the principle of final unity aid in the
extension of the employment of reason in the sphere of experience,
without being in any case detrimental to its interests.
[72] This was the term applied by the old dialecticians to a
sophistical argument, which ran thus: If it is your fate to die of
this disease, you will die, whether you employ a physician or not.
Cicero says that this mode of reasoning has received this appellation,
because, if followed, it puts an end to the employment of reason in
the affairs of life. For a similar reason, I have applied this
designation to the sophistical argument of pure reason.
The second error which arises from the misconception of the principle
of systematic unity is that of perverted reason (perversa ratio,
usteron roteron rationis). The idea of systematic unity is available as
a regulative principle in the connection of phenomena according to
general natural laws; and, how far soever we have to travel upon the
path of experience to discover some fact or event, this idea requires
us to believe that we have approached all the more nearly to the
completion of its use in the sphere of nature, although that completion
can never be attained. But this error reverses the procedure of reason.
We begin by hypostatizing the principle of systematic unity, and by
giving an anthropomorphic determination to the conception of a Supreme
Intelligence, and then proceed forcibly to impose aims upon nature.
Thus not only does teleology, which ought to aid in the completion of
unity in accordance with general laws, operate to the destruction of
its influence, but it hinders reason from attaining its proper aim,
that is, the proof, upon natural grounds, of the existence of a supreme
intelligent cause. For, if we cannot presuppose supreme finality in
nature à priori, that is, as essentially belonging to nature, how can
we be directed to endeavour to discover this unity and, rising
gradually through its different degrees, to approach the supreme
perfection of an author of all—a perfection which is absolutely
necessary, and therefore cognizable à priori? The regulative principle
directs us to presuppose systematic unity absolutely and, consequently,
as following from the essential nature of things—but only as a unity of
nature, not merely cognized empirically, but presupposed à priori,
although only in an indeterminate manner. But if I insist on basing
nature upon the foundation of a supreme ordaining Being, the unity of
nature is in effect lost. For, in this case, it is quite foreign and
unessential to the nature of things, and cannot be cognized from the
general laws of nature. And thus arises a vicious circular argument,
what ought to have been proved having been presupposed.
To take the regulative principle of systematic unity in nature for a
constitutive principle, and to hypostatize and make a cause out of that
which is properly the ideal ground of the consistent and harmonious
exercise of reason, involves reason in inextricable embarrassments. The
investigation of nature pursues its own path under the guidance of the
chain of natural causes, in accordance with the general laws of nature,
and ever follows the light of the idea of an author of the universe—not
for the purpose of deducing the finality, which it constantly pursues,
from this Supreme Being, but to attain to the cognition of his
existence from the finality which it seeks in the existence of the
phenomena of nature, and, if possible, in that of all things to cognize
this being, consequently, as absolutely necessary. Whether this latter
purpose succeed or not, the idea is and must always be a true one, and
its employment, when merely regulative, must always be accompanied by
truthful and beneficial results.
Complete unity, in conformity with aims, constitutes absolute
perfection. But if we do not find this unity in the nature of the
things which go to constitute the world of experience, that is, of
objective cognition, consequently in the universal and necessary laws
of nature, how can we infer from this unity the idea of the supreme and
absolutely necessary perfection of a primal being, which is the origin
of all causality? The greatest systematic unity, and consequently
teleological unity, constitutes the very foundation of the possibility
of the most extended employment of human reason. The idea of unity is
therefore essentially and indissolubly connected with the nature of our
reason. This idea is a legislative one; and hence it is very natural
that we should assume the existence of a legislative reason
corresponding to it, from which the systematic unity of nature—the
object of the operations of reason—must be derived.
In the course of our discussion of the antinomies, we stated that it is
always possible to answer all the questions which pure reason may
raise; and that the plea of the limited nature of our cognition, which
is unavoidable and proper in many questions regarding natural
phenomena, cannot in this case be admitted, because the questions
raised do not relate to the nature of things, but are necessarily
originated by the nature of reason itself, and relate to its own
internal constitution. We can now establish this assertion, which at
first sight appeared so rash, in relation to the two questions in which
reason takes the greatest interest, and thus complete our discussion of
the dialectic of pure reason.
If, then, the question is asked, in relation to transcendental
theology,[73] first, whether there is anything distinct from the world,
which contains the ground of cosmical order and connection according to
general laws? The answer is: Certainly. For the world is a sum of
phenomena; there must, therefore, be some transcendental basis of these
phenomena, that is, a basis cogitable by the pure understanding alone.
If, secondly, the question is asked whether this being is substance,
whether it is of the greatest reality, whether it is necessary, and so
forth? I answer that this question is utterly without meaning. For all
the categories which aid me in forming a conception of an object cannot
be employed except in the world of sense, and are without meaning when
not applied to objects of actual or possible experience. Out of this
sphere, they are not properly conceptions, but the mere marks or
indices of conceptions, which we may admit, although they cannot,
without the help of experience, help us to understand any subject or
thing. If, thirdly, the question is whether we may not cogitate this
being, which is distinct from the world, in analogy with the objects of
experience? The answer is: Undoubtedly, but only as an ideal, and not
as a real object. That is, we must cogitate it only as an unknown
substratum of the systematic unity, order, and finality of the world—a
unity which reason must employ as the regulative principle of its
investigation of nature. Nay, more, we may admit into the idea certain
anthropomorphic elements, which are promotive of the interests of this
regulative principle. For it is no more than an idea, which does not
relate directly to a being distinct from the world, but to the
regulative principle of the systematic unity of the world, by means,
however, of a schema of this unity—the schema of a Supreme
Intelligence, who is the wisely-designing author of the universe. What
this basis of cosmical unity may be in itself, we know not—we cannot
discover from the idea; we merely know how we ought to employ the idea
of this unity, in relation to the systematic operation of reason in the
sphere of experience.
[73] After what has been said of the psychological idea of the ego and
its proper employment as a regulative principle of the operations of
reason, I need not enter into details regarding the transcendental
illusion by which the systematic unity of all the various phenomena of
the internal sense is hypostatized. The procedure is in this case very
similar to that which has been discussed in our remarks on the
theological ideal.
But, it will be asked again, can we on these grounds, admit the
existence of a wise and omnipotent author of the world? Without doubt;
and not only so, but we must assume the existence of such a being. But
do we thus extend the limits of our knowledge beyond the field of
possible experience? By no means. For we have merely presupposed a
something, of which we have no conception, which we do not know as it
is in itself; but, in relation to the systematic disposition of the
universe, which we must presuppose in all our observation of nature, we
have cogitated this unknown being in analogy with an intelligent
existence (an empirical conception), that is to say, we have endowed it
with those attributes, which, judging from the nature of our own
reason, may contain the ground of such a systematic unity. This idea is
therefore valid only relatively to the employment in experience of our
reason. But if we attribute to it absolute and objective validity, we
overlook the fact that it is merely an ideal being that we cogitate;
and, by setting out from a basis which is not determinable by
considerations drawn from experience, we place ourselves in a position
which incapacitates us from applying this principle to the empirical
employment of reason.
But, it will be asked further, can I make any use of this conception
and hypothesis in my investigations into the world and nature? Yes, for
this very purpose was the idea established by reason as a fundamental
basis. But may I regard certain arrangements, which seemed to have been
made in conformity with some fixed aim, as the arrangements of design,
and look upon them as proceeding from the divine will, with the
intervention, however, of certain other particular arrangements
disposed to that end? Yes, you may do so; but at the same time you must
regard it as indifferent, whether it is asserted that divine wisdom has
disposed all things in conformity with his highest aims, or that the
idea of supreme wisdom is a regulative principle in the investigation
of nature, and at the same time a principle of the systematic unity of
nature according to general laws, even in those cases where we are
unable to discover that unity. In other words, it must be perfectly
indifferent to you whether you say, when you have discovered this
unity: God has wisely willed it so; or: Nature has wisely arranged
this. For it was nothing but the systematic unity, which reason
requires as a basis for the investigation of nature, that justified you
in accepting the idea of a supreme intelligence as a schema for a
regulative principle; and, the farther you advance in the discovery of
design and finality, the more certain the validity of your idea. But,
as the whole aim of this regulative principle was the discovery of a
necessary and systematic unity in nature, we have, in so far as we
attain this, to attribute our success to the idea of a Supreme Being;
while, at the same time, we cannot, without involving ourselves in
contradictions, overlook the general laws of nature, as it was in
reference to them alone that this idea was employed. We cannot, I say,
overlook the general laws of nature, and regard this conformity to aims
observable in nature as contingent or hyperphysical in its origin;
inasmuch as there is no ground which can justify us in the admission of
a being with such properties distinct from and above nature. All that
we are authorized to assert is that this idea may be employed as a
principle, and that the properties of the being which is assumed to
correspond to it may be regarded as systematically connected in analogy
with the causal determination of phenomena.
For the same reasons we are justified in introducing into the idea of
the supreme cause other anthropomorphic elements (for without these we
could not predicate anything of it); we may regard it as allowable to
cogitate this cause as a being with understanding, the feelings of
pleasure and displeasure, and faculties of desire and will
corresponding to these. At the same time, we may attribute to this
being infinite perfection—a perfection which necessarily transcends
that which our knowledge of the order and design in the world authorize
us to predicate of it. For the regulative law of systematic unity
requires us to study nature on the supposition that systematic and
final unity in infinitum is everywhere discoverable, even in the
highest diversity. For, although we may discover little of this
cosmical perfection, it belongs to the legislative prerogative of
reason to require us always to seek for and to expect it; while it must
always be beneficial to institute all inquiries into nature in
accordance with this principle. But it is evident that, by this idea of
a supreme author of all, which I place as the foundation of all
inquiries into nature, I do not mean to assert the existence of such a
being, or that I have any knowledge of its existence; and,
consequently, I do not really deduce anything from the existence of
this being, but merely from its idea, that is to say, from the nature
of things in this world, in accordance with this idea. A certain dim
consciousness of the true use of this idea seems to have dictated to
the philosophers of all times the moderate language used by them
regarding the cause of the world. We find them employing the
expressions wisdom and care of nature, and divine wisdom, as
synonymous—nay, in purely speculative discussions, preferring the
former, because it does not carry the appearance of greater pretensions
than such as we are entitled to make, and at the same time directs
reason to its proper field of action—nature and her phenomena.
