The conceptions of reason are, as we have already shown, mere ideas,

and do not relate to any object in any kind of experience. At the same

time, they do not indicate imaginary or possible objects. They are

purely problematical in their nature and, as aids to the heuristic

exercise of the faculties, form the basis of the regulative principles

for the systematic employment of the understanding in the field of

experience. If we leave this ground of experience, they become mere

fictions of thought, the possibility of which is quite indemonstrable;

and they cannot, consequently, be employed as hypotheses in the

explanation of real phenomena. It is quite admissible to cogitate the

soul as simple, for the purpose of enabling ourselves to employ the

idea of a perfect and necessary unity of all the faculties of the mind

as the principle of all our inquiries into its internal phenomena,

although we cannot cognize this unity in concreto. But to assume that

the soul is a simple substance (a transcendental conception) would be

enouncing a proposition which is not only indemonstrable—as many

physical hypotheses are—but a proposition which is purely arbitrary,

and in the highest degree rash. The simple is never presented in

experience; and, if by substance is here meant the permanent object of

sensuous intuition, the possibility of a simple phenomenon is perfectly

inconceivable. Reason affords no good grounds for admitting the

existence of intelligible beings, or of intelligible properties of

sensuous things, although—as we have no conception either of their

possibility or of their impossibility—it will always be out of our

power to affirm dogmatically that they do not exist. In the explanation

of given phenomena, no other things and no other grounds of explanation

can be employed than those which stand in connection with the given

phenomena according to the known laws of experience. A transcendental

hypothesis, in which a mere idea of reason is employed to explain the

phenomena of nature, would not give us any better insight into a

phenomenon, as we should be trying to explain what we do not

sufficiently understand from known empirical principles, by what we do

not understand at all. The principles of such a hypothesis might

conduce to the satisfaction of reason, but it would not assist the

understanding in its application to objects. Order and conformity to

aims in the sphere of nature must be themselves explained upon natural

grounds and according to natural laws; and the wildest hypotheses, if

they are only physical, are here more admissible than a hyperphysical

hypothesis, such as that of a divine author. For such a hypothesis

would introduce the principle of ignava ratio, which requires us to

give up the search for causes that might be discovered in the course of

experience and to rest satisfied with a mere idea. As regards the

absolute totality of the grounds of explanation in the series of these

causes, this can be no hindrance to the understanding in the case of

phenomena; because, as they are to us nothing more than phenomena, we

have no right to look for anything like completeness in the synthesis

of the series of their conditions.

Transcendental hypotheses are therefore inadmissible; and we cannot use

the liberty of employing, in the absence of physical, hyperphysical

grounds of explanation. And this for two reasons; first, because such

hypothesis do not advance reason, but rather stop it in its progress;

secondly, because this licence would render fruitless all its exertions

in its own proper sphere, which is that of experience. For, when the

explanation of natural phenomena happens to be difficult, we have

constantly at hand a transcendental ground of explanation, which lifts

us above the necessity of investigating nature; and our inquiries are

brought to a close, not because we have obtained all the requisite

knowledge, but because we abut upon a principle which is

incomprehensible and which, indeed, is so far back in the track of

thought as to contain the conception of the absolutely primal being.

The next requisite for the admissibility of a hypothesis is its

sufficiency. That is, it must determine à priori the consequences which

are given in experience and which are supposed to follow from the

hypothesis itself. If we require to employ auxiliary hypotheses, the

suspicion naturally arises that they are mere fictions; because the

necessity for each of them requires the same justification as in the

case of the original hypothesis, and thus their testimony is invalid.

If we suppose the existence of an infinitely perfect cause, we possess

sufficient grounds for the explanation of the conformity to aims, the

order and the greatness which we observe in the universe; but we find

ourselves obliged, when we observe the evil in the world and the

exceptions to these laws, to employ new hypothesis in support of the

original one. We employ the idea of the simple nature of the human soul

as the foundation of all the theories we may form of its phenomena; but

when we meet with difficulties in our way, when we observe in the soul

phenomena similar to the changes which take place in matter, we require

to call in new auxiliary hypotheses. These may, indeed, not be false,

but we do not know them to be true, because the only witness to their

certitude is the hypothesis which they themselves have been called in

to explain.

We are not discussing the above-mentioned assertions regarding the

immaterial unity of the soul and the existence of a Supreme Being as

dogmata, which certain philosophers profess to demonstrate à priori,

but purely as hypotheses. In the former case, the dogmatist must take

care that his arguments possess the apodeictic certainty of a

demonstration. For the assertion that the reality of such ideas is

probable is as absurd as a proof of the probability of a proposition in

geometry. Pure abstract reason, apart from all experience, can either

cognize nothing at all; and hence the judgements it enounces are never

mere opinions, they are either apodeictic certainties, or declarations

that nothing can be known on the subject. Opinions and probable

judgements on the nature of things can only be employed to explain

given phenomena, or they may relate to the effect, in accordance with

empirical laws, of an actually existing cause. In other words, we must

restrict the sphere of opinion to the world of experience and nature.

Beyond this region opinion is mere invention; unless we are groping

about for the truth on a path not yet fully known, and have some hopes

of stumbling upon it by chance.

But, although hypotheses are inadmissible in answers to the questions

of pure speculative reason, they may be employed in the defence of

these answers. That is to say, hypotheses are admissible in polemic,

but not in the sphere of dogmatism. By the defence of statements of

this character, I do not mean an attempt at discovering new grounds for

their support, but merely the refutation of the arguments of opponents.

All à priori synthetical propositions possess the peculiarity that,

although the philosopher who maintains the reality of the ideas

contained in the proposition is not in possession of sufficient

knowledge to establish the certainty of his statements, his opponent is

as little able to prove the truth of the opposite. This equality of

fortune does not allow the one party to be superior to the other in the

sphere of speculative cognition; and it is this sphere, accordingly,

that is the proper arena of these endless speculative conflicts. But we

shall afterwards show that, in relation to its practical exercise,

Reason has the right of admitting what, in the field of pure

speculation, she would not be justified in supposing, except upon

perfectly sufficient grounds; because all such suppositions destroy the

necessary completeness of speculation—a condition which the practical

reason, however, does not consider to be requisite. In this sphere,

therefore, Reason is mistress of a possession, her title to which she

does not require to prove—which, in fact, she could not do. The burden

of proof accordingly rests upon the opponent. But as he has just as

little knowledge regarding the subject discussed, and is as little able

to prove the non-existence of the object of an idea, as the philosopher

on the other side is to demonstrate its reality, it is evident that

there is an advantage on the side of the philosopher who maintains his

proposition as a practically necessary supposition (melior est conditio

possidentis). For he is at liberty to employ, in self-defence, the same

weapons as his opponent makes use of in attacking him; that is, he has

a right to use hypotheses not for the purpose of supporting the

arguments in favour of his own propositions, but to show that his

opponent knows no more than himself regarding the subject under

discussion and cannot boast of any speculative advantage.

Hypotheses are, therefore, admissible in the sphere of pure reason only

as weapons for self-defence, and not as supports to dogmatical

assertions. But the opposing party we must always seek for in

ourselves. For speculative reason is, in the sphere of

transcendentalism, dialectical in its own nature. The difficulties and

objections we have to fear lie in ourselves. They are like old but

never superannuated claims; and we must seek them out, and settle them

once and for ever, if we are to expect a permanent peace. External

tranquility is hollow and unreal. The root of these contradictions,

which lies in the nature of human reason, must be destroyed; and this

can only be done by giving it, in the first instance, freedom to grow,

nay, by nourishing it, that it may send out shoots, and thus betray its

own existence. It is our duty, therefore, to try to discover new

objections, to put weapons in the bands of our opponent, and to grant

him the most favourable position in the arena that he can wish. We have

nothing to fear from these concessions; on the contrary, we may rather

hope that we shall thus make ourselves master of a possession which no

one will ever venture to dispute.

The thinker requires, to be fully equipped, the hypotheses of pure

reason, which, although but leaden weapons (for they have not been

steeled in the armoury of experience), are as useful as any that can be

employed by his opponents. If, accordingly, we have assumed, from a

non-speculative point of view, the immaterial nature of the soul, and

are met by the objection that experience seems to prove that the growth

and decay of our mental faculties are mere modifications of the

sensuous organism—we can weaken the force of this objection by the

assumption that the body is nothing but the fundamental phenomenon, to

which, as a necessary condition, all sensibility, and consequently all

thought, relates in the present state of our existence; and that the

separation of soul and body forms the conclusion of the sensuous

exercise of our power of cognition and the beginning of the

intellectual. The body would, in this view of the question, be

regarded, not as the cause of thought, but merely as its restrictive

condition, as promotive of the sensuous and animal, but as a hindrance

to the pure and spiritual life; and the dependence of the animal life

on the constitution of the body, would not prove that the whole life of

man was also dependent on the state of the organism. We might go still

farther, and discover new objections, or carry out to their extreme

consequences those which have already been adduced.

Generation, in the human race as well as among the irrational animals,

depends on so many accidents—of occasion, of proper sustenance, of the

laws enacted by the government of a country of vice even, that it is

difficult to believe in the eternal existence of a being whose life has

begun under circumstances so mean and trivial, and so entirely

dependent upon our own control. As regards the continuance of the

existence of the whole race, we need have no difficulties, for accident

in single cases is subject to general laws; but, in the case of each

individual, it would seem as if we could hardly expect so wonderful an

effect from causes so insignificant. But, in answer to these

objections, we may adduce the transcendental hypothesis that all life

is properly intelligible, and not subject to changes of time, and that

it neither began in birth, nor will end in death. We may assume that

this life is nothing more than a sensuous representation of pure

spiritual life; that the whole world of sense is but an image, hovering

before the faculty of cognition which we exercise in this sphere, and

with no more objective reality than a dream; and that if we could

intuite ourselves and other things as they really are, we should see

ourselves in a world of spiritual natures, our connection with which

did not begin at our birth and will not cease with the destruction of

the body. And so on.

We cannot be said to know what has been above asserted, nor do we

seriously maintain the truth of these assertions; and the notions

therein indicated are not even ideas of reason, they are purely

fictitious conceptions. But this hypothetical procedure is in perfect

conformity with the laws of reason. Our opponent mistakes the absence

of empirical conditions for a proof of the complete impossibility of

all that we have asserted; and we have to show him that he has not

exhausted the whole sphere of possibility and that he can as little

compass that sphere by the laws of experience and nature, as we can lay

a secure foundation for the operations of reason beyond the region of

experience. Such hypothetical defences against the pretensions of an

opponent must not be regarded as declarations of opinion. The

philosopher abandons them, so soon as the opposite party renounces its

dogmatical conceit. To maintain a simply negative position in relation

to propositions which rest on an insecure foundation, well befits the

moderation of a true philosopher; but to uphold the objections urged

against an opponent as proofs of the opposite statement is a proceeding

just as unwarrantable and arrogant as it is to attack the position of a

philosopher who advances affirmative propositions regarding such a

subject.