Thus, pure reason, which at first seemed to promise us nothing less
than the extension of our cognition beyond the limits of experience, is
found, when thoroughly examined, to contain nothing but regulative
principles, the virtue and function of which is to introduce into our
cognition a higher degree of unity than the understanding could of
itself. These principles, by placing the goal of all our struggles at
so great a distance, realize for us the most thorough connection
between the different parts of our cognition, and the highest degree of
systematic unity. But, on the other hand, if misunderstood and employed
as constitutive principles of transcendent cognition, they become the
parents of illusions and contradictions, while pretending to introduce
us to new regions of knowledge.
Thus all human cognition begins with intuitions, proceeds from thence
to conceptions, and ends with ideas. Although it possesses, in relation
to all three elements, à priori sources of cognition, which seemed to
transcend the limits of all experience, a thoroughgoing criticism
demonstrates that speculative reason can never, by the aid of these
elements, pass the bounds of possible experience, and that the proper
destination of this highest faculty of cognition is to employ all
methods, and all the principles of these methods, for the purpose of
penetrating into the innermost secrets of nature, by the aid of the
principles of unity (among all kinds of which teleological unity is the
highest), while it ought not to attempt to soar above the sphere of
experience, beyond which there lies nought for us but the void inane.
The critical examination, in our Transcendental Analytic, of all the
propositions which professed to extend cognition beyond the sphere of
experience, completely demonstrated that they can only conduct us to a
possible experience. If we were not distrustful even of the clearest
abstract theorems, if we were not allured by specious and inviting
prospects to escape from the constraining power of their evidence, we
might spare ourselves the laborious examination of all the dialectical
arguments which a transcendent reason adduces in support of its
pretensions; for we should know with the most complete certainty that,
however honest such professions might be, they are null and valueless,
because they relate to a kind of knowledge to which no man can by any
possibility attain. But, as there is no end to discussion, if we cannot
discover the true cause of the illusions by which even the wisest are
deceived, and as the analysis of all our transcendent cognition into
its elements is of itself of no slight value as a psychological study,
while it is a duty incumbent on every philosopher—it was found
necessary to investigate the dialectical procedure of reason in its
primary sources. And as the inferences of which this dialectic is the
parent are not only deceitful, but naturally possess a profound
interest for humanity, it was advisable at the same time, to give a
full account of the momenta of this dialectical procedure, and to
deposit it in the archives of human reason, as a warning to all future
metaphysicians to avoid these causes of speculative error.
II. Transcendental Doctrine of Method
If we regard the sum of the cognition of pure speculative reason as an
edifice, the idea of which, at least, exists in the human mind, it may
be said that we have in the Transcendental Doctrine of Elements
examined the materials and determined to what edifice these belong, and
what its height and stability. We have found, indeed, that, although we
had purposed to build for ourselves a tower which should reach to
Heaven, the supply of materials sufficed merely for a habitation, which
was spacious enough for all terrestrial purposes, and high enough to
enable us to survey the level plain of experience, but that the bold
undertaking designed necessarily failed for want of materials—not to
mention the confusion of tongues, which gave rise to endless disputes
among the labourers on the plan of the edifice, and at last scattered
them over all the world, each to erect a separate building for himself,
according to his own plans and his own inclinations. Our present task
relates not to the materials, but to the plan of an edifice; and, as we
have had sufficient warning not to venture blindly upon a design which
may be found to transcend our natural powers, while, at the same time,
we cannot give up the intention of erecting a secure abode for the
mind, we must proportion our design to the material which is presented
to us, and which is, at the same time, sufficient for all our wants.
I understand, then, by the transcendental doctrine of method, the
determination of the formal conditions of a complete system of pure
reason. We shall accordingly have to treat of the discipline, the
canon, the architectonic, and, finally, the history of pure reason.
This part of our Critique will accomplish, from the transcendental
point of view, what has been usually attempted, but miserably executed,
under the name of practical logic. It has been badly executed, I say,
because general logic, not being limited to any particular kind of
cognition (not even to the pure cognition of the understanding) nor to
any particular objects, it cannot, without borrowing from other
sciences, do more than present merely the titles or signs of possible
methods and the technical expressions, which are employed in the
systematic parts of all sciences; and thus the pupil is made acquainted
with names, the meaning and application of which he is to learn only at
some future time.
Chapter I. The Discipline of Pure Reason
Negative judgements—those which are so not merely as regards their
logical form, but in respect of their content—are not commonly held in
especial respect. They are, on the contrary, regarded as jealous
enemies of our insatiable desire for knowledge; and it almost requires
an apology to induce us to tolerate, much less to prize and to respect
them.
All propositions, indeed, may be logically expressed in a negative
form; but, in relation to the content of our cognition, the peculiar
province of negative judgements is solely to prevent error. For this
reason, too, negative propositions, which are framed for the purpose of
correcting false cognitions where error is absolutely impossible, are
undoubtedly true, but inane and senseless; that is, they are in reality
purposeless and, for this reason, often very ridiculous. Such is the
proposition of the schoolman that Alexander could not have subdued any
countries without an army.
But where the limits of our possible cognition are very much
contracted, the attraction to new fields of knowledge great, the
illusions to which the mind is subject of the most deceptive character,
and the evil consequences of error of no inconsiderable magnitude—the
negative element in knowledge, which is useful only to guard us against
error, is of far more importance than much of that positive instruction
which makes additions to the sum of our knowledge. The restraint which
is employed to repress, and finally to extirpate the constant
inclination to depart from certain rules, is termed discipline. It is
distinguished from culture, which aims at the formation of a certain
degree of skill, without attempting to repress or to destroy any other
mental power, already existing. In the cultivation of a talent, which
has given evidence of an impulse towards self-development, discipline
takes a negative,[74] culture and doctrine a positive, part.
[74] I am well aware that, in the language of the schools, the term
discipline is usually employed as synonymous with instruction. But
there are so many cases in which it is necessary to distinguish the
notion of the former, as a course of corrective training, from that of
the latter, as the communication of knowledge, and the nature of
things itself demands the appropriation of the most suitable
expressions for this distinction, that it is my desire that the former
terms should never be employed in any other than a negative
signification.
That natural dispositions and talents (such as imagination and wit),
which ask a free and unlimited development, require in many respects
the corrective influence of discipline, every one will readily grant.
But it may well appear strange that reason, whose proper duty it is to
prescribe rules of discipline to all the other powers of the mind,
should itself require this corrective. It has, in fact, hitherto
escaped this humiliation, only because, in presence of its magnificent
pretensions and high position, no one could readily suspect it to be
capable of substituting fancies for conceptions, and words for things.
Reason, when employed in the field of experience, does not stand in
need of criticism, because its principles are subjected to the
continual test of empirical observations. Nor is criticism requisite in
the sphere of mathematics, where the conceptions of reason must always
be presented in concreto in pure intuition, and baseless or arbitrary
assertions are discovered without difficulty. But where reason is not
held in a plain track by the influence of empirical or of pure
intuition, that is, when it is employed in the transcendental sphere of
pure conceptions, it stands in great need of discipline, to restrain
its propensity to overstep the limits of possible experience and to
keep it from wandering into error. In fact, the utility of the
philosophy of pure reason is entirely of this negative character.
Particular errors may be corrected by particular animadversions, and
the causes of these errors may be eradicated by criticism. But where we
find, as in the case of pure reason, a complete system of illusions and
fallacies, closely connected with each other and depending upon grand
general principles, there seems to be required a peculiar and negative
code of mental legislation, which, under the denomination of a
discipline, and founded upon the nature of reason and the objects of
its exercise, shall constitute a system of thorough examination and
testing, which no fallacy will be able to withstand or escape from,
under whatever disguise or concealment it may lurk.
But the reader must remark that, in this the second division of our
transcendental Critique the discipline of pure reason is not directed
to the content, but to the method of the cognition of pure reason. The
former task has been completed in the doctrine of elements. But there
is so much similarity in the mode of employing the faculty of reason,
whatever be the object to which it is applied, while, at the same time,
its employment in the transcendental sphere is so essentially different
in kind from every other, that, without the warning negative influence
of a discipline specially directed to that end, the errors are
unavoidable which spring from the unskillful employment of the methods
which are originated by reason but which are out of place in this
sphere.
Section I. The Discipline of Pure Reason in the Sphere of Dogmatism
The science of mathematics presents the most brilliant example of the
extension of the sphere of pure reason without the aid of experience.
Examples are always contagious; and they exert an especial influence on
the same faculty, which naturally flatters itself that it will have the
same good fortune in other case as fell to its lot in one fortunate
instance. Hence pure reason hopes to be able to extend its empire in
the transcendental sphere with equal success and security, especially
when it applies the same method which was attended with such brilliant
results in the science of mathematics. It is, therefore, of the highest
importance for us to know whether the method of arriving at
demonstrative certainty, which is termed mathematical, be identical
with that by which we endeavour to attain the same degree of certainty
in philosophy, and which is termed in that science dogmatical.
Philosophical cognition is the cognition of reason by means of
conceptions; mathematical cognition is cognition by means of the
construction of conceptions. The construction of a conception is the
presentation à priori of the intuition which corresponds to the
conception. For this purpose a non-empirical intuition is requisite,
which, as an intuition, is an individual object; while, as the
construction of a conception (a general representation), it must be
seen to be universally valid for all the possible intuitions which rank
under that conception. Thus I construct a triangle, by the presentation
of the object which corresponds to this conception, either by mere
imagination, in pure intuition, or upon paper, in empirical intuition,
in both cases completely à priori, without borrowing the type of that
figure from any experience. The individual figure drawn upon paper is
empirical; but it serves, notwithstanding, to indicate the conception,
even in its universality, because in this empirical intuition we keep
our eye merely on the act of the construction of the conception, and
pay no attention to the various modes of determining it, for example,
its size, the length of its sides, the size of its angles, these not in
the least affecting the essential character of the conception.
Philosophical cognition, accordingly, regards the particular only in
the general; mathematical the general in the particular, nay, in the
individual. This is done, however, entirely à priori and by means of
pure reason, so that, as this individual figure is determined under
certain universal conditions of construction, the object of the
conception, to which this individual figure corresponds as its schema,
must be cogitated as universally determined.
The essential difference of these two modes of cognition consists,
therefore, in this formal quality; it does not regard the difference of
the matter or objects of both. Those thinkers who aim at distinguishing
philosophy from mathematics by asserting that the former has to do with
quality merely, and the latter with quantity, have mistaken the effect
for the cause. The reason why mathematical cognition can relate only to
quantity is to be found in its form alone. For it is the conception of
quantities only that is capable of being constructed, that is,
presented à priori in intuition; while qualities cannot be given in any
other than an empirical intuition. Hence the cognition of qualities by
reason is possible only through conceptions. No one can find an
intuition which shall correspond to the conception of reality, except
in experience; it cannot be presented to the mind à priori and
antecedently to the empirical consciousness of a reality. We can form
an intuition, by means of the mere conception of it, of a cone, without
the aid of experience; but the colour of the cone we cannot know except
from experience. I cannot present an intuition of a cause, except in an
example which experience offers to me. Besides, philosophy, as well as
mathematics, treats of quantities; as, for example, of totality,
infinity, and so on. Mathematics, too, treats of the difference of
lines and surfaces—as spaces of different quality, of the continuity of
extension—as a quality thereof. But, although in such cases they have a
common object, the mode in which reason considers that object is very
different in philosophy from what it is in mathematics. The former
confines itself to the general conceptions; the latter can do nothing
with a mere conception, it hastens to intuition. In this intuition it
regards the conception in concreto, not empirically, but in an à priori
intuition, which it has constructed; and in which, all the results
which follow from the general conditions of the construction of the
conception are in all cases valid for the object of the constructed
conception.
Suppose that the conception of a triangle is given to a philosopher and
that he is required to discover, by the philosophical method, what
relation the sum of its angles bears to a right angle. He has nothing
before him but the conception of a figure enclosed within three right
lines, and, consequently, with the same number of angles. He may
analyse the conception of a right line, of an angle, or of the number
three as long as he pleases, but he will not discover any properties
not contained in these conceptions. But, if this question is proposed
to a geometrician, he at once begins by constructing a triangle. He
knows that two right angles are equal to the sum of all the contiguous
angles which proceed from one point in a straight line; and he goes on
to produce one side of his triangle, thus forming two adjacent angles
which are together equal to two right angles. He then divides the
exterior of these angles, by drawing a line parallel with the opposite
side of the triangle, and immediately perceives that he has thus got an
exterior adjacent angle which is equal to the interior. Proceeding in
this way, through a chain of inferences, and always on the ground of
intuition, he arrives at a clear and universally valid solution of the
question.
But mathematics does not confine itself to the construction of
quantities (quanta), as in the case of geometry; it occupies itself
with pure quantity also (quantitas), as in the case of algebra, where
complete abstraction is made of the properties of the object indicated
by the conception of quantity. In algebra, a certain method of notation
by signs is adopted, and these indicate the different possible
constructions of quantities, the extraction of roots, and so on. After
having thus denoted the general conception of quantities, according to
their different relations, the different operations by which quantity
or number is increased or diminished are presented in intuition in
accordance with general rules. Thus, when one quantity is to be divided
by another, the signs which denote both are placed in the form peculiar
to the operation of division; and thus algebra, by means of a
symbolical construction of quantity, just as geometry, with its
ostensive or geometrical construction (a construction of the objects
themselves), arrives at results which discursive cognition cannot hope
to reach by the aid of mere conceptions.
Now, what is the cause of this difference in the fortune of the
philosopher and the mathematician, the former of whom follows the path
of conceptions, while the latter pursues that of intuitions, which he
represents, à priori, in correspondence with his conceptions? The cause
is evident from what has been already demonstrated in the introduction
to this Critique. We do not, in the present case, want to discover
analytical propositions, which may be produced merely by analysing our
conceptions—for in this the philosopher would have the advantage over
his rival; we aim at the discovery of synthetical propositions—such
synthetical propositions, moreover, as can be cognized à priori. I must
not confine myself to that which I actually cogitate in my conception
of a triangle, for this is nothing more than the mere definition; I
must try to go beyond that, and to arrive at properties which are not
contained in, although they belong to, the conception. Now, this is
impossible, unless I determine the object present to my mind according
to the conditions, either of empirical, or of pure, intuition. In the
former case, I should have an empirical proposition (arrived at by
actual measurement of the angles of the triangle), which would possess
neither universality nor necessity; but that would be of no value. In
the latter, I proceed by geometrical construction, by means of which I
collect, in a pure intuition, just as I would in an empirical
intuition, all the various properties which belong to the schema of a
triangle in general, and consequently to its conception, and thus
construct synthetical propositions which possess the attribute of
universality.
It would be vain to philosophize upon the triangle, that is, to reflect
on it discursively; I should get no further than the definition with
which I had been obliged to set out. There are certainly transcendental
synthetical propositions which are framed by means of pure conceptions,
and which form the peculiar distinction of philosophy; but these do not
relate to any particular thing, but to a thing in general, and enounce
the conditions under which the perception of it may become a part of
possible experience. But the science of mathematics has nothing to do
with such questions, nor with the question of existence in any fashion;
it is concerned merely with the properties of objects in themselves,
only in so far as these are connected with the conception of the
objects.
In the above example, we merely attempted to show the great difference
which exists between the discursive employment of reason in the sphere
of conceptions, and its intuitive exercise by means of the construction
of conceptions. The question naturally arises: What is the cause which
necessitates this twofold exercise of reason, and how are we to
discover whether it is the philosophical or the mathematical method
which reason is pursuing in an argument?
All our knowledge relates, finally, to possible intuitions, for it is
these alone that present objects to the mind. An à priori or
non-empirical conception contains either a pure intuition—and in this
case it can be constructed; or it contains nothing but the synthesis of
possible intuitions, which are not given à priori. In this latter case,
it may help us to form synthetical à priori judgements, but only in the
discursive method, by conceptions, not in the intuitive, by means of
the construction of conceptions.
The only à priori intuition is that of the pure form of phenomena—space
and time. A conception of space and time as quanta may be presented à
priori in intuition, that is, constructed, either alone with their
quality (figure), or as pure quantity (the mere synthesis of the
homogeneous), by means of number. But the matter of phenomena, by which
things are given in space and time, can be presented only in
perception, à posteriori. The only conception which represents à priori
this empirical content of phenomena is the conception of a thing in
general; and the à priori synthetical cognition of this conception can
give us nothing more than the rule for the synthesis of that which may
be contained in the corresponding à posteriori perception; it is
utterly inadequate to present an à priori intuition of the real object,
which must necessarily be empirical.
Synthetical propositions, which relate to things in general, an à
priori intuition of which is impossible, are transcendental. For this
reason transcendental propositions cannot be framed by means of the
construction of conceptions; they are à priori, and based entirely on
conceptions themselves. They contain merely the rule, by which we are
to seek in the world of perception or experience the synthetical unity
of that which cannot be intuited à priori. But they are incompetent to
present any of the conceptions which appear in them in an à priori
intuition; these can be given only à posteriori, in experience, which,
however, is itself possible only through these synthetical principles.
If we are to form a synthetical judgement regarding a conception,
we must go beyond it, to the intuition in which it is given. If we
keep to what is contained in the conception, the judgement is merely
analytical—it is merely an explanation of what we have cogitated in
the conception. But I can pass from the conception to the pure or
empirical intuition which corresponds to it. I can proceed to examine
my conception in concreto, and to cognize, either à priori or à
posteriori, what I find in the object of the conception. The former—à
priori cognition—is rational-mathematical cognition by means of the
construction of the conception; the latter—à posteriori cognition—is
purely empirical cognition, which does not possess the attributes
of necessity and universality. Thus I may analyse the conception I
have of gold; but I gain no new information from this analysis, I
merely enumerate the different properties which I had connected with
the notion indicated by the word. My knowledge has gained in logical
clearness and arrangement, but no addition has been made to it. But
if I take the matter which is indicated by this name, and submit
it to the examination of my senses, I am enabled to form several
synthetical—although still empirical—propositions. The mathematical
conception of a triangle I should construct, that is, present à priori
in intuition, and in this way attain to rational-synthetical cognition.
But when the transcendental conception of reality, or substance, or
power is presented to my mind, I find that it does not relate to or
indicate either an empirical or pure intuition, but that it indicates
merely the synthesis of empirical intuitions, which cannot of course
be given à priori. The synthesis in such a conception cannot proceed à
priori—without the aid of experience—to the intuition which corresponds
to the conception; and, for this reason, none of these conceptions can
produce a determinative synthetical proposition, they can never present
more than a principle of the synthesis[75] of possible empirical
intuitions. A transcendental proposition is, therefore, a synthetical
cognition of reason by means of pure conceptions and the discursive
method, and it renders possible all synthetical unity in empirical
cognition, though it cannot present us with any intuition à priori.
[75] In the case of the conception of cause, I do really go beyond the
empirical conception of an event—but not to the intuition which
presents this conception in concreto, but only to the time-conditions,
which may be found in experience to correspond to the conception. My
procedure is, therefore, strictly according to conceptions; I cannot
in a case of this kind employ the construction of conceptions, because
the conception is merely a rule for the synthesis of perceptions,
which are not pure intuitions, and which, therefore, cannot be given à
priori.