It is evident, therefore, that hypotheses, in the speculative sphere,

are valid, not as independent propositions, but only relatively to

opposite transcendent assumptions. For, to make the principles of

possible experience conditions of the possibility of things in general

is just as transcendent a procedure as to maintain the objective

reality of ideas which can be applied to no objects except such as lie

without the limits of possible experience. The judgements enounced by

pure reason must be necessary, or they must not be enounced at all.

Reason cannot trouble herself with opinions. But the hypotheses we have

been discussing are merely problematical judgements, which can neither

be confuted nor proved; while, therefore, they are not personal

opinions, they are indispensable as answers to objections which are

liable to be raised. But we must take care to confine them to this

function, and guard against any assumption on their part of absolute

validity, a proceeding which would involve reason in inextricable

difficulties and contradictions.

Section IV. The Discipline of Pure Reason in Relation to Proofs

It is a peculiarity, which distinguishes the proofs of transcendental

synthetical propositions from those of all other à priori synthetical

cognitions, that reason, in the case of the former, does not apply its

conceptions directly to an object, but is first obliged to prove, à

priori, the objective validity of these conceptions and the possibility

of their syntheses. This is not merely a prudential rule, it is

essential to the very possibility of the proof of a transcendental

proposition. If I am required to pass, à priori, beyond the conception

of an object, I find that it is utterly impossible without the guidance

of something which is not contained in the conception. In mathematics,

it is à priori intuition that guides my synthesis; and, in this case,

all our conclusions may be drawn immediately from pure intuition. In

transcendental cognition, so long as we are dealing only with

conceptions of the understanding, we are guided by possible experience.

That is to say, a proof in the sphere of transcendental cognition does

not show that the given conception (that of an event, for example)

leads directly to another conception (that of a cause)—for this would

be a saltus which nothing can justify; but it shows that experience

itself, and consequently the object of experience, is impossible

without the connection indicated by these conceptions. It follows that

such a proof must demonstrate the possibility of arriving,

synthetically and à priori, at a certain knowledge of things, which was

not contained in our conceptions of these things. Unless we pay

particular attention to this requirement, our proofs, instead of

pursuing the straight path indicated by reason, follow the tortuous

road of mere subjective association. The illusory conviction, which

rests upon subjective causes of association, and which is considered as

resulting from the perception of a real and objective natural affinity,

is always open to doubt and suspicion. For this reason, all the

attempts which have been made to prove the principle of sufficient

reason, have, according to the universal admission of philosophers,

been quite unsuccessful; and, before the appearance of transcendental

criticism, it was considered better, as this principle could not be

abandoned, to appeal boldly to the common sense of mankind (a

proceeding which always proves that the problem, which reason ought to

solve, is one in which philosophers find great difficulties), rather

than attempt to discover new dogmatical proofs.

But, if the proposition to be proved is a proposition of pure reason,

and if I aim at passing beyond my empirical conceptions by the aid of

mere ideas, it is necessary that the proof should first show that such

a step in synthesis is possible (which it is not), before it proceeds

to prove the truth of the proposition itself. The so-called proof of

the simple nature of the soul from the unity of apperception, is a very

plausible one. But it contains no answer to the objection, that, as the

notion of absolute simplicity is not a conception which is directly

applicable to a perception, but is an idea which must be inferred—if at

all—from observation, it is by no means evident how the mere fact of

consciousness, which is contained in all thought, although in so far a

simple representation, can conduct me to the consciousness and

cognition of a thing which is purely a thinking substance. When I

represent to my mind the power of my body as in motion, my body in this

thought is so far absolute unity, and my representation of it is a

simple one; and hence I can indicate this representation by the motion

of a point, because I have made abstraction of the size or volume of

the body. But I cannot hence infer that, given merely the moving power

of a body, the body may be cogitated as simple substance, merely

because the representation in my mind takes no account of its content

in space, and is consequently simple. The simple, in abstraction, is

very different from the objectively simple; and hence the Ego, which is

simple in the first sense, may, in the second sense, as indicating the

soul itself, be a very complex conception, with a very various content.

Thus it is evident that in all such arguments there lurks a paralogism.

We guess (for without some such surmise our suspicion would not be

excited in reference to a proof of this character) at the presence of

the paralogism, by keeping ever before us a criterion of the

possibility of those synthetical propositions which aim at proving more

than experience can teach us. This criterion is obtained from the

observation that such proofs do not lead us directly from the subject

of the proposition to be proved to the required predicate, but find it

necessary to presuppose the possibility of extending our cognition à

priori by means of ideas. We must, accordingly, always use the greatest

caution; we require, before attempting any proof, to consider how it is

possible to extend the sphere of cognition by the operations of pure

reason, and from what source we are to derive knowledge, which is not

obtained from the analysis of conceptions, nor relates, by

anticipation, to possible experience. We shall thus spare ourselves

much severe and fruitless labour, by not expecting from reason what is

beyond its power, or rather by subjecting it to discipline, and

teaching it to moderate its vehement desires for the extension of the

sphere of cognition.

The first rule for our guidance is, therefore, not to attempt a

transcendental proof, before we have considered from what source we are

to derive the principles upon which the proof is to be based, and what

right we have to expect that our conclusions from these principles will

be veracious. If they are principles of the understanding, it is vain

to expect that we should attain by their means to ideas of pure reason;

for these principles are valid only in regard to objects of possible

experience. If they are principles of pure reason, our labour is alike

in vain. For the principles of reason, if employed as objective, are

without exception dialectical and possess no validity or truth, except

as regulative principles of the systematic employment of reason in

experience. But when such delusive proof are presented to us, it is our

duty to meet them with the non liquet of a matured judgement; and,

although we are unable to expose the particular sophism upon which the

proof is based, we have a right to demand a deduction of the principles

employed in it; and, if these principles have their origin in pure

reason alone, such a deduction is absolutely impossible. And thus it is

unnecessary that we should trouble ourselves with the exposure and

confutation of every sophistical illusion; we may, at once, bring all

dialectic, which is inexhaustible in the production of fallacies,

before the bar of critical reason, which tests the principles upon

which all dialectical procedure is based. The second peculiarity of

transcendental proof is that a transcendental proposition cannot rest

upon more than a single proof. If I am drawing conclusions, not from

conceptions, but from intuition corresponding to a conception, be it

pure intuition, as in mathematics, or empirical, as in natural science,

the intuition which forms the basis of my inferences presents me with

materials for many synthetical propositions, which I can connect in

various modes, while, as it is allowable to proceed from different

points in the intention, I can arrive by different paths at the same

proposition.

But every transcendental proposition sets out from a conception, and

posits the synthetical condition of the possibility of an object

according to this conception. There must, therefore, be but one ground

of proof, because it is the conception alone which determines the

object; and thus the proof cannot contain anything more than the

determination of the object according to the conception. In our

Transcendental Analytic, for example, we inferred the principle: Every

event has a cause, from the only condition of the objective possibility

of our conception of an event. This is that an event cannot be

determined in time, and consequently cannot form a part of experience,

unless it stands under this dynamical law. This is the only possible

ground of proof; for our conception of an event possesses objective

validity, that is, is a true conception, only because the law of

causality determines an object to which it can refer. Other arguments

in support of this principle have been attempted—such as that from the

contingent nature of a phenomenon; but when this argument is

considered, we can discover no criterion of contingency, except the

fact of an event—of something happening, that is to say, the existence

which is preceded by the non-existence of an object, and thus we fall

back on the very thing to be proved. If the proposition: “Every

thinking being is simple,” is to be proved, we keep to the conception

of the ego, which is simple, and to which all thought has a relation.

The same is the case with the transcendental proof of the existence of

a Deity, which is based solely upon the harmony and reciprocal fitness

of the conceptions of an ens realissimum and a necessary being, and

cannot be attempted in any other manner.

This caution serves to simplify very much the criticism of all

propositions of reason. When reason employs conceptions alone, only one

proof of its thesis is possible, if any. When, therefore, the dogmatist

advances with ten arguments in favour of a proposition, we may be sure

that not one of them is conclusive. For if he possessed one which

proved the proposition he brings forward to demonstration—as must

always be the case with the propositions of pure reason—what need is

there for any more? His intention can only be similar to that of the

advocate who had different arguments for different judges; this

availing himself of the weakness of those who examine his arguments,

who, without going into any profound investigation, adopt the view of

the case which seems most probable at first sight and decide according

to it.

The third rule for the guidance of pure reason in the conduct of a

proof is that all transcendental proofs must never be apagogic or

indirect, but always ostensive or direct. The direct or ostensive proof

not only establishes the truth of the proposition to be proved, but

exposes the grounds of its truth; the apagogic, on the other hand, may

assure us of the truth of the proposition, but it cannot enable us to

comprehend the grounds of its possibility. The latter is, accordingly,

rather an auxiliary to an argument, than a strictly philosophical and

rational mode of procedure. In one respect, however, they have an

advantage over direct proofs, from the fact that the mode of arguing by

contradiction, which they employ, renders our understanding of the

question more clear, and approximates the proof to the certainty of an

intuitional demonstration.

The true reason why indirect proofs are employed in different sciences

is this. When the grounds upon which we seek to base a cognition are

too various or too profound, we try whether or not we may not discover

the truth of our cognition from its consequences. The modus ponens of

reasoning from the truth of its inferences to the truth of a

proposition would be admissible if all the inferences that can be drawn

from it are known to be true; for in this case there can be only one

possible ground for these inferences, and that is the true one. But

this is a quite impracticable procedure, as it surpasses all our powers

to discover all the possible inferences that can be drawn from a

proposition. But this mode of reasoning is employed, under favour, when

we wish to prove the truth of an hypothesis; in which case we admit the

truth of the conclusion—which is supported by analogy—that, if all the

inferences we have drawn and examined agree with the proposition

assumed, all other possible inferences will also agree with it. But, in

this way, an hypothesis can never be established as a demonstrated

truth. The modus tollens of reasoning from known inferences to the

unknown proposition, is not only a rigorous, but a very easy mode of

proof. For, if it can be shown that but one inference from a

proposition is false, then the proposition must itself be false.

Instead, then, of examining, in an ostensive argument, the whole series

of the grounds on which the truth of a proposition rests, we need only

take the opposite of this proposition, and if one inference from it be

false, then must the opposite be itself false; and, consequently, the

proposition which we wished to prove must be true.

The apagogic method of proof is admissible only in those sciences where

it is impossible to mistake a subjective representation for an

objective cognition. Where this is possible, it is plain that the

opposite of a given proposition may contradict merely the subjective

conditions of thought, and not the objective cognition; or it may

happen that both propositions contradict each other only under a

subjective condition, which is incorrectly considered to be objective,

and, as the condition is itself false, both propositions may be false,

and it will, consequently, be impossible to conclude the truth of the

one from the falseness of the other.