There is thus a twofold exercise of reason. Both modes have the
properties of universality and an à priori origin in common, but are,
in their procedure, of widely different character. The reason of this
is that in the world of phenomena, in which alone objects are presented
to our minds, there are two main elements—the form of intuition (space
and time), which can be cognized and determined completely à priori,
and the matter or content—that which is presented in space and time,
and which, consequently, contains a something—an existence
corresponding to our powers of sensation. As regards the latter, which
can never be given in a determinate mode except by experience, there
are no à priori notions which relate to it, except the undetermined
conceptions of the synthesis of possible sensations, in so far as these
belong (in a possible experience) to the unity of consciousness. As
regards the former, we can determine our conceptions à priori in
intuition, inasmuch as we are ourselves the creators of the objects of
the conceptions in space and time—these objects being regarded simply
as quanta. In the one case, reason proceeds according to conceptions
and can do nothing more than subject phenomena to these—which can only
be determined empirically, that is, à posteriori—in conformity,
however, with those conceptions as the rules of all empirical
synthesis. In the other case, reason proceeds by the construction of
conceptions; and, as these conceptions relate to an à priori intuition,
they may be given and determined in pure intuition à priori, and
without the aid of empirical data. The examination and consideration of
everything that exists in space or time—whether it is a quantum or not,
in how far the particular something (which fills space or time) is a
primary substratum, or a mere determination of some other existence,
whether it relates to anything else—either as cause or effect, whether
its existence is isolated or in reciprocal connection with and
dependence upon others, the possibility of this existence, its reality
and necessity or opposites—all these form part of the cognition of
reason on the ground of conceptions, and this cognition is termed
philosophical. But to determine à priori an intuition in space (its
figure), to divide time into periods, or merely to cognize the quantity
of an intuition in space and time, and to determine it by number—all
this is an operation of reason by means of the construction of
conceptions, and is called mathematical.
The success which attends the efforts of reason in the sphere of
mathematics naturally fosters the expectation that the same good
fortune will be its lot, if it applies the mathematical method in other
regions of mental endeavour besides that of quantities. Its success is
thus great, because it can support all its conceptions by à priori
intuitions and, in this way, make itself a master, as it were, over
nature; while pure philosophy, with its à priori discursive
conceptions, bungles about in the world of nature, and cannot accredit
or show any à priori evidence of the reality of these conceptions.
Masters in the science of mathematics are confident of the success of
this method; indeed, it is a common persuasion that it is capable of
being applied to any subject of human thought. They have hardly ever
reflected or philosophized on their favourite science—a task of great
difficulty; and the specific difference between the two modes of
employing the faculty of reason has never entered their thoughts. Rules
current in the field of common experience, and which common sense
stamps everywhere with its approval, are regarded by them as axiomatic.
From what source the conceptions of space and time, with which (as the
only primitive quanta) they have to deal, enter their minds, is a
question which they do not trouble themselves to answer; and they think
it just as unnecessary to examine into the origin of the pure
conceptions of the understanding and the extent of their validity. All
they have to do with them is to employ them. In all this they are
perfectly right, if they do not overstep the limits of the sphere of
nature. But they pass, unconsciously, from the world of sense to the
insecure ground of pure transcendental conceptions (instabilis tellus,
innabilis unda), where they can neither stand nor swim, and where the
tracks of their footsteps are obliterated by time; while the march of
mathematics is pursued on a broad and magnificent highway, which the
latest posterity shall frequent without fear of danger or impediment.
As we have taken upon us the task of determining, clearly and
certainly, the limits of pure reason in the sphere of
transcendentalism, and as the efforts of reason in this direction are
persisted in, even after the plainest and most expressive warnings,
hope still beckoning us past the limits of experience into the
splendours of the intellectual world—it becomes necessary to cut away
the last anchor of this fallacious and fantastic hope. We shall,
accordingly, show that the mathematical method is unattended in the
sphere of philosophy by the least advantage—except, perhaps, that it
more plainly exhibits its own inadequacy—that geometry and philosophy
are two quite different things, although they go hand in hand in the
field of natural science, and, consequently, that the procedure of the
one can never be imitated by the other.
The evidence of mathematics rests upon definitions, axioms, and
demonstrations. I shall be satisfied with showing that none of these
forms can be employed or imitated in philosophy in the sense in which
they are understood by mathematicians; and that the geometrician, if he
employs his method in philosophy, will succeed only in building
card-castles, while the employment of the philosophical method in
mathematics can result in nothing but mere verbiage. The essential
business of philosophy, indeed, is to mark out the limits of the
science; and even the mathematician, unless his talent is naturally
circumscribed and limited to this particular department of knowledge,
cannot turn a deaf ear to the warnings of philosophy, or set himself
above its direction.
I. Of Definitions. A definition is, as the term itself indicates, the
representation, upon primary grounds, of the complete conception of a
thing within its own limits.[76] Accordingly, an empirical conception
cannot be defined, it can only be explained. For, as there are in such
a conception only a certain number of marks or signs, which denote a
certain class of sensuous objects, we can never be sure that we do not
cogitate under the word which indicates the same object, at one time a
greater, at another a smaller number of signs. Thus, one person may
cogitate in his conception of gold, in addition to its properties of
weight, colour, malleability, that of resisting rust, while another
person may be ignorant of this quality. We employ certain signs only so
long as we require them for the sake of distinction; new observations
abstract some and add new ones, so that an empirical conception never
remains within permanent limits. It is, in fact, useless to define a
conception of this kind. If, for example, we are speaking of water and
its properties, we do not stop at what we actually think by the word
water, but proceed to observation and experiment; and the word, with
the few signs attached to it, is more properly a designation than a
conception of the thing. A definition in this case would evidently be
nothing more than a determination of the word. In the second place, no
à priori conception, such as those of substance, cause, right, fitness,
and so on, can be defined. For I can never be sure, that the clear
representation of a given conception (which is given in a confused
state) has been fully developed, until I know that the representation
is adequate with its object. But, inasmuch as the conception, as it is
presented to the mind, may contain a number of obscure representations,
which we do not observe in our analysis, although we employ them in our
application of the conception, I can never be sure that my analysis is
complete, while examples may make this probable, although they can
never demonstrate the fact. Instead of the word definition, I should
rather employ the term exposition—a more modest expression, which the
critic may accept without surrendering his doubts as to the
completeness of the analysis of any such conception. As, therefore,
neither empirical nor à priori conceptions are capable of definition,
we have to see whether the only other kind of conceptions—arbitrary
conceptions—can be subjected to this mental operation. Such a
conception can always be defined; for I must know thoroughly what I
wished to cogitate in it, as it was I who created it, and it was not
given to my mind either by the nature of my understanding or by
experience. At the same time, I cannot say that, by such a definition,
I have defined a real object. If the conception is based upon empirical
conditions, if, for example, I have a conception of a clock for a ship,
this arbitrary conception does not assure me of the existence or even
of the possibility of the object. My definition of such a conception
would with more propriety be termed a declaration of a project than a
definition of an object. There are no other conceptions which can bear
definition, except those which contain an arbitrary synthesis, which
can be constructed à priori. Consequently, the science of mathematics
alone possesses definitions. For the object here thought is presented à
priori in intuition; and thus it can never contain more or less than
the conception, because the conception of the object has been given by
the definition—and primarily, that is, without deriving the definition
from any other source. Philosophical definitions are, therefore, merely
expositions of given conceptions, while mathematical definitions are
constructions of conceptions originally formed by the mind itself; the
former are produced by analysis, the completeness of which is never
demonstratively certain, the latter by a synthesis. In a mathematical
definition the conception is formed, in a philosophical definition it
is only explained. From this it follows:
[76] The definition must describe the conception completely that is,
omit none of the marks or signs of which it composed; within its own
limits, that is, it must be precise, and enumerate no more signs than
belong to the conception; and on primary grounds, that is to say, the
limitations of the bounds of the conception must not be deduced from
other conceptions, as in this case a proof would be necessary, and the
so-called definition would be incapable of taking its place at the
head of all the judgements we have to form regarding an object.
(a) That we must not imitate, in philosophy, the mathematical usage of
commencing with definitions—except by way of hypothesis or experiment.
For, as all so-called philosophical definitions are merely analyses of
given conceptions, these conceptions, although only in a confused form,
must precede the analysis; and the incomplete exposition must precede
the complete, so that we may be able to draw certain inferences from
the characteristics which an incomplete analysis has enabled us to
discover, before we attain to the complete exposition or definition of
the conception. In one word, a full and clear definition ought, in
philosophy, rather to form the conclusion than the commencement of our
labours.[77] In mathematics, on the contrary, we cannot have a
conception prior to the definition; it is the definition which gives us
the conception, and it must for this reason form the commencement of
every chain of mathematical reasoning.
[77] Philosophy abounds in faulty definitions, especially such as
contain some of the elements requisite to form a complete definition.
If a conception could not be employed in reasoning before it had been
defined, it would fare ill with all philosophical thought. But, as
incompletely defined conceptions may always be employed without
detriment to truth, so far as our analysis of the elements contained
in them proceeds, imperfect definitions, that is, propositions which
are properly not definitions, but merely approximations thereto, may
be used with great advantage. In mathematics, definition belongs ad
esse, in philosophy ad melius esse. It is a difficult task to
construct a proper definition. Jurists are still without a complete
definition of the idea of right.
(b) Mathematical definitions cannot be erroneous. For the conception is
given only in and through the definition, and thus it contains only
what has been cogitated in the definition. But although a definition
cannot be incorrect, as regards its content, an error may sometimes,
although seldom, creep into the form. This error consists in a want of
precision. Thus the common definition of a circle—that it is a curved
line, every point in which is equally distant from another point called
the centre—is faulty, from the fact that the determination indicated by
the word curved is superfluous. For there ought to be a particular
theorem, which may be easily proved from the definition, to the effect
that every line, which has all its points at equal distances from
another point, must be a curved line—that is, that not even the
smallest part of it can be straight. Analytical definitions, on the
other hand, may be erroneous in many respects, either by the
introduction of signs which do not actually exist in the conception, or
by wanting in that completeness which forms the essential of a
definition. In the latter case, the definition is necessarily
defective, because we can never be fully certain of the completeness of
our analysis. For these reasons, the method of definition employed in
mathematics cannot be imitated in philosophy.
2. Of Axioms. These, in so far as they are immediately certain, are à
priori synthetical principles. Now, one conception cannot be connected
synthetically and yet immediately with another; because, if we wish to
proceed out of and beyond a conception, a third mediating cognition is
necessary. And, as philosophy is a cognition of reason by the aid of
conceptions alone, there is to be found in it no principle which
deserves to be called an axiom. Mathematics, on the other hand, may
possess axioms, because it can always connect the predicates of an
object à priori, and without any mediating term, by means of the
construction of conceptions in intuition. Such is the case with the
proposition: Three points can always lie in a plane. On the other hand,
no synthetical principle which is based upon conceptions, can ever be
immediately certain (for example, the proposition: Everything that
happens has a cause), because I require a mediating term to connect the
two conceptions of event and cause—namely, the condition of
time-determination in an experience, and I cannot cognize any such
principle immediately and from conceptions alone. Discursive principles
are, accordingly, very different from intuitive principles or axioms.
The former always require deduction, which in the case of the latter
may be altogether dispensed with. Axioms are, for this reason, always
self-evident, while philosophical principles, whatever may be the
degree of certainty they possess, cannot lay any claim to such a
distinction. No synthetical proposition of pure transcendental reason
can be so evident, as is often rashly enough declared, as the
statement, twice two are four. It is true that in the Analytic I
introduced into the list of principles of the pure understanding,
certain axioms of intuition; but the principle there discussed was not
itself an axiom, but served merely to present the principle of the
possibility of axioms in general, while it was really nothing more than
a principle based upon conceptions. For it is one part of the duty of
transcendental philosophy to establish the possibility of mathematics
itself. Philosophy possesses, then, no axioms, and has no right to
impose its à priori principles upon thought, until it has established
their authority and validity by a thoroughgoing deduction.
3. Of Demonstrations. Only an apodeictic proof, based upon intuition,
can be termed a demonstration. Experience teaches us what is, but it
cannot convince us that it might not have been otherwise. Hence a proof
upon empirical grounds cannot be apodeictic. À priori conceptions, in
discursive cognition, can never produce intuitive certainty or
evidence, however certain the judgement they present may be.
Mathematics alone, therefore, contains demonstrations, because it does
not deduce its cognition from conceptions, but from the construction of
conceptions, that is, from intuition, which can be given à priori in
accordance with conceptions. The method of algebra, in equations, from
which the correct answer is deduced by reduction, is a kind of
construction—not geometrical, but by symbols—in which all conceptions,
especially those of the relations of quantities, are represented in
intuition by signs; and thus the conclusions in that science are
secured from errors by the fact that every proof is submitted to ocular
evidence. Philosophical cognition does not possess this advantage, it
being required to consider the general always in abstracto (by means of
conceptions), while mathematics can always consider it in concreto (in
an individual intuition), and at the same time by means of à priori
representation, whereby all errors are rendered manifest to the senses.
The former—discursive proofs—ought to be termed acroamatic proofs,
rather than demonstrations, as only words are employed in them, while
demonstrations proper, as the term itself indicates, always require a
reference to the intuition of the object.
It follows from all these considerations that it is not consonant with
the nature of philosophy, especially in the sphere of pure reason, to
employ the dogmatical method, and to adorn itself with the titles and
insignia of mathematical science. It does not belong to that order, and
can only hope for a fraternal union with that science. Its attempts at
mathematical evidence are vain pretensions, which can only keep it back
from its true aim, which is to detect the illusory procedure of reason
when transgressing its proper limits, and by fully explaining and
analysing our conceptions, to conduct us from the dim regions of
speculation to the clear region of modest self-knowledge. Reason must
not, therefore, in its transcendental endeavours, look forward with
such confidence, as if the path it is pursuing led straight to its aim,
nor reckon with such security upon its premisses, as to consider it
unnecessary to take a step back, or to keep a strict watch for errors,
which, overlooked in the principles, may be detected in the arguments
themselves—in which case it may be requisite either to determine these
principles with greater strictness, or to change them entirely.
I divide all apodeictic propositions, whether demonstrable or
immediately certain, into dogmata and mathemata. A direct synthetical
proposition, based on conceptions, is a dogma; a proposition of the
same kind, based on the construction of conceptions, is a mathema.
Analytical judgements do not teach us any more about an object than
what was contained in the conception we had of it; because they do not
extend our cognition beyond our conception of an object, they merely
elucidate the conception. They cannot therefore be with propriety
termed dogmas. Of the two kinds of à priori synthetical propositions
above mentioned, only those which are employed in philosophy can,
according to the general mode of speech, bear this name; those of
arithmetic or geometry would not be rightly so denominated. Thus the
customary mode of speaking confirms the explanation given above, and
the conclusion arrived at, that only those judgements which are based
upon conceptions, not on the construction of conceptions, can be termed
dogmatical.
Thus, pure reason, in the sphere of speculation, does not contain a
single direct synthetical judgement based upon conceptions. By means of
ideas, it is, as we have shown, incapable of producing synthetical
judgements, which are objectively valid; by means of the conceptions of
the understanding, it establishes certain indubitable principles, not,
however, directly on the basis of conceptions, but only indirectly by
means of the relation of these conceptions to something of a purely
contingent nature, namely, possible experience. When experience is
presupposed, these principles are apodeictically certain, but in
themselves, and directly, they cannot even be cognized à priori. Thus
the given conceptions of cause and event will not be sufficient for the
demonstration of the proposition: Every event has a cause. For this
reason, it is not a dogma; although from another point of view, that of
experience, it is capable of being proved to demonstration. The proper
term for such a proposition is principle, and not theorem (although it
does require to be proved), because it possesses the remarkable
peculiarity of being the condition of the possibility of its own ground
of proof, that is, experience, and of forming a necessary
presupposition in all empirical observation.
If then, in the speculative sphere of pure reason, no dogmata are to be
found; all dogmatical methods, whether borrowed from mathematics, or
invented by philosophical thinkers, are alike inappropriate and
inefficient. They only serve to conceal errors and fallacies, and to
deceive philosophy, whose duty it is to see that reason pursues a safe
and straight path. A philosophical method may, however, be
systematical. For our reason is, subjectively considered, itself a
system, and, in the sphere of mere conceptions, a system of
investigation according to principles of unity, the material being
supplied by experience alone. But this is not the proper place for
discussing the peculiar method of transcendental philosophy, as our
present task is simply to examine whether our faculties are capable of
erecting an edifice on the basis of pure reason, and how far they may
proceed with the materials at their command.
Section II. The Discipline of Pure Reason in Polemics
Reason must be subject, in all its operations, to criticism, which must
always be permitted to exercise its functions without restraint;
otherwise its interests are imperilled and its influence obnoxious to
suspicion. There is nothing, however useful, however sacred it may be,
that can claim exemption from the searching examination of this supreme
tribunal, which has no respect of persons. The very existence of reason
depends upon this freedom; for the voice of reason is not that of a
dictatorial and despotic power, it is rather like the vote of the
citizens of a free state, every member of which must have the privilege
of giving free expression to his doubts, and possess even the right of
veto.
But while reason can never decline to submit itself to the tribunal of
criticism, it has not always cause to dread the judgement of this
court. Pure reason, however, when engaged in the sphere of dogmatism,
is not so thoroughly conscious of a strict observance of its highest
laws, as to appear before a higher judicial reason with perfect
confidence. On the contrary, it must renounce its magnificent
dogmatical pretensions in philosophy.
Very different is the case when it has to defend itself, not before a
judge, but against an equal. If dogmatical assertions are advanced on
the negative side, in opposition to those made by reason on the
positive side, its justification kat authrhopon is complete, although
the proof of its propositions is kat aletheian unsatisfactory.
By the polemic of pure reason I mean the defence of its propositions
made by reason, in opposition to the dogmatical counter-propositions
advanced by other parties. The question here is not whether its own
statements may not also be false; it merely regards the fact that
reason proves that the opposite cannot be established with
demonstrative certainty, nor even asserted with a higher degree of
probability. Reason does not hold her possessions upon sufferance; for,
although she cannot show a perfectly satisfactory title to them, no one
can prove that she is not the rightful possessor.
It is a melancholy reflection that reason, in its highest exercise,
falls into an antithetic; and that the supreme tribunal for the
settlement of differences should not be at union with itself. It is
true that we had to discuss the question of an apparent antithetic, but
we found that it was based upon a misconception. In conformity with the
common prejudice, phenomena were regarded as things in themselves, and
thus an absolute completeness in their synthesis was required in the
one mode or in the other (it was shown to be impossible in both); a
demand entirely out of place in regard to phenomena. There was, then,
no real self-contradiction of reason in the propositions: The series of
phenomena given in themselves has an absolutely first beginning; and:
This series is absolutely and in itself without beginning. The two
propositions are perfectly consistent with each other, because
phenomena as phenomena are in themselves nothing, and consequently the
hypothesis that they are things in themselves must lead to
self-contradictory inferences.
But there are cases in which a similar misunderstanding cannot be
provided against, and the dispute must remain unsettled. Take, for
example, the theistic proposition: There is a Supreme Being; and on the
other hand, the atheistic counter-statement: There exists no Supreme
Being; or, in psychology: Everything that thinks possesses the
attribute of absolute and permanent unity, which is utterly different
from the transitory unity of material phenomena; and the
counter-proposition: The soul is not an immaterial unity, and its
nature is transitory, like that of phenomena. The objects of these
questions contain no heterogeneous or contradictory elements, for they
relate to things in themselves, and not to phenomena. There would
arise, indeed, a real contradiction, if reason came forward with a
statement on the negative side of these questions alone. As regards the
criticism to which the grounds of proof on the affirmative side must be
subjected, it may be freely admitted, without necessitating the
surrender of the affirmative propositions, which have, at least, the
interest of reason in their favour—an advantage which the opposite
party cannot lay claim to.
I cannot agree with the opinion of several admirable thinkers—Sulzer
among the rest—that, in spite of the weakness of the arguments hitherto
in use, we may hope, one day, to see sufficient demonstrations of the
two cardinal propositions of pure reason—the existence of a Supreme
Being, and the immortality of the soul. I am certain, on the contrary,
that this will never be the case. For on what ground can reason base
such synthetical propositions, which do not relate to the objects of
experience and their internal possibility? But it is also
demonstratively certain that no one will ever be able to maintain the
contrary with the least show of probability. For, as he can attempt
such a proof solely upon the basis of pure reason, he is bound to prove
that a Supreme Being, and a thinking subject in the character of a pure
intelligence, are impossible. But where will he find the knowledge
which can enable him to enounce synthetical judgements in regard to
things which transcend the region of experience? We may, therefore,
rest assured that the opposite never will be demonstrated. We need not,
then, have recourse to scholastic arguments; we may always admit the
truth of those propositions which are consistent with the speculative
interests of reason in the sphere of experience, and form, moreover,
the only means of uniting the speculative with the practical interest.