In mathematics such subreptions are impossible; and it is in this

science, accordingly, that the indirect mode of proof has its true

place. In the science of nature, where all assertion is based upon

empirical intuition, such subreptions may be guarded against by the

repeated comparison of observations; but this mode of proof is of

little value in this sphere of knowledge. But the transcendental

efforts of pure reason are all made in the sphere of the subjective,

which is the real medium of all dialectical illusion; and thus reason

endeavours, in its premisses, to impose upon us subjective

representations for objective cognitions. In the transcendental sphere

of pure reason, then, and in the case of synthetical propositions, it

is inadmissible to support a statement by disproving the

counter-statement. For only two cases are possible; either, the

counter-statement is nothing but the enouncement of the inconsistency

of the opposite opinion with the subjective conditions of reason, which

does not affect the real case (for example, we cannot comprehend the

unconditioned necessity of the existence of a being, and hence every

speculative proof of the existence of such a being must be opposed on

subjective grounds, while the possibility of this being in itself

cannot with justice be denied); or, both propositions, being

dialectical in their nature, are based upon an impossible conception.

In this latter case the rule applies: non entis nulla sunt predicata;

that is to say, what we affirm and what we deny, respecting such an

object, are equally untrue, and the apagogic mode of arriving at the

truth is in this case impossible. If, for example, we presuppose that

the world of sense is given in itself in its totality, it is false,

either that it is infinite, or that it is finite and limited in space.

Both are false, because the hypothesis is false. For the notion of

phenomena (as mere representations) which are given in themselves (as

objects) is self-contradictory; and the infinitude of this imaginary

whole would, indeed, be unconditioned, but would be inconsistent (as

everything in the phenomenal world is conditioned) with the

unconditioned determination and finitude of quantities which is

presupposed in our conception.

The apagogic mode of proof is the true source of those illusions which

have always had so strong an attraction for the admirers of dogmatical

philosophy. It may be compared to a champion who maintains the honour

and claims of the party he has adopted by offering battle to all who

doubt the validity of these claims and the purity of that honour; while

nothing can be proved in this way, except the respective strength of

the combatants, and the advantage, in this respect, is always on the

side of the attacking party. Spectators, observing that each party is

alternately conqueror and conquered, are led to regard the subject of

dispute as beyond the power of man to decide upon. But such an opinion

cannot be justified; and it is sufficient to apply to these reasoners

the remark:

_Non defensoribus istis

Tempus eget._

Each must try to establish his assertions by a transcendental deduction

of the grounds of proof employed in his argument, and thus enable us to

see in what way the claims of reason may be supported. If an opponent

bases his assertions upon subjective grounds, he may be refuted with

ease; not, however to the advantage of the dogmatist, who likewise

depends upon subjective sources of cognition and is in like manner

driven into a corner by his opponent. But, if parties employ the direct

method of procedure, they will soon discover the difficulty, nay, the

impossibility of proving their assertions, and will be forced to appeal

to prescription and precedence; or they will, by the help of criticism,

discover with ease the dogmatical illusions by which they had been

mocked, and compel reason to renounce its exaggerated pretensions to

speculative insight and to confine itself within the limits of its

proper sphere—that of practical principles.

Chapter II. The Canon of Pure Reason

It is a humiliating consideration for human reason that it is

incompetent to discover truth by means of pure speculation, but, on the

contrary, stands in need of discipline to check its deviations from the

straight path and to expose the illusions which it originates. But, on

the other hand, this consideration ought to elevate and to give it

confidence, for this discipline is exercised by itself alone, and it is

subject to the censure of no other power. The bounds, moreover, which

it is forced to set to its speculative exercise, form likewise a check

upon the fallacious pretensions of opponents; and thus what remains of

its possessions, after these exaggerated claims have been disallowed,

is secure from attack or usurpation. The greatest, and perhaps the

only, use of all philosophy of pure reason is, accordingly, of a purely

negative character. It is not an organon for the extension, but a

discipline for the determination, of the limits of its exercise; and

without laying claim to the discovery of new truth, it has the modest

merit of guarding against error.

At the same time, there must be some source of positive cognitions

which belong to the domain of pure reason and which become the causes

of error only from our mistaking their true character, while they form

the goal towards which reason continually strives. How else can we

account for the inextinguishable desire in the human mind to find a

firm footing in some region beyond the limits of the world of

experience? It hopes to attain to the possession of a knowledge in

which it has the deepest interest. It enters upon the path of pure

speculation; but in vain. We have some reason, however, to expect that,

in the only other way that lies open to it—the path of practical

reason—it may meet with better success.

I understand by a canon a list of the à priori principles of the proper

employment of certain faculties of cognition. Thus general logic, in

its analytical department, is a formal canon for the faculties of

understanding and reason. In the same way, Transcendental Analytic was

seen to be a canon of the pure understanding; for it alone is competent

to enounce true à priori synthetical cognitions. But, when no proper

employment of a faculty of cognition is possible, no canon can exist.

But the synthetical cognition of pure speculative reason is, as has

been shown, completely impossible. There cannot, therefore, exist any

canon for the speculative exercise of this faculty—for its speculative

exercise is entirely dialectical; and, consequently, transcendental

logic, in this respect, is merely a discipline, and not a canon. If,

then, there is any proper mode of employing the faculty of pure

reason—in which case there must be a canon for this faculty—this canon

will relate, not to the speculative, but to the practical use of

reason. This canon we now proceed to investigate.

Section I. Of the Ultimate End of the Pure Use of Reason

There exists in the faculty of reason a natural desire to venture

beyond the field of experience, to attempt to reach the utmost bounds

of all cognition by the help of ideas alone, and not to rest satisfied

until it has fulfilled its course and raised the sum of its cognitions

into a self-subsistent systematic whole. Is the motive for this

endeavour to be found in its speculative, or in its practical interests

alone?

Setting aside, at present, the results of the labours of pure reason in

its speculative exercise, I shall merely inquire regarding the problems

the solution of which forms its ultimate aim, whether reached or not,

and in relation to which all other aims are but partial and

intermediate. These highest aims must, from the nature of reason,

possess complete unity; otherwise the highest interest of humanity

could not be successfully promoted.

The transcendental speculation of reason relates to three things: the

freedom of the will, the immortality of the soul, and the existence of

God. The speculative interest which reason has in those questions is

very small; and, for its sake alone, we should not undertake the labour

of transcendental investigation—a labour full of toil and ceaseless

struggle. We should be loth to undertake this labour, because the

discoveries we might make would not be of the smallest use in the

sphere of concrete or physical investigation. We may find out that the

will is free, but this knowledge only relates to the intelligible cause

of our volition. As regards the phenomena or expressions of this will,

that is, our actions, we are bound, in obedience to an inviolable

maxim, without which reason cannot be employed in the sphere of

experience, to explain these in the same way as we explain all the

other phenomena of nature, that is to say, according to its

unchangeable laws. We may have discovered the spirituality and

immortality of the soul, but we cannot employ this knowledge to explain

the phenomena of this life, nor the peculiar nature of the future,

because our conception of an incorporeal nature is purely negative and

does not add anything to our knowledge, and the only inferences to be

drawn from it are purely fictitious. If, again, we prove the existence

of a supreme intelligence, we should be able from it to make the

conformity to aims existing in the arrangement of the world

comprehensible; but we should not be justified in deducing from it any

particular arrangement or disposition, or inferring any where it is not

perceived. For it is a necessary rule of the speculative use of reason

that we must not overlook natural causes, or refuse to listen to the

teaching of experience, for the sake of deducing what we know and

perceive from something that transcends all our knowledge. In one word,

these three propositions are, for the speculative reason, always

transcendent, and cannot be employed as immanent principles in relation

to the objects of experience; they are, consequently, of no use to us

in this sphere, being but the valueless results of the severe but

unprofitable efforts of reason.

If, then, the actual cognition of these three cardinal propositions is

perfectly useless, while Reason uses her utmost endeavours to induce us

to admit them, it is plain that their real value and importance relate

to our practical, and not to our speculative interest.

I term all that is possible through free will, practical. But if the

conditions of the exercise of free volition are empirical, reason can

have only a regulative, and not a constitutive, influence upon it, and

is serviceable merely for the introduction of unity into its empirical

laws. In the moral philosophy of prudence, for example, the sole

business of reason is to bring about a union of all the ends, which are

aimed at by our inclinations, into one ultimate end—that of

happiness—and to show the agreement which should exist among the means

of attaining that end. In this sphere, accordingly, reason cannot

present to us any other than pragmatical laws of free action, for our

guidance towards the aims set up by the senses, and is incompetent to

give us laws which are pure and determined completely à priori. On the

other hand, pure practical laws, the ends of which have been given by

reason entirely à priori, and which are not empirically conditioned,

but are, on the contrary, absolutely imperative in their nature, would

be products of pure reason. Such are the moral laws; and these alone

belong to the sphere of the practical exercise of reason, and admit of

a canon.

All the powers of reason, in the sphere of what may be termed pure

philosophy, are, in fact, directed to the three above-mentioned

problems alone. These again have a still higher end—the answer to the

question, what we ought to do, if the will is free, if there is a God

and a future world. Now, as this problem relates to our in reference to

the highest aim of humanity, it is evident that the ultimate intention

of nature, in the constitution of our reason, has been directed to the

moral alone.

We must take care, however, in turning our attention to an object which

is foreign[78] to the sphere of transcendental philosophy, not to

injure the unity of our system by digressions, nor, on the other hand,

to fail in clearness, by saying too little on the new subject of

discussion. I hope to avoid both extremes, by keeping as close as

possible to the transcendental, and excluding all psychological, that

is, empirical, elements.

[78] All practical conceptions relate to objects of pleasure and pain,

and consequently—in an indirect manner, at least—to objects of

feeling. But as feeling is not a faculty of representation, but lies

out of the sphere of our powers of cognition, the elements of our

judgements, in so far as they relate to pleasure or pain, that is, the

elements of our practical judgements, do not belong to transcendental

philosophy, which has to do with pure à priori cognitions alone.

I have to remark, in the first place, that at present I treat of the

conception of freedom in the practical sense only, and set aside the

corresponding transcendental conception, which cannot be employed as a

ground of explanation in the phenomenal world, but is itself a problem

for pure reason. A will is purely animal (arbitrium brutum) when it is

determined by sensuous impulses or instincts only, that is, when it is

determined in a pathological manner. A will, which can be determined

independently of sensuous impulses, consequently by motives presented

by reason alone, is called a free will (arbitrium liberum); and

everything which is connected with this free will, either as principle

or consequence, is termed practical. The existence of practical freedom

can be proved from experience alone. For the human will is not

determined by that alone which immediately affects the senses; on the

contrary, we have the power, by calling up the notion of what is useful

or hurtful in a more distant relation, of overcoming the immediate

impressions on our sensuous faculty of desire. But these considerations

of what is desirable in relation to our whole state, that is, is in the

end good and useful, are based entirely upon reason. This faculty,

accordingly, enounces laws, which are imperative or objective laws of

freedom and which tell us what ought to take place, thus distinguishing

themselves from the laws of nature, which relate to that which does

take place. The laws of freedom or of free will are hence termed

practical laws.