Our opponent, who must not be considered here as a critic solely, we
can be ready to meet with a non liquet which cannot fail to disconcert
him; while we cannot deny his right to a similar retort, as we have on
our side the advantage of the support of the subjective maxim of
reason, and can therefore look upon all his sophistical arguments with
calm indifference.
From this point of view, there is properly no antithetic of pure
reason. For the only arena for such a struggle would be upon the field
of pure theology and psychology; but on this ground there can appear no
combatant whom we need to fear. Ridicule and boasting can be his only
weapons; and these may be laughed at, as mere child’s play. This
consideration restores to Reason her courage; for what source of
confidence could be found, if she, whose vocation it is to destroy
error, were at variance with herself and without any reasonable hope of
ever reaching a state of permanent repose?
Everything in nature is good for some purpose. Even poisons are
serviceable; they destroy the evil effects of other poisons generated
in our system, and must always find a place in every complete
pharmacopoeia. The objections raised against the fallacies and
sophistries of speculative reason, are objections given by the nature
of this reason itself, and must therefore have a destination and
purpose which can only be for the good of humanity. For what purpose
has Providence raised many objects, in which we have the deepest
interest, so far above us, that we vainly try to cognize them with
certainty, and our powers of mental vision are rather excited than
satisfied by the glimpses we may chance to seize? It is very doubtful
whether it is for our benefit to advance bold affirmations regarding
subjects involved in such obscurity; perhaps it would even be
detrimental to our best interests. But it is undoubtedly always
beneficial to leave the investigating, as well as the critical reason,
in perfect freedom, and permit it to take charge of its own interests,
which are advanced as much by its limitation, as by its extension of
its views, and which always suffer by the interference of foreign
powers forcing it, against its natural tendencies, to bend to certain
preconceived designs.
Allow your opponent to say what he thinks reasonable, and combat him
only with the weapons of reason. Have no anxiety for the practical
interests of humanity—these are never imperilled in a purely
speculative dispute. Such a dispute serves merely to disclose the
antinomy of reason, which, as it has its source in the nature of
reason, ought to be thoroughly investigated. Reason is benefited by the
examination of a subject on both sides, and its judgements are
corrected by being limited. It is not the matter that may give occasion
to dispute, but the manner. For it is perfectly permissible to employ,
in the presence of reason, the language of a firmly rooted faith, even
after we have been obliged to renounce all pretensions to knowledge.
If we were to ask the dispassionate David Hume—a philosopher endowed,
in a degree that few are, with a well-balanced judgement: What motive
induced you to spend so much labour and thought in undermining the
consoling and beneficial persuasion that reason is capable of assuring
us of the existence, and presenting us with a determinate conception of
a Supreme Being?—his answer would be: Nothing but the desire of
teaching reason to know its own powers better, and, at the same time, a
dislike of the procedure by which that faculty was compelled to support
foregone conclusions, and prevented from confessing the internal
weaknesses which it cannot but feel when it enters upon a rigid
self-examination. If, on the other hand, we were to ask Priestley—a
philosopher who had no taste for transcendental speculation, but was
entirely devoted to the principles of empiricism—what his motives were
for overturning those two main pillars of religion—the doctrines of the
freedom of the will and the immortality of the soul (in his view the
hope of a future life is but the expectation of the miracle of
resurrection)—this philosopher, himself a zealous and pious teacher of
religion, could give no other answer than this: I acted in the interest
of reason, which always suffers, when certain objects are explained and
judged by a reference to other supposed laws than those of material
nature—the only laws which we know in a determinate manner. It would be
unfair to decry the latter philosopher, who endeavoured to harmonize
his paradoxical opinions with the interests of religion, and to
undervalue an honest and reflecting man, because he finds himself at a
loss the moment he has left the field of natural science. The same
grace must be accorded to Hume, a man not less well-disposed, and quite
as blameless in his moral character, and who pushed his abstract
speculations to an extreme length, because, as he rightly believed, the
object of them lies entirely beyond the bounds of natural science, and
within the sphere of pure ideas.
What is to be done to provide against the danger which seems in the
present case to menace the best interests of humanity? The course to be
pursued in reference to this subject is a perfectly plain and natural
one. Let each thinker pursue his own path; if he shows talent, if he
gives evidence of profound thought, in one word, if he shows that he
possesses the power of reasoning—reason is always the gainer. If you
have recourse to other means, if you attempt to coerce reason, if you
raise the cry of treason to humanity, if you excite the feelings of the
crowd, which can neither understand nor sympathize with such subtle
speculations—you will only make yourselves ridiculous. For the question
does not concern the advantage or disadvantage which we are expected to
reap from such inquiries; the question is merely how far reason can
advance in the field of speculation, apart from all kinds of interest,
and whether we may depend upon the exertions of speculative reason, or
must renounce all reliance on it. Instead of joining the combatants, it
is your part to be a tranquil spectator of the struggle—a laborious
struggle for the parties engaged, but attended, in its progress as well
as in its result, with the most advantageous consequences for the
interests of thought and knowledge. It is absurd to expect to be
enlightened by Reason, and at the same time to prescribe to her what
side of the question she must adopt. Moreover, reason is sufficiently
held in check by its own power, the limits imposed on it by its own
nature are sufficient; it is unnecessary for you to place over it
additional guards, as if its power were dangerous to the constitution
of the intellectual state. In the dialectic of reason there is no
victory gained which need in the least disturb your tranquility.
The strife of dialectic is a necessity of reason, and we cannot but
wish that it had been conducted long ere this with that perfect freedom
which ought to be its essential condition. In this case, we should have
had at an earlier period a matured and profound criticism, which must
have put an end to all dialectical disputes, by exposing the illusions
and prejudices in which they originated.
There is in human nature an unworthy propensity—a propensity which,
like everything that springs from nature, must in its final purpose be
conducive to the good of humanity—to conceal our real sentiments, and
to give expression only to certain received opinions, which are
regarded as at once safe and promotive of the common good. It is true,
this tendency, not only to conceal our real sentiments, but to profess
those which may gain us favour in the eyes of society, has not only
civilized, but, in a certain measure, moralized us; as no one can break
through the outward covering of respectability, honour, and morality,
and thus the seemingly-good examples which we see around us form an
excellent school for moral improvement, so long as our belief in their
genuineness remains unshaken. But this disposition to represent
ourselves as better than we are, and to utter opinions which are not
our own, can be nothing more than a kind of provisionary arrangement of
nature to lead us from the rudeness of an uncivilized state, and to
teach us how to assume at least the appearance and manner of the good
we see. But when true principles have been developed, and have obtained
a sure foundation in our habit of thought, this conventionalism must be
attacked with earnest vigour, otherwise it corrupts the heart, and
checks the growth of good dispositions with the mischievous weed of
fair appearances.
I am sorry to remark the same tendency to misrepresentation and
hypocrisy in the sphere of speculative discussion, where there is less
temptation to restrain the free expression of thought. For what can be
more prejudicial to the interests of intelligence than to falsify our
real sentiments, to conceal the doubts which we feel in regard to our
statements, or to maintain the validity of grounds of proof which we
well know to be insufficient? So long as mere personal vanity is the
source of these unworthy artifices—and this is generally the case in
speculative discussions, which are mostly destitute of practical
interest, and are incapable of complete demonstration—the vanity of the
opposite party exaggerates as much on the other side; and thus the
result is the same, although it is not brought about so soon as if the
dispute had been conducted in a sincere and upright spirit. But where
the mass entertains the notion that the aim of certain subtle
speculators is nothing less than to shake the very foundations of
public welfare and morality—it seems not only prudent, but even praise
worthy, to maintain the good cause by illusory arguments, rather than
to give to our supposed opponents the advantage of lowering our
declarations to the moderate tone of a merely practical conviction, and
of compelling us to confess our inability to attain to apodeictic
certainty in speculative subjects. But we ought to reflect that there
is nothing, in the world more fatal to the maintenance of a good cause
than deceit, misrepresentation, and falsehood. That the strictest laws
of honesty should be observed in the discussion of a purely speculative
subject is the least requirement that can be made. If we could reckon
with security even upon so little, the conflict of speculative reason
regarding the important questions of God, immortality, and freedom,
would have been either decided long ago, or would very soon be brought
to a conclusion. But, in general, the uprightness of the defence stands
in an inverse ratio to the goodness of the cause; and perhaps more
honesty and fairness are shown by those who deny than by those who
uphold these doctrines.
I shall persuade myself, then, that I have readers who do not wish to
see a righteous cause defended by unfair arguments. Such will now
recognize the fact that, according to the principles of this Critique,
if we consider not what is, but what ought to be the case, there can be
really no polemic of pure reason. For how can two persons dispute about
a thing, the reality of which neither can present in actual or even in
possible experience? Each adopts the plan of meditating on his idea for
the purpose of drawing from the idea, if he can, what is more than the
idea, that is, the reality of the object which it indicates. How shall
they settle the dispute, since neither is able to make his assertions
directly comprehensible and certain, but must restrict himself to
attacking and confuting those of his opponent? All statements enounced
by pure reason transcend the conditions of possible experience, beyond
the sphere of which we can discover no criterion of truth, while they
are at the same time framed in accordance with the laws of the
understanding, which are applicable only to experience; and thus it is
the fate of all such speculative discussions that while the one party
attacks the weaker side of his opponent, he infallibly lays open his
own weaknesses.
The critique of pure reason may be regarded as the highest tribunal for
all speculative disputes; for it is not involved in these disputes,
which have an immediate relation to certain objects and not to the laws
of the mind, but is instituted for the purpose of determining the
rights and limits of reason.
Without the control of criticism, reason is, as it were, in a state of
nature, and can only establish its claims and assertions by war.