Whether reason is not itself, in the actual delivery of these laws,

determined in its turn by other influences, and whether the action

which, in relation to sensuous impulses, we call free, may not, in

relation to higher and more remote operative causes, really form a part

of nature—these are questions which do not here concern us. They are

purely speculative questions; and all we have to do, in the practical

sphere, is to inquire into the rule of conduct which reason has to

present. Experience demonstrates to us the existence of practical

freedom as one of the causes which exist in nature, that is, it shows

the causal power of reason in the determination of the will. The idea

of transcendental freedom, on the contrary, requires that reason—in

relation to its causal power of commencing a series of phenomena—should

be independent of all sensuous determining causes; and thus it seems to

be in opposition to the law of nature and to all possible experience.

It therefore remains a problem for the human mind. But this problem

does not concern reason in its practical use; and we have, therefore,

in a canon of pure reason, to do with only two questions, which relate

to the practical interest of pure reason: Is there a God? and, Is there

a future life? The question of transcendental freedom is purely

speculative, and we may therefore set it entirely aside when we come to

treat of practical reason. Besides, we have already discussed this

subject in the antinomy of pure reason.

Section II. Of the Ideal of the Summum Bonum as a Determining Ground of

the Ultimate End of Pure Reason

Reason conducted us, in its speculative use, through the field of

experience and, as it can never find complete satisfaction in that

sphere, from thence to speculative ideas—which, however, in the end

brought us back again to experience, and thus fulfilled the purpose of

reason, in a manner which, though useful, was not at all in accordance

with our expectations. It now remains for us to consider whether pure

reason can be employed in a practical sphere, and whether it will here

conduct us to those ideas which attain the highest ends of pure reason,

as we have just stated them. We shall thus ascertain whether, from the

point of view of its practical interest, reason may not be able to

supply us with that which, on the speculative side, it wholly denies

us.

The whole interest of reason, speculative as well as practical, is

centred in the three following questions:

1. WHAT CAN I KNOW?

2. WHAT OUGHT I TO DO?

3. WHAT MAY I HOPE?

The first question is purely speculative. We have, as I flatter myself,

exhausted all the replies of which it is susceptible, and have at last

found the reply with which reason must content itself, and with which

it ought to be content, so long as it pays no regard to the practical.

But from the two great ends to the attainment of which all these

efforts of pure reason were in fact directed, we remain just as far

removed as if we had consulted our ease and declined the task at the

outset. So far, then, as knowledge is concerned, thus much, at least,

is established, that, in regard to those two problems, it lies beyond

our reach.

The second question is purely practical. As such it may indeed fall

within the province of pure reason, but still it is not transcendental,

but moral, and consequently cannot in itself form the subject of our

criticism.

The third question: If I act as I ought to do, what may I then hope?—is

at once practical and theoretical. The practical forms a clue to the

answer of the theoretical, and—in its highest form—speculative

question. For all hoping has happiness for its object and stands in

precisely the same relation to the practical and the law of morality as

knowing to the theoretical cognition of things and the law of nature.

The former arrives finally at the conclusion that something is (which

determines the ultimate end), because something ought to take place;

the latter, that something is (which operates as the highest cause),

because something does take place.

Happiness is the satisfaction of all our desires; extensive, in regard

to their multiplicity; intensive, in regard to their degree; and

protensive, in regard to their duration. The practical law based on the

motive of happiness I term a pragmatical law (or prudential rule); but

that law, assuming such to exist, which has no other motive than the

worthiness of being happy, I term a moral or ethical law. The first

tells us what we have to do, if we wish to become possessed of

happiness; the second dictates how we ought to act, in order to deserve

happiness. The first is based upon empirical principles; for it is only

by experience that I can learn either what inclinations exist which

desire satisfaction, or what are the natural means of satisfying them.

The second takes no account of our desires or the means of satisfying

them, and regards only the freedom of a rational being, and the

necessary conditions under which alone this freedom can harmonize with

the distribution of happiness according to principles. This second law

may therefore rest upon mere ideas of pure reason, and may be cognized

à priori.

I assume that there are pure moral laws which determine, entirely à

priori (without regard to empirical motives, that is, to happiness),

the conduct of a rational being, or in other words, to use which it

makes of its freedom, and that these laws are absolutely imperative

(not merely hypothetically, on the supposition of other empirical

ends), and therefore in all respects necessary. I am warranted in

assuming this, not only by the arguments of the most enlightened

moralists, but by the moral judgement of every man who will make the

attempt to form a distinct conception of such a law.

Pure reason, then, contains, not indeed in its speculative, but in its

practical, or, more strictly, its moral use, principles of the

possibility of experience, of such actions, namely, as, in accordance

with ethical precepts, might be met with in the history of man. For

since reason commands that such actions should take place, it must be

possible for them to take place; and hence a particular kind of

systematic unity—the moral—must be possible. We have found, it is true,

that the systematic unity of nature could not be established according

to speculative principles of reason, because, while reason possesses a

causal power in relation to freedom, it has none in relation to the

whole sphere of nature; and, while moral principles of reason can

produce free actions, they cannot produce natural laws. It is, then, in

its practical, but especially in its moral use, that the principles of

pure reason possess objective reality.

I call the world a moral world, in so far as it may be in accordance

with all the ethical laws—which, by virtue of the freedom of reasonable

beings, it can be, and according to the necessary laws of morality it

ought to be. But this world must be conceived only as an intelligible

world, inasmuch as abstraction is therein made of all conditions

(ends), and even of all impediments to morality (the weakness or

pravity of human nature). So far, then, it is a mere idea—though still

a practical idea—which may have, and ought to have, an influence on the

world of sense, so as to bring it as far as possible into conformity

with itself. The idea of a moral world has, therefore, objective

reality, not as referring to an object of intelligible intuition—for of

such an object we can form no conception whatever—but to the world of

sense—conceived, however, as an object of pure reason in its practical

use—and to a corpus mysticum of rational beings in it, in so far as the

liberum arbitrium of the individual is placed, under and by virtue of

moral laws, in complete systematic unity both with itself and with the

freedom of all others.

That is the answer to the first of the two questions of pure reason

which relate to its practical interest: Do that which will render thee

worthy of happiness. The second question is this: If I conduct myself

so as not to be unworthy of happiness, may I hope thereby to obtain

happiness? In order to arrive at the solution of this question, we must

inquire whether the principles of pure reason, which prescribe à priori

the law, necessarily also connect this hope with it.

I say, then, that just as the moral principles are necessary according

to reason in its practical use, so it is equally necessary according to

reason in its theoretical use to assume that every one has ground to

hope for happiness in the measure in which he has made himself worthy

of it in his conduct, and that therefore the system of morality is

inseparably (though only in the idea of pure reason) connected with

that of happiness.

Now in an intelligible, that is, in the moral world, in the conception

of which we make abstraction of all the impediments to morality

(sensuous desires), such a system of happiness, connected with and

proportioned to morality, may be conceived as necessary, because

freedom of volition—partly incited, and partly restrained by moral

laws—would be itself the cause of general happiness; and thus rational

beings, under the guidance of such principles, would be themselves the

authors both of their own enduring welfare and that of others. But such

a system of self-rewarding morality is only an idea, the carrying out

of which depends upon the condition that every one acts as he ought; in

other words, that all actions of reasonable beings be such as they

would be if they sprung from a Supreme Will, comprehending in, or

under, itself all particular wills. But since the moral law is binding

on each individual in the use of his freedom of volition, even if

others should not act in conformity with this law, neither the nature

of things, nor the causality of actions and their relation to morality,

determine how the consequences of these actions will be related to

happiness; and the necessary connection of the hope of happiness with

the unceasing endeavour to become worthy of happiness, cannot be

cognized by reason, if we take nature alone for our guide. This

connection can be hoped for only on the assumption that the cause of

nature is a supreme reason, which governs according to moral laws.

I term the idea of an intelligence in which the morally most perfect

will, united with supreme blessedness, is the cause of all happiness in

the world, so far as happiness stands in strict relation to morality

(as the worthiness of being happy), the ideal of the supreme Good. It

is only, then, in the ideal of the supreme original good, that pure

reason can find the ground of the practically necessary connection of

both elements of the highest derivative good, and accordingly of an

intelligible, that is, moral world. Now since we are necessitated by

reason to conceive ourselves as belonging to such a world, while the

senses present to us nothing but a world of phenomena, we must assume

the former as a consequence of our conduct in the world of sense (since

the world of sense gives us no hint of it), and therefore as future in

relation to us. Thus God and a future life are two hypotheses which,

according to the principles of pure reason, are inseparable from the

obligation which this reason imposes upon us.

Morality per se constitutes a system. But we can form no system of

happiness, except in so far as it is dispensed in strict proportion to

morality. But this is only possible in the intelligible world, under a

wise author and ruler. Such a ruler, together with life in such a

world, which we must look upon as future, reason finds itself compelled

to assume; or it must regard the moral laws as idle dreams, since the

necessary consequence which this same reason connects with them must,

without this hypothesis, fall to the ground. Hence also the moral laws

are universally regarded as commands, which they could not be did they

not connect à priori adequate consequences with their dictates, and

thus carry with them promises and threats. But this, again, they could

not do, did they not reside in a necessary being, as the Supreme Good,

which alone can render such a teleological unity possible.

Leibnitz termed the world, when viewed in relation to the rational

beings which it contains, and the moral relations in which they stand

to each other, under the government of the Supreme Good, the kingdom of

Grace, and distinguished it from the kingdom of Nature, in which these

rational beings live, under moral laws, indeed, but expect no other

consequences from their actions than such as follow according to the

course of nature in the world of sense. To view ourselves, therefore,

as in the kingdom of grace, in which all happiness awaits us, except in

so far as we ourselves limit our participation in it by actions which

render us unworthy of happiness, is a practically necessary idea of

reason.

Practical laws, in so far as they are subjective grounds of actions,

that is, subjective principles, are termed maxims. The judgements of

moral according to in its purity and ultimate results are framed

according ideas; the observance of its laws, according to maxims.

The whole course of our life must be subject to moral maxims; but this

is impossible, unless with the moral law, which is a mere idea, reason

connects an efficient cause which ordains to all conduct which is in

conformity with the moral law an issue either in this or in another

life, which is in exact conformity with our highest aims. Thus, without

a God and without a world, invisible to us now, but hoped for, the

glorious ideas of morality are, indeed, objects of approbation and of

admiration, but cannot be the springs of purpose and action. For they

do not satisfy all the aims which are natural to every rational being,

and which are determined à priori by pure reason itself, and necessary.

Happiness alone is, in the view of reason, far from being the complete

good. Reason does not approve of it (however much inclination may

desire it), except as united with desert. On the other hand, morality

alone, and with it, mere desert, is likewise far from being the

complete good. To make it complete, he who conducts himself in a manner

not unworthy of happiness, must be able to hope for the possession of

happiness. Even reason, unbiased by private ends, or interested

considerations, cannot judge otherwise, if it puts itself in the place

of a being whose business it is to dispense all happiness to others.

For in the practical idea both points are essentially combined, though

in such a way that participation in happiness is rendered possible by

the moral disposition, as its condition, and not conversely, the moral

disposition by the prospect of happiness. For a disposition which

should require the prospect of happiness as its necessary condition

would not be moral, and hence also would not be worthy of complete

happiness—a happiness which, in the view of reason, recognizes no

limitation but such as arises from our own immoral conduct.

Happiness, therefore, in exact proportion with the morality of rational

beings (whereby they are made worthy of happiness), constitutes alone

the supreme good of a world into which we absolutely must transport

ourselves according to the commands of pure but practical reason. This

world is, it is true, only an intelligible world; for of such a

systematic unity of ends as it requires, the world of sense gives us no

hint. Its reality can be based on nothing else but the hypothesis of a

supreme original good. In it independent reason, equipped with all the

sufficiency of a supreme cause, founds, maintains, and fulfils the

universal order of things, with the most perfect teleological harmony,

however much this order may be hidden from us in the world of sense.

This moral theology has the peculiar advantage, in contrast with

speculative theology, of leading inevitably to the conception of a

sole, perfect, and rational First Cause, whereof speculative theology

does not give us any indication on objective grounds, far less any

convincing evidence. For we find neither in transcendental nor in

natural theology, however far reason may lead us in these, any ground

to warrant us in assuming the existence of one only Being, which stands

at the head of all natural causes, and on which these are entirely

dependent. On the other hand, if we take our stand on moral unity as a

necessary law of the universe, and from this point of view consider

what is necessary to give this law adequate efficiency and, for us,

obligatory force, we must come to the conclusion that there is one only

supreme will, which comprehends all these laws in itself. For how,

under different wills, should we find complete unity of ends? This will

must be omnipotent, that all nature and its relation to morality in the

world may be subject to it; omniscient, that it may have knowledge of

the most secret feelings and their moral worth; omnipresent, that it

may be at hand to supply every necessity to which the highest weal of

the world may give rise; eternal, that this harmony of nature and

liberty may never fail; and so on.

But this systematic unity of ends in this world of intelligences—which,

as mere nature, is only a world of sense, but, as a system of freedom

of volition, may be termed an intelligible, that is, moral world

(regnum gratiae)—leads inevitably also to the teleological unity of all

things which constitute this great whole, according to universal

natural laws—just as the unity of the former is according to universal

and necessary moral laws—and unites the practical with the speculative

reason. The world must be represented as having originated from an

idea, if it is to harmonize with that use of reason without which we

cannot even consider ourselves as worthy of reason—namely, the moral

use, which rests entirely on the idea of the supreme good. Hence the

investigation of nature receives a teleological direction, and becomes,

in its widest extension, physico-theology. But this, taking its rise in

moral order as a unity founded on the essence of freedom, and not

accidentally instituted by external commands, establishes the

teleological view of nature on grounds which must be inseparably

connected with the internal possibility of things. This gives rise to a

transcendental theology, which takes the ideal of the highest

ontological perfection as a principle of systematic unity; and this

principle connects all things according to universal and necessary

natural laws, because all things have their origin in the absolute

necessity of the one only Primal Being.

What use can we make of our understanding, even in respect of

experience, if we do not propose ends to ourselves? But the highest

ends are those of morality, and it is only pure reason that can give us

the knowledge of these. Though supplied with these, and putting

ourselves under their guidance, we can make no teleological use of the

knowledge of nature, as regards cognition, unless nature itself has

established teleological unity. For without this unity we should not

even possess reason, because we should have no school for reason, and

no cultivation through objects which afford the materials for its

conceptions. But teleological unity is a necessary unity, and founded

on the essence of the individual will itself. Hence this will, which is

the condition of the application of this unity in concreto, must be so

likewise. In this way the transcendental enlargement of our rational

cognition would be, not the cause, but merely the effect of the

practical teleology which pure reason imposes upon us.

Hence, also, we find in the history of human reason that, before the

moral conceptions were sufficiently purified and determined, and before

men had attained to a perception of the systematic unity of ends

according to these conceptions and from necessary principles, the

knowledge of nature, and even a considerable amount of intellectual

culture in many other sciences, could produce only rude and vague

conceptions of the Deity, sometimes even admitting of an astonishing

indifference with regard to this question altogether. But the more

enlarged treatment of moral ideas, which was rendered necessary by the

extreme pure moral law of our religion, awakened the interest, and

thereby quickened the perceptions of reason in relation to this object.

In this way, and without the help either of an extended acquaintance

with nature, or of a reliable transcendental insight (for these have

been wanting in all ages), a conception of the Divine Being was arrived

at, which we now hold to be the correct one, not because speculative

reason convinces us of its correctness, but because it accords with the

moral principles of reason. Thus it is to pure reason, but only in its

practical use, that we must ascribe the merit of having connected with

our highest interest a cognition, of which mere speculation was able

only to form a conjecture, but the validity of which it was unable to

establish—and of having thereby rendered it, not indeed a demonstrated

dogma, but a hypothesis absolutely necessary to the essential ends of

reason.

But if practical reason has reached this elevation, and has attained to

the conception of a sole Primal Being as the supreme good, it must not,

therefore, imagine that it has transcended the empirical conditions of

its application, and risen to the immediate cognition of new objects;

it must not presume to start from the conception which it has gained,

and to deduce from it the moral laws themselves. For it was these very

laws, the internal practical necessity of which led us to the

hypothesis of an independent cause, or of a wise ruler of the universe,

who should give them effect. Hence we are not entitled to regard them

as accidental and derived from the mere will of the ruler, especially

as we have no conception of such a will, except as formed in accordance

with these laws. So far, then, as practical reason has the right to

conduct us, we shall not look upon actions as binding on us, because

they are the commands of God, but we shall regard them as divine

commands, because we are internally bound by them. We shall study

freedom under the teleological unity which accords with principles of

reason; we shall look upon ourselves as acting in conformity with the

divine will only in so far as we hold sacred the moral law which reason

teaches us from the nature of actions themselves, and we shall believe

that we can obey that will only by promoting the weal of the universe

in ourselves and in others. Moral theology is, therefore, only of

immanent use. It teaches us to fulfil our destiny here in the world, by

placing ourselves in harmony with the general system of ends, and warns

us against the fanaticism, nay, the crime of depriving reason of its

legislative authority in the moral conduct of life, for the purpose of

directly connecting this authority with the idea of the Supreme Being.

For this would be, not an immanent, but a transcendent use of moral

theology, and, like the transcendent use of mere speculation, would

inevitably pervert and frustrate the ultimate ends of reason.

Section III. Of Opinion, Knowledge, and Belief

The holding of a thing to be true is a phenomenon in our understanding

which may rest on objective grounds, but requires, also, subjective

causes in the mind of the person judging. If a judgement is valid for

every rational being, then its ground is objectively sufficient, and it

is termed a conviction. If, on the other hand, it has its ground in the

particular character of the subject, it is termed a persuasion.

Persuasion is a mere illusion, the ground of the judgement, which lies

solely in the subject, being regarded as objective. Hence a judgement

of this kind has only private validity—is only valid for the individual

who judges, and the holding of a thing to be true in this way cannot be

communicated. But truth depends upon agreement with the object, and

consequently the judgements of all understandings, if true, must be in

agreement with each other (consentientia uni tertio consentiunt inter

se). Conviction may, therefore, be distinguished, from an external

point of view, from persuasion, by the possibility of communicating it

and by showing its validity for the reason of every man; for in this

case the presumption, at least, arises that the agreement of all

judgements with each other, in spite of the different characters of

individuals, rests upon the common ground of the agreement of each with

the object, and thus the correctness of the judgement is established.

Persuasion, accordingly, cannot be subjectively distinguished from

conviction, that is, so long as the subject views its judgement simply

as a phenomenon of its own mind. But if we inquire whether the grounds

of our judgement, which are valid for us, produce the same effect on

the reason of others as on our own, we have then the means, though only

subjective means, not, indeed, of producing conviction, but of

detecting the merely private validity of the judgement; in other words,

of discovering that there is in it the element of mere persuasion.

If we can, in addition to this, develop the subjective causes of the

judgement, which we have taken for its objective grounds, and thus

explain the deceptive judgement as a phenomenon in our mind, apart

altogether from the objective character of the object, we can then

expose the illusion and need be no longer deceived by it, although, if

its subjective cause lies in our nature, we cannot hope altogether to

escape its influence.

I can only maintain, that is, affirm as necessarily valid for every

one, that which produces conviction. Persuasion I may keep for myself,

if it is agreeable to me; but I cannot, and ought not, to attempt to

impose it as binding upon others.

Holding for true, or the subjective validity of a judgement in relation

to conviction (which is, at the same time, objectively valid), has the

three following degrees: opinion, belief, and knowledge. Opinion is a

consciously insufficient judgement, subjectively as well as

objectively. Belief is subjectively sufficient, but is recognized as

being objectively insufficient. Knowledge is both subjectively and

objectively sufficient. Subjective sufficiency is termed conviction

(for myself); objective sufficiency is termed certainty (for all). I

need not dwell longer on the explanation of such simple conceptions.

I must never venture to be of opinion, without knowing something, at

least, by which my judgement, in itself merely problematical, is

brought into connection with the truth—which connection, although not

perfect, is still something more than an arbitrary fiction. Moreover,

the law of such a connection must be certain. For if, in relation to

this law, I have nothing more than opinion, my judgement is but a play

of the imagination, without the least relation to truth. In the

judgements of pure reason, opinion has no place. For, as they do not

rest on empirical grounds and as the sphere of pure reason is that of

necessary truth and à priori cognition, the principle of connection in

it requires universality and necessity, and consequently perfect

certainty—otherwise we should have no guide to the truth at all. Hence

it is absurd to have an opinion in pure mathematics; we must know, or

abstain from forming a judgement altogether. The case is the same with

the maxims of morality. For we must not hazard an action on the mere

opinion that it is allowed, but we must know it to be so. In the

transcendental sphere of reason, on the other hand, the term opinion is

too weak, while the word knowledge is too strong. From the merely

speculative point of view, therefore, we cannot form a judgement at

all. For the subjective grounds of a judgement, such as produce belief,

cannot be admitted in speculative inquiries, inasmuch as they cannot

stand without empirical support and are incapable of being communicated

to others in equal measure.

But it is only from the practical point of view that a theoretically

insufficient judgement can be termed belief. Now the practical

reference is either to skill or to morality; to the former, when the

end proposed is arbitrary and accidental, to the latter, when it is

absolutely necessary.

If we propose to ourselves any end whatever, the conditions of its

attainment are hypothetically necessary. The necessity is subjectively,

but still only comparatively, sufficient, if I am acquainted with no

other conditions under which the end can be attained. On the other

hand, it is sufficient, absolutely and for every one, if I know for

certain that no one can be acquainted with any other conditions under

which the attainment of the proposed end would be possible. In the

former case my supposition—my judgement with regard to certain

conditions—is a merely accidental belief; in the latter it is a

necessary belief. The physician must pursue some course in the case of

a patient who is in danger, but is ignorant of the nature of the

disease. He observes the symptoms, and concludes, according to the best

of his judgement, that it is a case of phthisis. His belief is, even in

his own judgement, only contingent: another man might, perhaps come

nearer the truth. Such a belief, contingent indeed, but still forming

the ground of the actual use of means for the attainment of certain

ends, I term Pragmatical belief.