Criticism, on the contrary, deciding all questions according to the
fundamental laws of its own institution, secures to us the peace of law
and order, and enables us to discuss all differences in the more
tranquil manner of a legal process. In the former case, disputes are
ended by victory, which both sides may claim and which is followed by a
hollow armistice; in the latter, by a sentence, which, as it strikes at
the root of all speculative differences, ensures to all concerned a
lasting peace. The endless disputes of a dogmatizing reason compel us
to look for some mode of arriving at a settled decision by a critical
investigation of reason itself; just as Hobbes maintains that the state
of nature is a state of injustice and violence, and that we must leave
it and submit ourselves to the constraint of law, which indeed limits
individual freedom, but only that it may consist with the freedom of
others and with the common good of all.
This freedom will, among other things, permit of our openly stating the
difficulties and doubts which we are ourselves unable to solve, without
being decried on that account as turbulent and dangerous citizens. This
privilege forms part of the native rights of human reason, which
recognizes no other judge than the universal reason of humanity; and as
this reason is the source of all progress and improvement, such a
privilege is to be held sacred and inviolable. It is unwise, moreover,
to denounce as dangerous any bold assertions against, or rash attacks
upon, an opinion which is held by the largest and most moral class of
the community; for that would be giving them an importance which they
do not deserve. When I hear that the freedom of the will, the hope of a
future life, and the existence of God have been overthrown by the
arguments of some able writer, I feel a strong desire to read his book;
for I expect that he will add to my knowledge and impart greater
clearness and distinctness to my views by the argumentative power shown
in his writings. But I am perfectly certain, even before I have opened
the book, that he has not succeeded in a single point, not because I
believe I am in possession of irrefutable demonstrations of these
important propositions, but because this transcendental critique, which
has disclosed to me the power and the limits of pure reason, has fully
convinced me that, as it is insufficient to establish the affirmative,
it is as powerless, and even more so, to assure us of the truth of the
negative answer to these questions. From what source does this
free-thinker derive his knowledge that there is, for example, no
Supreme Being? This proposition lies out of the field of possible
experience, and, therefore, beyond the limits of human cognition. But I
would not read at, all the answer which the dogmatical maintainer of
the good cause makes to his opponent, because I know well beforehand,
that he will merely attack the fallacious grounds of his adversary,
without being able to establish his own assertions. Besides, a new
illusory argument, in the construction of which talent and acuteness
are shown, is suggestive of new ideas and new trains of reasoning, and
in this respect the old and everyday sophistries are quite useless.
Again, the dogmatical opponent of religion gives employment to
criticism, and enables us to test and correct its principles, while
there is no occasion for anxiety in regard to the influence and results
of his reasoning.
But, it will be said, must we not warn the youth entrusted to
academical care against such writings, must we not preserve them from
the knowledge of these dangerous assertions, until their judgement is
ripened, or rather until the doctrines which we wish to inculcate are
so firmly rooted in their minds as to withstand all attempts at
instilling the contrary dogmas, from whatever quarter they may come?
If we are to confine ourselves to the dogmatical procedure in the
sphere of pure reason, and find ourselves unable to settle such
disputes otherwise than by becoming a party in them, and setting
counter-assertions against the statements advanced by our opponents,
there is certainly no plan more advisable for the moment, but, at the
same time, none more absurd and inefficient for the future, than this
retaining of the youthful mind under guardianship for a time, and thus
preserving it—for so long at least—from seduction into error. But when,
at a later period, either curiosity, or the prevalent fashion of
thought places such writings in their hands, will the so-called
convictions of their youth stand firm? The young thinker, who has in
his armoury none but dogmatical weapons with which to resist the
attacks of his opponent, and who cannot detect the latent dialectic
which lies in his own opinions as well as in those of the opposite
party, sees the advance of illusory arguments and grounds of proof
which have the advantage of novelty, against as illusory grounds of
proof destitute of this advantage, and which, perhaps, excite the
suspicion that the natural credulity of his youth has been abused by
his instructors. He thinks he can find no better means of showing that
he has out grown the discipline of his minority than by despising those
well-meant warnings, and, knowing no system of thought but that of
dogmatism, he drinks deep draughts of the poison that is to sap the
principles in which his early years were trained.
Exactly the opposite of the system here recommended ought to be pursued
in academical instruction. This can only be effected, however, by a
thorough training in the critical investigation of pure reason. For, in
order to bring the principles of this critique into exercise as soon as
possible, and to demonstrate their perfect even in the presence of the
highest degree of dialectical illusion, the student ought to examine
the assertions made on both sides of speculative questions step by
step, and to test them by these principles. It cannot be a difficult
task for him to show the fallacies inherent in these propositions, and
thus he begins early to feel his own power of securing himself against
the influence of such sophistical arguments, which must finally lose,
for him, all their illusory power. And, although the same blows which
overturn the edifice of his opponent are as fatal to his own
speculative structures, if such he has wished to rear; he need not feel
any sorrow in regard to this seeming misfortune, as he has now before
him a fair prospect into the practical region in which he may
reasonably hope to find a more secure foundation for a rational system.
There is, accordingly, no proper polemic in the sphere of pure reason.
Both parties beat the air and fight with their own shadows, as they
pass beyond the limits of nature, and can find no tangible point of
attack—no firm footing for their dogmatical conflict. Fight as
vigorously as they may, the shadows which they hew down, immediately
start up again, like the heroes in Walhalla, and renew the bloodless
and unceasing contest.
But neither can we admit that there is any proper sceptical employment
of pure reason, such as might be based upon the principle of neutrality
in all speculative disputes. To excite reason against itself, to place
weapons in the hands of the party on the one side as well as in those
of the other, and to remain an undisturbed and sarcastic spectator of
the fierce struggle that ensues, seems, from the dogmatical point of
view, to be a part fitting only a malevolent disposition. But, when the
sophist evidences an invincible obstinacy and blindness, and a pride
which no criticism can moderate, there is no other practicable course
than to oppose to this pride and obstinacy similar feelings and
pretensions on the other side, equally well or ill founded, so that
reason, staggered by the reflections thus forced upon it, finds it
necessary to moderate its confidence in such pretensions and to listen
to the advice of criticism. But we cannot stop at these doubts, much
less regard the conviction of our ignorance, not only as a cure for the
conceit natural to dogmatism, but as the settlement of the disputes in
which reason is involved with itself. On the contrary, scepticism is
merely a means of awakening reason from its dogmatic dreams and
exciting it to a more careful investigation into its own powers and
pretensions. But, as scepticism appears to be the shortest road to a
permanent peace in the domain of philosophy, and as it is the track
pursued by the many who aim at giving a philosophical colouring to
their contemptuous dislike of all inquiries of this kind, I think it
necessary to present to my readers this mode of thought in its true
light.
_Scepticism not a Permanent State for Human Reason._
The consciousness of ignorance—unless this ignorance is recognized to
be absolutely necessary ought, instead of forming the conclusion of my
inquiries, to be the strongest motive to the pursuit of them. All
ignorance is either ignorance of things or of the limits of knowledge.
If my ignorance is accidental and not necessary, it must incite me, in
the first case, to a dogmatical inquiry regarding the objects of which
I am ignorant; in the second, to a critical investigation into the
bounds of all possible knowledge. But that my ignorance is absolutely
necessary and unavoidable, and that it consequently absolves from the
duty of all further investigation, is a fact which cannot be made out
upon empirical grounds—from observation—but upon critical grounds
alone, that is, by a thoroughgoing investigation into the primary
sources of cognition. It follows that the determination of the bounds
of reason can be made only on à priori grounds; while the empirical
limitation of reason, which is merely an indeterminate cognition of an
ignorance that can never be completely removed, can take place only à
posteriori. In other words, our empirical knowledge is limited by that
which yet remains for us to know. The former cognition of our
ignorance, which is possible only on a rational basis, is a science;
the latter is merely a perception, and we cannot say how far the
inferences drawn from it may extend. If I regard the earth, as it
really appears to my senses, as a flat surface, I am ignorant how far
this surface extends. But experience teaches me that, how far soever I
go, I always see before me a space in which I can proceed farther; and
thus I know the limits—merely visual—of my actual knowledge of the
earth, although I am ignorant of the limits of the earth itself. But if
I have got so far as to know that the earth is a sphere, and that its
surface is spherical, I can cognize à priori and determine upon
principles, from my knowledge of a small part of this surface—say to
the extent of a degree—the diameter and circumference of the earth; and
although I am ignorant of the objects which this surface contains, I
have a perfect knowledge of its limits and extent.
The sum of all the possible objects of our cognition seems to us to be
a level surface, with an apparent horizon—that which forms the limit of
its extent, and which has been termed by us the idea of unconditioned
totality. To reach this limit by empirical means is impossible, and all
attempts to determine it à priori according to a principle, are alike
in vain. But all the questions raised by pure reason relate to that
which lies beyond this horizon, or, at least, in its boundary line.
The celebrated David Hume was one of those geographers of human reason
who believe that they have given a sufficient answer to all such
questions by declaring them to lie beyond the horizon of our
knowledge—a horizon which, however, Hume was unable to determine. His
attention especially was directed to the principle of causality; and he
remarked with perfect justice that the truth of this principle, and
even the objective validity of the conception of a cause, was not
commonly based upon clear insight, that is, upon à priori cognition.
Hence he concluded that this law does not derive its authority from its
universality and necessity, but merely from its general applicability
in the course of experience, and a kind of subjective necessity thence
arising, which he termed habit. From the inability of reason to
establish this principle as a necessary law for the acquisition of all
experience, he inferred the nullity of all the attempts of reason to
pass the region of the empirical.
This procedure of subjecting the facta of reason to examination, and,
if necessary, to disapproval, may be termed the censura of reason. This
censura must inevitably lead us to doubts regarding all transcendent
employment of principles. But this is only the second step in our
inquiry. The first step in regard to the subjects of pure reason, and
which marks the infancy of that faculty, is that of dogmatism. The
second, which we have just mentioned, is that of scepticism, and it
gives evidence that our judgement has been improved by experience. But
a third step is necessary—indicative of the maturity and manhood of the
judgement, which now lays a firm foundation upon universal and
necessary principles. This is the period of criticism, in which we do
not examine the facta of reason, but reason itself, in the whole extent
of its powers, and in regard to its capability of à priori cognition;
and thus we determine not merely the empirical and ever-shifting bounds
of our knowledge, but its necessary and eternal limits. We demonstrate
from indubitable principles, not merely our ignorance in respect to
this or that subject, but in regard to all possible questions of a
certain class. Thus scepticism is a resting place for reason, in which
it may reflect on its dogmatical wanderings and gain some knowledge of
the region in which it happens to be, that it may pursue its way with
greater certainty; but it cannot be its permanent dwelling-place. It
must take up its abode only in the region of complete certitude,
whether this relates to the cognition of objects themselves, or to the
limits which bound all our cognition.