The usual test, whether that which any one maintains is merely his

persuasion, or his subjective conviction at least, that is, his firm

belief, is a bet. It frequently happens that a man delivers his

opinions with so much boldness and assurance, that he appears to be

under no apprehension as to the possibility of his being in error. The

offer of a bet startles him, and makes him pause. Sometimes it turns

out that his persuasion may be valued at a ducat, but not at ten. For

he does not hesitate, perhaps, to venture a ducat, but if it is

proposed to stake ten, he immediately becomes aware of the possibility

of his being mistaken—a possibility which has hitherto escaped his

observation. If we imagine to ourselves that we have to stake the

happiness of our whole life on the truth of any proposition, our

judgement drops its air of triumph, we take the alarm, and discover the

actual strength of our belief. Thus pragmatical belief has degrees,

varying in proportion to the interests at stake.

Now, in cases where we cannot enter upon any course of action in

reference to some object, and where, accordingly, our judgement is

purely theoretical, we can still represent to ourselves, in thought,

the possibility of a course of action, for which we suppose that we

have sufficient grounds, if any means existed of ascertaining the truth

of the matter. Thus we find in purely theoretical judgements an

analogon of practical judgements, to which the word belief may properly

be applied, and which we may term doctrinal belief. I should not

hesitate to stake my all on the truth of the proposition—if there were

any possibility of bringing it to the test of experience—that, at

least, some one of the planets, which we see, is inhabited. Hence I say

that I have not merely the opinion, but the strong belief, on the

correctness of which I would stake even many of the advantages of life,

that there are inhabitants in other worlds.

Now we must admit that the doctrine of the existence of God belongs to

doctrinal belief. For, although in respect to the theoretical cognition

of the universe I do not require to form any theory which necessarily

involves this idea, as the condition of my explanation of the phenomena

which the universe presents, but, on the contrary, am rather bound so

to use my reason as if everything were mere nature, still teleological

unity is so important a condition of the application of my reason to

nature, that it is impossible for me to ignore it—especially since, in

addition to these considerations, abundant examples of it are supplied

by experience. But the sole condition, so far as my knowledge extends,

under which this unity can be my guide in the investigation of nature,

is the assumption that a supreme intelligence has ordered all things

according to the wisest ends. Consequently, the hypothesis of a wise

author of the universe is necessary for my guidance in the

investigation of nature—is the condition under which alone I can fulfil

an end which is contingent indeed, but by no means unimportant.

Moreover, since the result of my attempts so frequently confirms the

utility of this assumption, and since nothing decisive can be adduced

against it, it follows that it would be saying far too little to term

my judgement, in this case, a mere opinion, and that, even in this

theoretical connection, I may assert that I firmly believe in God.

Still, if we use words strictly, this must not be called a practical,

but a doctrinal belief, which the theology of nature (physico-theology)

must also produce in my mind. In the wisdom of a Supreme Being, and in

the shortness of life, so inadequate to the development of the glorious

powers of human nature, we may find equally sufficient grounds for a

doctrinal belief in the future life of the human soul.

The expression of belief is, in such cases, an expression of modesty

from the objective point of view, but, at the same time, of firm

confidence, from the subjective. If I should venture to term this

merely theoretical judgement even so much as a hypothesis which I am

entitled to assume; a more complete conception, with regard to another

world and to the cause of the world, might then be justly required of

me than I am, in reality, able to give. For, if I assume anything, even

as a mere hypothesis, I must, at least, know so much of the properties

of such a being as will enable me, not to form the conception, but to

imagine the existence of it. But the word belief refers only to the

guidance which an idea gives me, and to its subjective influence on the

conduct of my reason, which forces me to hold it fast, though I may not

be in a position to give a speculative account of it.

But mere doctrinal belief is, to some extent, wanting in stability. We

often quit our hold of it, in consequence of the difficulties which

occur in speculation, though in the end we inevitably return to it

again.

It is quite otherwise with moral belief. For in this sphere action is

absolutely necessary, that is, I must act in obedience to the moral law

in all points. The end is here incontrovertibly established, and there

is only one condition possible, according to the best of my perception,

under which this end can harmonize with all other ends, and so have

practical validity—namely, the existence of a God and of a future

world. I know also, to a certainty, that no one can be acquainted with

any other conditions which conduct to the same unity of ends under the

moral law. But since the moral precept is, at the same time, my maxim

(as reason requires that it should be), I am irresistibly constrained

to believe in the existence of God and in a future life; and I am sure

that nothing can make me waver in this belief, since I should thereby

overthrow my moral maxims, the renunciation of which would render me

hateful in my own eyes.

Thus, while all the ambitious attempts of reason to penetrate beyond

the limits of experience end in disappointment, there is still enough

left to satisfy us in a practical point of view. No one, it is true,

will be able to boast that he knows that there is a God and a future

life; for, if he knows this, he is just the man whom I have long wished

to find. All knowledge, regarding an object of mere reason, can be

communicated; and I should thus be enabled to hope that my own

knowledge would receive this wonderful extension, through the

instrumentality of his instruction. No, my conviction is not logical,

but moral certainty; and since it rests on subjective grounds (of the

moral sentiment), I must not even say: It is morally certain that there

is a God, etc., but: I am morally certain, that is, my belief in God

and in another world is so interwoven with my moral nature that I am

under as little apprehension of having the former torn from me as of

losing the latter.

The only point in this argument that may appear open to suspicion is

that this rational belief presupposes the existence of moral

sentiments. If we give up this assumption, and take a man who is

entirely indifferent with regard to moral laws, the question which

reason proposes, becomes then merely a problem for speculation and may,

indeed, be supported by strong grounds from analogy, but not by such as

will compel the most obstinate scepticism to give way.[79] But in these

questions no man is free from all interest. For though the want of good

sentiments may place him beyond the influence of moral interests, still

even in this case enough may be left to make him fear the existence of

God and a future life. For he cannot pretend to any certainty of the

non-existence of God and of a future life, unless—since it could only

be proved by mere reason, and therefore apodeictically—he is prepared

to establish the impossibility of both, which certainly no reasonable

man would undertake to do. This would be a negative belief, which could

not, indeed, produce morality and good sentiments, but still could

produce an analogon of these, by operating as a powerful restraint on

the outbreak of evil dispositions.

[79] The human mind (as, I believe, every rational being must of

necessity do) takes a natural interest in morality, although this

interest is not undivided, and may not be practically in

preponderance. If you strengthen and increase it, you will find the

reason become docile, more enlightened, and more capable of uniting

the speculative interest with the practical. But if you do not take

care at the outset, or at least midway, to make men good, you will

never force them into an honest belief.

But, it will be said, is this all that pure reason can effect, in

opening up prospects beyond the limits of experience? Nothing more than

two articles of belief? Common sense could have done as much as this,

without taking the philosophers to counsel in the matter!

I shall not here eulogize philosophy for the benefits which the

laborious efforts of its criticism have conferred on human reason—even

granting that its merit should turn out in the end to be only

negative—for on this point something more will be said in the next

section. But, I ask, do you require that that knowledge which concerns

all men, should transcend the common understanding, and should only be

revealed to you by philosophers? The very circumstance which has called

forth your censure, is the best confirmation of the correctness of our

previous assertions, since it discloses, what could not have been

foreseen, that Nature is not chargeable with any partial distribution

of her gifts in those matters which concern all men without distinction

and that, in respect to the essential ends of human nature, we cannot

advance further with the help of the highest philosophy, than under the

guidance which nature has vouchsafed to the meanest understanding.

Chapter III. The Architectonic of Pure Reason

By the term architectonic I mean the art of constructing a system.

Without systematic unity, our knowledge cannot become science; it will

be an aggregate, and not a system. Thus architectonic is the doctrine

of the scientific in cognition, and therefore necessarily forms part of

our methodology.

Reason cannot permit our knowledge to remain in an unconnected and

rhapsodistic state, but requires that the sum of our cognitions should

constitute a system. It is thus alone that they can advance the ends of

reason. By a system I mean the unity of various cognitions under one

idea. This idea is the conception—given by reason—of the form of a

whole, in so far as the conception determines à priori not only the

limits of its content, but the place which each of its parts is to

occupy. The scientific idea contains, therefore, the end and the form

of the whole which is in accordance with that end. The unity of the

end, to which all the parts of the system relate, and through which all

have a relation to each other, communicates unity to the whole system,

so that the absence of any part can be immediately detected from our

knowledge of the rest; and it determines à priori the limits of the

system, thus excluding all contingent or arbitrary additions. The whole

is thus an organism (articulatio), and not an aggregate (coacervatio);

it may grow from within (per intussusceptionem), but it cannot increase

by external additions (per appositionem). It is, thus, like an animal

body, the growth of which does not add any limb, but, without changing

their proportions, makes each in its sphere stronger and more active.

We require, for the execution of the idea of a system, a schema, that

is, a content and an arrangement of parts determined à priori by the

principle which the aim of the system prescribes. A schema which is not

projected in accordance with an idea, that is, from the standpoint of

the highest aim of reason, but merely empirically, in accordance with

accidental aims and purposes (the number of which cannot be

predetermined), can give us nothing more than technical unity. But the

schema which is originated from an idea (in which case reason presents

us with aims à priori, and does not look for them to experience), forms

the basis of architectonical unity. A science, in the proper

acceptation of that term, cannot be formed technically, that is, from

observation of the similarity existing between different objects, and

the purely contingent use we make of our knowledge in concreto with

reference to all kinds of arbitrary external aims; its constitution

must be framed on architectonical principles, that is, its parts must

be shown to possess an essential affinity, and be capable of being

deduced from one supreme and internal aim or end, which forms the

condition of the possibility of the scientific whole. The schema of a

science must give à priori the plan of it (monogramma), and the

division of the whole into parts, in conformity with the idea of the

science; and it must also distinguish this whole from all others,

according to certain understood principles.

No one will attempt to construct a science, unless he have some idea to

rest on as a proper basis. But, in the elaboration of the science, he

finds that the schema, nay, even the definition which he at first gave

of the science, rarely corresponds with his idea; for this idea lies,

like a germ, in our reason, its parts undeveloped and hid even from

microscopical observation. For this reason, we ought to explain and

define sciences, not according to the description which the originator

gives of them, but according to the idea which we find based in reason

itself, and which is suggested by the natural unity of the parts of

the science already accumulated. For it will often be found that the

originator of a science and even his latest successors remain attached

to an erroneous idea, which they cannot render clear to themselves, and

that they thus fail in determining the true content, the articulation

or systematic unity, and the limits of their science.

It is unfortunate that, only after having occupied ourselves for a long

time in the collection of materials, under the guidance of an idea

which lies undeveloped in the mind, but not according to any definite

plan of arrangement—nay, only after we have spent much time and labour

in the technical disposition of our materials, does it become possible

to view the idea of a science in a clear light, and to project,

according to architectonical principles, a plan of the whole, in

accordance with the aims of reason. Systems seem, like certain worms,

to be formed by a kind of generatio aequivoca—by the mere confluence of

conceptions, and to gain completeness only with the progress of time.

But the schema or germ of all lies in reason; and thus is not only

every system organized according to its own idea, but all are united

into one grand system of human knowledge, of which they form members.

For this reason, it is possible to frame an architectonic of all human

cognition, the formation of which, at the present time, considering the

immense materials collected or to be found in the ruins of old systems,

would not indeed be very difficult. Our purpose at present is merely to

sketch the plan of the architectonic of all cognition given by pure

reason; and we begin from the point where the main root of human

knowledge divides into two, one of which is reason. By reason I

understand here the whole higher faculty of cognition, the rational

being placed in contradistinction to the empirical.

If I make complete abstraction of the content of cognition, objectively

considered, all cognition is, from a subjective point of view, either

historical or rational. Historical cognition is cognitio ex datis,

rational, cognitio ex principiis. Whatever may be the original source

of a cognition, it is, in relation to the person who possesses it,

merely historical, if he knows only what has been given him from

another quarter, whether that knowledge was communicated by direct

experience or by instruction. Thus the person who has learned a system

of philosophy—say the Wolfian—although he has a perfect knowledge of

all the principles, definitions, and arguments in that philosophy, as

well as of the divisions that have been made of the system, possesses

really no more than an historical knowledge of the Wolfian system; he

knows only what has been told him, his judgements are only those which

he has received from his teachers. Dispute the validity of a

definition, and he is completely at a loss to find another. He has

formed his mind on another’s; but the imitative faculty is not the

productive. His knowledge has not been drawn from reason; and although,

objectively considered, it is rational knowledge, subjectively, it is

merely historical. He has learned this or that philosophy and is merely

a plaster cast of a living man. Rational cognitions which are

objective, that is, which have their source in reason, can be so termed

from a subjective point of view, only when they have been drawn by the

individual himself from the sources of reason, that is, from

principles; and it is in this way alone that criticism, or even the

rejection of what has been already learned, can spring up in the mind.

All rational cognition is, again, based either on conceptions, or on

the construction of conceptions. The former is termed philosophical,

the latter mathematical. I have already shown the essential difference

of these two methods of cognition in the first chapter. A cognition may

be objectively philosophical and subjectively historical—as is the case

with the majority of scholars and those who cannot look beyond the

limits of their system, and who remain in a state of pupilage all their

lives. But it is remarkable that mathematical knowledge, when committed

to memory, is valid, from the subjective point of view, as rational

knowledge also, and that the same distinction cannot be drawn here as

in the case of philosophical cognition. The reason is that the only way

of arriving at this knowledge is through the essential principles of

reason, and thus it is always certain and indisputable; because reason

is employed in concreto—but at the same time à priori—that is, in pure

and, therefore, infallible intuition; and thus all causes of illusion

and error are excluded. Of all the à priori sciences of reason,

therefore, mathematics alone can be learned. Philosophy—unless it be in

an historical manner—cannot be learned; we can at most learn to

philosophize.

Philosophy is the system of all philosophical cognition. We must use

this term in an objective sense, if we understand by it the archetype

of all attempts at philosophizing, and the standard by which all

subjective philosophies are to be judged. In this sense, philosophy is

merely the idea of a possible science, which does not exist in

concreto, but to which we endeavour in various ways to approximate,

until we have discovered the right path to pursue—a path overgrown by

the errors and illusions of sense—and the image we have hitherto tried

in vain to shape has become a perfect copy of the great prototype.

Until that time, we cannot learn philosophy—it does not exist; if it

does, where is it, who possesses it, and how shall we know it? We can

only learn to philosophize; in other words, we can only exercise our

powers of reasoning in accordance with general principles, retaining at

the same time, the right of investigating the sources of these

principles, of testing, and even of rejecting them.

Until then, our conception of philosophy is only a scholastic

conception—a conception, that is, of a system of cognition which we are

trying to elaborate into a science; all that we at present know being

the systematic unity of this cognition, and consequently the logical

completeness of the cognition for the desired end. But there is also a

cosmical conception (conceptus cosmicus) of philosophy, which has

always formed the true basis of this term, especially when philosophy

was personified and presented to us in the ideal of a philosopher. In

this view philosophy is the science of the relation of all cognition to

the ultimate and essential aims of human reason (teleologia rationis

humanae), and the philosopher is not merely an artist—who occupies

himself with conceptions—but a lawgiver, legislating for human reason.

In this sense of the word, it would be in the highest degree arrogant

to assume the title of philosopher, and to pretend that we had reached

the perfection of the prototype which lies in the idea alone.

The mathematician, the natural philosopher, and the logician—how far

soever the first may have advanced in rational, and the two latter in

philosophical knowledge—are merely artists, engaged in the arrangement

and formation of conceptions; they cannot be termed philosophers. Above

them all, there is the ideal teacher, who employs them as instruments

for the advancement of the essential aims of human reason. Him alone

can we call philosopher; but he nowhere exists. But the idea of his

legislative power resides in the mind of every man, and it alone

teaches us what kind of systematic unity philosophy demands in view of

the ultimate aims of reason. This idea is, therefore, a cosmical

conception.[80]

[80] By a cosmical conception, I mean one in which all men necessarily

take an interest; the aim of a science must accordingly be determined

according to scholastic conceptions, if it is regarded merely as a

means to certain arbitrarily proposed ends.

In view of the complete systematic unity of reason, there can only be

one ultimate end of all the operations of the mind. To this all other

aims are subordinate, and nothing more than means for its attainment.

This ultimate end is the destination of man, and the philosophy which

relates to it is termed moral philosophy. The superior position

occupied by moral philosophy, above all other spheres for the

operations of reason, sufficiently indicates the reason why the

ancients always included the idea—and in an especial manner—of moralist

in that of philosopher. Even at the present day, we call a man who

appears to have the power of self-government, even although his

knowledge may be very limited, by the name of philosopher.

The legislation of human reason, or philosophy, has two objects—nature

and freedom—and thus contains not only the laws of nature, but also

those of ethics, at first in two separate systems, which, finally,

merge into one grand philosophical system of cognition. The philosophy

of nature relates to that which is, that of ethics to that which ought

to be.

But all philosophy is either cognition on the basis of pure reason, or

the cognition of reason on the basis of empirical principles. The

former is termed pure, the latter empirical philosophy.

The philosophy of pure reason is either propædeutic, that is, an

inquiry into the powers of reason in regard to pure à priori cognition,

and is termed critical philosophy; or it is, secondly, the system of

pure reason—a science containing the systematic presentation of the

whole body of philosophical knowledge, true as well as illusory, given

by pure reason—and is called metaphysic. This name may, however, be

also given to the whole system of pure philosophy, critical philosophy

included, and may designate the investigation into the sources or

possibility of à priori cognition, as well as the presentation of the à

priori cognitions which form a system of pure philosophy—excluding, at

the same time, all empirical and mathematical elements.

Metaphysic is divided into that of the speculative and that of the

practical use of pure reason, and is, accordingly, either the

metaphysic of nature, or the metaphysic of ethics. The former contains

all the pure rational principles—based upon conceptions alone (and thus

excluding mathematics)—of all theoretical cognition; the latter, the

principles which determine and necessitate à priori all action. Now

moral philosophy alone contains a code of laws—for the regulation of

our actions—which are deduced from principles entirely à priori. Hence

the metaphysic of ethics is the only pure moral philosophy, as it is

not based upon anthropological or other empirical considerations. The

metaphysic of speculative reason is what is commonly called metaphysic

in the more limited sense. But as pure moral philosophy properly forms

a part of this system of cognition, we must allow it to retain the name

of metaphysic, although it is not requisite that we should insist on so

terming it in our present discussion.

It is of the highest importance to separate those cognitions which

differ from others both in kind and in origin, and to take great care

that they are not confounded with those with which they are generally

found connected. What the chemist does in the analysis of substances,

what the mathematician in pure mathematics, is, in a still higher

degree, the duty of the philosopher, that the value of each different

kind of cognition, and the part it takes in the operations of the mind,

may be clearly defined. Human reason has never wanted a metaphysic of

some kind, since it attained the power of thought, or rather of

reflection; but it has never been able to keep this sphere of thought

and cognition pure from all admixture of foreign elements. The idea of

a science of this kind is as old as speculation itself; and what mind

does not speculate—either in the scholastic or in the popular fashion?

At the same time, it must be admitted that even thinkers by profession

have been unable clearly to explain the distinction between the two

elements of our cognition—the one completely à priori, the other à

posteriori; and hence the proper definition of a peculiar kind of

cognition, and with it the just idea of a science which has so long and

so deeply engaged the attention of the human mind, has never been

established. When it was said: “Metaphysic is the science of the first

principles of human cognition,” this definition did not signalize a

peculiarity in kind, but only a difference in degree; these first

principles were thus declared to be more general than others, but no

criterion of distinction from empirical principles was given. Of these

some are more general, and therefore higher, than others; and—as we

cannot distinguish what is completely à priori from that which is known

to be à posteriori—where shall we draw the line which is to separate

the higher and so-called first principles, from the lower and

subordinate principles of cognition? What would be said if we were

asked to be satisfied with a division of the epochs of the world into

the earlier centuries and those following them? “Does the fifth, or the

tenth century belong to the earlier centuries?” it would be asked. In

the same way I ask: Does the conception of extension belong to

metaphysics? You answer, “Yes.” Well, that of body too? “Yes.” And that

of a fluid body? You stop, you are unprepared to admit this; for if you

do, everything will belong to metaphysics. From this it is evident that

the mere degree of subordination—of the particular to the

general—cannot determine the limits of a science; and that, in the

present case, we must expect to find a difference in the conceptions of

metaphysics both in kind and in origin. The fundamental idea of

metaphysics was obscured on another side by the fact that this kind of

à priori cognition showed a certain similarity in character with the

science of mathematics. Both have the property in common of possessing

an à priori origin; but, in the one, our knowledge is based upon

conceptions, in the other, on the construction of conceptions. Thus a

decided dissimilarity between philosophical and mathematical cognition

comes out—a dissimilarity which was always felt, but which could not be

made distinct for want of an insight into the criteria of the

difference. And thus it happened that, as philosophers themselves

failed in the proper development of the idea of their science, the

elaboration of the science could not proceed with a definite aim, or

under trustworthy guidance. Thus, too, philosophers, ignorant of the

path they ought to pursue and always disputing with each other

regarding the discoveries which each asserted he had made, brought

their science into disrepute with the rest of the world, and finally,

even among themselves.

All pure à priori cognition forms, therefore, in view of the peculiar

faculty which originates it, a peculiar and distinct unity; and

metaphysic is the term applied to the philosophy which attempts to

represent that cognition in this systematic unity. The speculative part

of metaphysic, which has especially appropriated this appellation—that

which we have called the metaphysic of nature—and which considers

everything, as it is (not as it ought to be), by means of à priori

conceptions, is divided in the following manner.

Metaphysic, in the more limited acceptation of the term, consists of

two parts—transcendental philosophy and the physiology of pure reason.