Reason is not to be considered as an indefinitely extended plane, of
the bounds of which we have only a general knowledge; it ought rather
to be compared to a sphere, the radius of which may be found from the
curvature of its surface—that is, the nature of à priori synthetical
propositions—and, consequently, its circumference and extent. Beyond
the sphere of experience there are no objects which it can cognize;
nay, even questions regarding such supposititious objects relate only
to the subjective principles of a complete determination of the
relations which exist between the understanding-conceptions which lie
within this sphere.
We are actually in possession of à priori synthetical cognitions, as is
proved by the existence of the principles of the understanding, which
anticipate experience. If any one cannot comprehend the possibility of
these principles, he may have some reason to doubt whether they are
really à priori; but he cannot on this account declare them to be
impossible, and affirm the nullity of the steps which reason may have
taken under their guidance. He can only say: If we perceived their
origin and their authenticity, we should be able to determine the
extent and limits of reason; but, till we can do this, all propositions
regarding the latter are mere random assertions. In this view, the
doubt respecting all dogmatical philosophy, which proceeds without the
guidance of criticism, is well grounded; but we cannot therefore deny
to reason the ability to construct a sound philosophy, when the way has
been prepared by a thorough critical investigation. All the conceptions
produced, and all the questions raised, by pure reason, do not lie in
the sphere of experience, but in that of reason itself, and hence they
must be solved, and shown to be either valid or inadmissible, by that
faculty. We have no right to decline the solution of such problems, on
the ground that the solution can be discovered only from the nature of
things, and under pretence of the limitation of human faculties, for
reason is the sole creator of all these ideas, and is therefore bound
either to establish their validity or to expose their illusory nature.
The polemic of scepticism is properly directed against the dogmatist,
who erects a system of philosophy without having examined the
fundamental objective principles on which it is based, for the purpose
of evidencing the futility of his designs, and thus bringing him to a
knowledge of his own powers. But, in itself, scepticism does not give
us any certain information in regard to the bounds of our knowledge.
All unsuccessful dogmatical attempts of reason are facia, which it is
always useful to submit to the censure of the sceptic. But this cannot
help us to any decision regarding the expectations which reason
cherishes of better success in future endeavours; the investigations of
scepticism cannot, therefore, settle the dispute regarding the rights
and powers of human reason.
Hume is perhaps the ablest and most ingenious of all sceptical
philosophers, and his writings have, undoubtedly, exerted the most
powerful influence in awakening reason to a thorough investigation into
its own powers. It will, therefore, well repay our labours to consider
for a little the course of reasoning which he followed and the errors
into which he strayed, although setting out on the path of truth and
certitude.
Hume was probably aware, although he never clearly developed the
notion, that we proceed in judgements of a certain class beyond our
conception of the object. I have termed this kind of judgement
synthetical. As regard the manner in which I pass beyond my conception
by the aid of experience, no doubts can be entertained. Experience is
itself a synthesis of perceptions; and it employs perceptions to
increment the conception, which I obtain by means of another
perception. But we feel persuaded that we are able to proceed beyond a
conception, and to extend our cognition à priori. We attempt this in
two ways—either, through the pure understanding, in relation to that
which may become an object of experience, or, through pure reason, in
relation to such properties of things, or of the existence of things,
as can never be presented in any experience. This sceptical philosopher
did not distinguish these two kinds of judgements, as he ought to have
done, but regarded this augmentation of conceptions, and, if we may so
express ourselves, the spontaneous generation of understanding and
reason, independently of the impregnation of experience, as altogether
impossible. The so-called à priori principles of these faculties he
consequently held to be invalid and imaginary, and regarded them as
nothing but subjective habits of thought originating in experience, and
therefore purely empirical and contingent rules, to which we attribute
a spurious necessity and universality. In support of this strange
assertion, he referred us to the generally acknowledged principle of
the relation between cause and effect. No faculty of the mind can
conduct us from the conception of a thing to the existence of something
else; and hence he believed he could infer that, without experience, we
possess no source from which we can augment a conception, and no ground
sufficient to justify us in framing a judgement that is to extend our
cognition à priori. That the light of the sun, which shines upon a
piece of wax, at the same time melts it, while it hardens clay, no
power of the understanding could infer from the conceptions which we
previously possessed of these substances; much less is there any à
priori law that could conduct us to such a conclusion, which experience
alone can certify. On the other hand, we have seen in our discussion of
transcendental logic, that, although we can never proceed immediately
beyond the content of the conception which is given us, we can always
cognize completely à priori—in relation, however, to a third term,
namely, possible experience—the law of its connection with other
things. For example, if I observe that a piece of wax melts, I can
cognize à priori that there must have been something (the sun’s heat)
preceding, which this law; although, without the aid of experience, I
could not cognize à priori and in a determinate manner either the cause
from the effect, or the effect from the cause. Hume was, therefore,
wrong in inferring, from the contingency of the determination according
to law, the contingency of the law itself; and the passing beyond the
conception of a thing to possible experience (which is an à priori
proceeding, constituting the objective reality of the conception), he
confounded with our synthesis of objects in actual experience, which is
always, of course, empirical. Thus, too, he regarded the principle of
affinity, which has its seat in the understanding and indicates a
necessary connection, as a mere rule of association, lying in the
imitative faculty of imagination, which can present only contingent,
and not objective connections.
The sceptical errors of this remarkably acute thinker arose principally
from a defect, which was common to him with the dogmatists, namely,
that he had never made a systematic review of all the different kinds
of à priori synthesis performed by the understanding. Had he done so,
he would have found, to take one example among many, that the principle
of permanence was of this character, and that it, as well as the
principle of causality, anticipates experience. In this way he might
have been able to describe the determinate limits of the à priori
operations of understanding and reason. But he merely declared the
understanding to be limited, instead of showing what its limits were;
he created a general mistrust in the power of our faculties, without
giving us any determinate knowledge of the bounds of our necessary and
unavoidable ignorance; he examined and condemned some of the principles
of the understanding, without investigating all its powers with the
completeness necessary to criticism. He denies, with truth, certain
powers to the understanding, but he goes further, and declares it to be
utterly inadequate to the à priori extension of knowledge, although he
has not fully examined all the powers which reside in the faculty; and
thus the fate which always overtakes scepticism meets him too. That is
to say, his own declarations are doubted, for his objections were based
upon facta, which are contingent, and not upon principles, which can
alone demonstrate the necessary invalidity of all dogmatical
assertions.
As Hume makes no distinction between the well-grounded claims of the
understanding and the dialectical pretensions of reason, against which,
however, his attacks are mainly directed, reason does not feel itself
shut out from all attempts at the extension of à priori cognition, and
hence it refuses, in spite of a few checks in this or that quarter, to
relinquish such efforts. For one naturally arms oneself to resist an
attack, and becomes more obstinate in the resolve to establish the
claims he has advanced. But a complete review of the powers of reason,
and the conviction thence arising that we are in possession of a
limited field of action, while we must admit the vanity of higher
claims, puts an end to all doubt and dispute, and induces reason to
rest satisfied with the undisturbed possession of its limited domain.
To the uncritical dogmatist, who has not surveyed the sphere of his
understanding, nor determined, in accordance with principles, the
limits of possible cognition, who, consequently, is ignorant of his own
powers, and believes he will discover them by the attempts he makes in
the field of cognition, these attacks of scepticism are not only
dangerous, but destructive. For if there is one proposition in his
chain of reasoning which he cannot prove, or the fallacy in which he
cannot evolve in accordance with a principle, suspicion falls on all
his statements, however plausible they may appear.
And thus scepticism, the bane of dogmatical philosophy, conducts us to
a sound investigation into the understanding and the reason. When we
are thus far advanced, we need fear no further attacks; for the limits
of our domain are clearly marked out, and we can make no claims nor
become involved in any disputes regarding the region that lies beyond
these limits. Thus the sceptical procedure in philosophy does not
present any solution of the problems of reason, but it forms an
excellent exercise for its powers, awakening its circumspection, and
indicating the means whereby it may most fully establish its claims to
its legitimate possessions.
Section III. The Discipline of Pure Reason in Hypothesis
This critique of reason has now taught us that all its efforts to
extend the bounds of knowledge, by means of pure speculation, are
utterly fruitless. So much the wider field, it may appear, lies open to
hypothesis; as, where we cannot know with certainty, we are at liberty
to make guesses and to form suppositions.
Imagination may be allowed, under the strict surveillance of reason, to
invent suppositions; but, these must be based on something that is
perfectly certain—and that is the possibility of the object. If we are
well assured upon this point, it is allowable to have recourse to
supposition in regard to the reality of the object; but this
supposition must, unless it is utterly groundless, be connected, as its
ground of explanation, with that which is really given and absolutely
certain. Such a supposition is termed a hypothesis.
It is beyond our power to form the least conception à priori of the
possibility of dynamical connection in phenomena; and the category of
the pure understanding will not enable us to excogitate any such
connection, but merely helps us to understand it, when we meet with it
in experience. For this reason we cannot, in accordance with the
categories, imagine or invent any object or any property of an object
not given, or that may not be given in experience, and employ it in a
hypothesis; otherwise, we should be basing our chain of reasoning upon
mere chimerical fancies, and not upon conceptions of things. Thus, we
have no right to assume the existence of new powers, not existing in
nature—for example, an understanding with a non-sensuous intuition, a
force of attraction without contact, or some new kind of substances
occupying space, and yet without the property of impenetrability—and,
consequently, we cannot assume that there is any other kind of
community among substances than that observable in experience, any kind
of presence than that in space, or any kind of duration than that in
time. In one word, the conditions of possible experience are for reason
the only conditions of the possibility of things; reason cannot venture
to form, independently of these conditions, any conceptions of things,
because such conceptions, although not self-contradictory, are without
object and without application.