The former presents the system of all the conceptions and principles

belonging to the understanding and the reason, and which relate to

objects in general, but not to any particular given objects

(Ontologia); the latter has nature for its subject-matter, that is, the

sum of given objects—whether given to the senses, or, if we will, to

some other kind of intuition—and is accordingly physiology, although

only rationalis. But the use of the faculty of reason in this rational

mode of regarding nature is either physical or hyperphysical, or, more

properly speaking, immanent or transcendent. The former relates to

nature, in so far as our knowledge regarding it may be applied in

experience (in concreto); the latter to that connection of the objects

of experience, which transcends all experience. Transcendent physiology

has, again, an internal and an external connection with its object,

both, however, transcending possible experience; the former is the

physiology of nature as a whole, or transcendental cognition of the

world, the latter of the connection of the whole of nature with a being

above nature, or transcendental cognition of God.

Immanent physiology, on the contrary, considers nature as the sum of

all sensuous objects, consequently, as it is presented to us—but still

according to à priori conditions, for it is under these alone that

nature can be presented to our minds at all. The objects of immanent

physiology are of two kinds: 1. Those of the external senses, or

corporeal nature; 2. The object of the internal sense, the soul, or, in

accordance with our fundamental conceptions of it, thinking nature. The

metaphysics of corporeal nature is called physics; but, as it must

contain only the principles of an à priori cognition of nature, we must

term it rational physics. The metaphysics of thinking nature is called

psychology, and for the same reason is to be regarded as merely the

rational cognition of the soul.

Thus the whole system of metaphysics consists of four principal parts:

1. Ontology; 2. Rational Physiology; 3. Rational cosmology; and 4.

Rational theology. The second part—that of the rational doctrine of

nature—may be subdivided into two, physica rationalis[81] and

psychologia rationalis.

[81] It must not be supposed that I mean by this appellation what is

generally called physica general is, and which is rather mathematics

than a philosophy of nature. For the metaphysic of nature is

completely different from mathematics, nor is it so rich in results,

although it is of great importance as a critical test of the

application of pure understanding—cognition to nature. For want of its

guidance, even mathematicians, adopting certain common notions—which

are, in fact, metaphysical—have unconsciously crowded their theories

of nature with hypotheses, the fallacy of which becomes evident upon

the application of the principles of this metaphysic, without

detriment, however, to the employment of mathematics in this sphere of

cognition.

The fundamental idea of a philosophy of pure reason of necessity

dictates this division; it is, therefore, architectonical—in accordance

with the highest aims of reason, and not merely technical, or according

to certain accidentally-observed similarities existing between the

different parts of the whole science. For this reason, also, is the

division immutable and of legislative authority. But the reader may

observe in it a few points to which he ought to demur, and which may

weaken his conviction of its truth and legitimacy.

In the first place, how can I desire an à priori cognition or

metaphysic of objects, in so far as they are given à posteriori? and

how is it possible to cognize the nature of things according to à

priori principles, and to attain to a rational physiology? The answer

is this. We take from experience nothing more than is requisite to

present us with an object (in general) of the external or of the

internal sense; in the former case, by the mere conception of matter

(impenetrable and inanimate extension), in the latter, by the

conception of a thinking being—given in the internal empirical

representation, I think. As to the rest, we must not employ in our

metaphysic of these objects any empirical principles (which add to the

content of our conceptions by means of experience), for the purpose of

forming by their help any judgements respecting these objects.

Secondly, what place shall we assign to empirical psychology, which has

always been considered a part of metaphysics, and from which in our

time such important philosophical results have been expected, after the

hope of constructing an à priori system of knowledge had been

abandoned? I answer: It must be placed by the side of empirical physics

or physics proper; that is, must be regarded as forming a part of

applied philosophy, the à priori principles of which are contained in

pure philosophy, which is therefore connected, although it must not be

confounded, with psychology. Empirical psychology must therefore be

banished from the sphere of metaphysics, and is indeed excluded by the

very idea of that science. In conformity, however, with scholastic

usage, we must permit it to occupy a place in metaphysics—but only as

an appendix to it. We adopt this course from motives of economy; as

psychology is not as yet full enough to occupy our attention as an

independent study, while it is, at the same time, of too great

importance to be entirely excluded or placed where it has still less

affinity than it has with the subject of metaphysics. It is a stranger

who has been long a guest; and we make it welcome to stay, until it can

take up a more suitable abode in a complete system of anthropology—the

pendant to empirical physics.

The above is the general idea of metaphysics, which, as more was

expected from it than could be looked for with justice, and as these

pleasant expectations were unfortunately never realized, fell into

general disrepute. Our Critique must have fully convinced the reader

that, although metaphysics cannot form the foundation of religion, it

must always be one of its most important bulwarks, and that human

reason, which naturally pursues a dialectical course, cannot do without

this science, which checks its tendencies towards dialectic and, by

elevating reason to a scientific and clear self-knowledge, prevents the

ravages which a lawless speculative reason would infallibly commit in

the sphere of morals as well as in that of religion. We may be sure,

therefore, whatever contempt may be thrown upon metaphysics by those

who judge a science not by its own nature, but according to the

accidental effects it may have produced, that it can never be

completely abandoned, that we must always return to it as to a beloved

one who has been for a time estranged, because the questions with which

it is engaged relate to the highest aims of humanity, and reason must

always labour either to attain to settled views in regard to these, or

to destroy those which others have already established.

Metaphysic, therefore—that of nature, as well as that of ethics, but in

an especial manner the criticism which forms the propædeutic to all

the operations of reason—forms properly that department of knowledge

which may be termed, in the truest sense of the word, philosophy. The

path which it pursues is that of science, which, when it has once been

discovered, is never lost, and never misleads. Mathematics, natural

science, the common experience of men, have a high value as means, for

the most part, to accidental ends—but at last also, to those which are

necessary and essential to the existence of humanity. But to guide them

to this high goal, they require the aid of rational cognition on the

basis of pure conceptions, which, be it termed as it may, is properly

nothing but metaphysics.

For the same reason, metaphysics forms likewise the completion of the

culture of human reason. In this respect, it is indispensable, setting

aside altogether the influence which it exerts as a science. For its

subject-matter is the elements and highest maxims of reason, which form

the basis of the possibility of some sciences and of the use of all.

That, as a purely speculative science, it is more useful in preventing

error than in the extension of knowledge, does not detract from its

value; on the contrary, the supreme office of censor which it occupies

assures to it the highest authority and importance. This office it

administers for the purpose of securing order, harmony, and well-being

to science, and of directing its noble and fruitful labours to the

highest possible aim—the happiness of all mankind.

Chapter IV. The History of Pure Reason

This title is placed here merely for the purpose of designating a

division of the system of pure reason of which I do not intend to treat

at present. I shall content myself with casting a cursory glance, from

a purely transcendental point of view—that of the nature of pure

reason—on the labours of philosophers up to the present time. They have

aimed at erecting an edifice of philosophy; but to my eye this edifice

appears to be in a very ruinous condition.

It is very remarkable, although naturally it could not have been

otherwise, that, in the infancy of philosophy, the study of the nature

of God and the constitution of a future world formed the commencement,

rather than the conclusion, as we should have it, of the speculative

efforts of the human mind. However rude the religious conceptions

generated by the remains of the old manners and customs of a less

cultivated time, the intelligent classes were not thereby prevented

from devoting themselves to free inquiry into the existence and nature

of God; and they easily saw that there could be no surer way of

pleasing the invisible ruler of the world, and of attaining to

happiness in another world at least, than a good and honest course of

life in this. Thus theology and morals formed the two chief motives, or

rather the points of attraction in all abstract inquiries. But it was

the former that especially occupied the attention of speculative

reason, and which afterwards became so celebrated under the name of

metaphysics.

I shall not at present indicate the periods of time at which the

greatest changes in metaphysics took place, but shall merely give a

hasty sketch of the different ideas which occasioned the most important

revolutions in this sphere of thought. There are three different ends

in relation to which these revolutions have taken place.

1. In relation to the object of the cognition of reason, philosophers

may be divided into sensualists and intellectualists. Epicurus may be

regarded as the head of the former, Plato of the latter. The

distinction here signalized, subtle as it is, dates from the earliest

times, and was long maintained. The former asserted that reality

resides in sensuous objects alone, and that everything else is merely

imaginary; the latter, that the senses are the parents of illusion and

that truth is to be found in the understanding alone. The former did

not deny to the conceptions of the understanding a certain kind of

reality; but with them it was merely logical, with the others it was

mystical. The former admitted intellectual conceptions, but declared

that sensuous objects alone possessed real existence. The latter

maintained that all real objects were intelligible, and believed that

the pure understanding possessed a faculty of intuition apart from

sense, which, in their opinion, served only to confuse the ideas of the

understanding.

2. In relation to the origin of the pure cognitions of reason, we find

one school maintaining that they are derived entirely from experience,

and another that they have their origin in reason alone. Aristotle

may be regarded as the head of the empiricists, and Plato of the

noologists. Locke, the follower of Aristotle in modern times, and

Leibnitz of Plato (although he cannot be said to have imitated him in

his mysticism), have not been able to bring this question to a settled

conclusion. The procedure of Epicurus in his sensual system, in which

he always restricted his conclusions to the sphere of experience, was

much more consequent than that of Aristotle and Locke. The latter

especially, after having derived all the conceptions and principles

of the mind from experience, goes so far, in the employment of these

conceptions and principles, as to maintain that we can prove the

existence of God and the immortality of the soul—both of them objects

lying beyond the limits of possible experience—with the same force of

demonstration, as any mathematical proposition.

3. In relation to method. Method is procedure according to principles.

We may divide the methods at present employed in the field of inquiry

into the naturalistic and the scientific. The naturalist of pure reason

lays it down as his principle that common reason, without the aid of

science—which he calls sound reason, or common sense—can give a more

satisfactory answer to the most important questions of metaphysics than

speculation is able to do. He must maintain, therefore, that we can

determine the content and circumference of the moon more certainly by

the naked eye, than by the aid of mathematical reasoning. But this

system is mere misology reduced to principles; and, what is the most

absurd thing in this doctrine, the neglect of all scientific means is

paraded as a peculiar method of extending our cognition. As regards

those who are naturalists because they know no better, they are

certainly not to be blamed. They follow common sense, without parading

their ignorance as a method which is to teach us the wonderful secret,

how we are to find the truth which lies at the bottom of the well of

Democritus.

Quod sapio satis est mihi, non ego curo Esse quod

Arcesilas aerumnosique Solones. PERSIUS

—Satirae, iii. 78-79.

is their motto, under which they may lead a pleasant and praiseworthy

life, without troubling themselves with science or troubling science

with them.

As regards those who wish to pursue a scientific method, they have now

the choice of following either the dogmatical or the sceptical, while

they are bound never to desert the systematic mode of procedure. When I

mention, in relation to the former, the celebrated Wolf, and as regards

the latter, David Hume, I may leave, in accordance with my present

intention, all others unnamed. The critical path alone is still open.

If my reader has been kind and patient enough to accompany me on this

hitherto untravelled route, he can now judge whether, if he and others

will contribute their exertions towards making this narrow footpath a

high road of thought, that which many centuries have failed to

accomplish may not be executed before the close of the present—namely,

to bring Reason to perfect contentment in regard to that which has

always, but without permanent results, occupied her powers and engaged

her ardent desire for knowledge.