The Critique of Pure Reason - Transcendental Doctrine of Method - The Discipline of Pure Reason.

Immanuel Kant (1724-1804)

            CHAPTER I. The Discipline of Pure Reason.



  Negative judgements- those which are so not merely as regards

their logical form, but in respect of their content- are not

commonly held in especial respect. They are, on the contrary, regarded

as jealous enemies of our insatiable desire for knowledge; and it

almost requires an apology to induce us to tolerate, much less to

prize and to respect them.

  All propositions, indeed, may be logically expressed in a negative

form; but, in relation to the content of our cognition, the peculiar

province of negative judgements is solely to prevent error. For this

reason, too, negative propositions, which are framed for the purpose

of correcting false cognitions where error is absolutely impossible,

are undoubtedly true, but inane and senseless; that is, they are in

reality purposeless and, for this reason, often very ridiculous.

Such is the proposition of the schoolman that Alexander could not have

subdued any countries without an army.

  But where the limits of our possible cognition are very much

contracted, the attraction to new fields of knowledge great, the

illusions to which the mind is subject of the most deceptive

character, and the evil consequences of error of no inconsiderable

magnitude- the negative element in knowledge, which is useful only

to guard us against error, is of far more importance than much of that

positive instruction which makes additions to the sum of our

knowledge. The restraint which is employed to repress, and finally

to extirpate the constant inclination to depart from certain rules, is

termed discipline. It is distinguished from culture, which aims at the

formation of a certain degree of skill, without attempting to

repress or to destroy any other mental power, already existing. In the

cultivation of a talent, which has given evidence of an impulse

towards self-development, discipline takes a negative,* culture and

doctrine a positive, part.



  *I am well aware that, in the language of the schools, the term

discipline is usually employed as synonymous with instruction. But

there are so many cases in which it is necessary to distinguish the

notion of the former, as a course of corrective training, from that of

the latter, as the communication of knowledge, and the nature of

things itself demands the appropriation of the most suitable

expressions for this distinction, that it is my desire that the former

terms should never be employed in any other than a negative

signification.



  That natural dispositions and talents (such as imagination and with,

which ask a free and unlimited development, require in many respects

the corrective influence of discipline, every one will readily

grant. But it may well appear strange that reason, whose proper duty

it is to prescribe rules of discipline to all the other powers of

the mind, should itself require this corrective. It has, in fact,

hitherto escaped this humiliation, only because, in presence of its

magnificent pretensions and high position, no one could readily

suspect it to be capable of substituting fancies for conceptions,

and words for things.

  Reason, when employed in the field of experience, does not stand

in need of criticism, because its principles are subjected to the

continual test of empirical observations. Nor is criticism requisite

in the sphere of mathematics, where the conceptions of reason must

always be presented in concreto in pure intuition, and baseless or

arbitrary assertions are discovered without difficulty. But where

reason is not held in a plain track by the influence of empirical or

of pure intuition, that is, when it is employed in the

transcendental sphere of pure conceptions, it stands in great need

of discipline, to restrain its propensity to overstep the limits of

possible experience and to keep it from wandering into error. In fact,

the utility of the philosophy of pure reason is entirely of this

negative character. Particular errors may be corrected by particular

animadversions, and the causes of these errors may be eradicated by

criticism. But where we find, as in the case of pure reason, a

complete system of illusions and fallacies, closely connected with

each other and depending upon grand general principles, there seems to

be required a peculiar and negative code of mental legislation, which,

under the denomination of a discipline, and founded upon the nature of

reason and the objects of its exercise, shall constitute a system of

thorough examination and testing, which no fallacy will be able to

withstand or escape from, under whatever disguise or concealment it

may lurk.

  But the reader must remark that, in this the second division of

our transcendental Critique the discipline of pure reason is not

directed to the content, but to the method of the cognition of pure

reason. The former task has been completed in the doctrine of

elements. But there is so much similarity in the mode of employing the

faculty of reason, whatever be the object to which it is applied,

while, at the same time, its employment in the transcendental sphere

is so essentially different in kind from every other, that, without

the warning negative influence of a discipline specially directed to

that end, the errors are unavoidable which spring from the

unskillful employment of the methods which are originated by reason

but which are out of place in this sphere.



     SECTION I. The Discipline of Pure Reason in the Sphere

                       of Dogmatism.



  The science of mathematics presents the most brilliant example of

the extension of the sphere of pure reason without the aid of

experience. Examples are always contagious; and they exert an especial

influence on the same faculty, which naturally flatters itself that it

will have the same good fortune in other case as fell to its lot in

one fortunate instance. Hence pure reason hopes to be able to extend

its empire in the transcendental sphere with equal success and

security, especially when it applies the same method which was

attended with such brilliant results in the science of mathematics. It

is, therefore, of the highest importance for us to know whether the

method of arriving at demonstrative certainty, which is termed

mathematical, be identical with that by which we endeavour to attain

the same degree of certainty in philosophy, and which is termed in

that science dogmatical.

  Philosophical cognition is the cognition of reason by means of

conceptions; mathematical cognition is cognition by means of the

construction of conceptions. The construction of a conception is the

presentation a priori of the intuition which corresponds to the

conception. For this purpose a non-empirical intuition is requisite,

which, as an intuition, is an individual object; while, as the

construction of a conception (a general representation), it must be

seen to be universally valid for all the possible intuitions which

rank under that conception. Thus I construct a triangle, by the

presentation of the object which corresponds to this conception,

either by mere imagination, in pure intuition, or upon paper, in

empirical intuition, in both cases completely a priori, without

borrowing the type of that figure from any experience. The

individual figure drawn upon paper is empirical; but it serves,

notwithstanding, to indicate the conception, even in its universality,

because in this empirical intuition we keep our eye merely on the

act of the construction of the conception, and pay no attention to the

various modes of determining it, for example, its size, the length

of its sides, the size of its angles, these not in the least affecting

the essential character of the conception.

  Philosophical cognition, accordingly, regards the particular only in

the general; mathematical the general in the particular, nay, in the

individual. This is done, however, entirely a priori and by means of

pure reason, so that, as this individual figure is determined under

certain universal conditions of construction, the object of the

conception, to which this individual figure corresponds as its schema,

must be cogitated as universally determined.

  The essential difference of these two modes of cognition consists,

therefore, in this formal quality; it does not regard the difference

of the matter or objects of both. Those thinkers who aim at

distinguishing philosophy from mathematics by asserting that the

former has to do with quality merely, and the latter with quantity,

have mistaken the effect for the cause. The reason why mathematical

cognition can relate only to quantity is to be found in its form

alone. For it is the conception of quantities only that is capable

of being constructed, that is, presented a priori in intuition;

while qualities cannot be given in any other than an empirical

intuition. Hence the cognition of qualities by reason is possible only

through conceptions. No one can find an intuition which shall

correspond to the conception of reality, except in experience; it

cannot be presented to the mind a priori and antecedently to the

empirical consciousness of a reality. We can form an intuition, by

means of the mere conception of it, of a cone, without the aid of

experience; but the colour of the cone we cannot know except from

experience. I cannot present an intuition of a cause, except in an

example which experience offers to me. Besides, philosophy, as well as

mathematics, treats of quantities; as, for example, of totality,

infinity, and so on. Mathematics, too, treats of the difference of

lines and surfaces- as spaces of different quality, of the

continuity of extension- as a quality thereof. But, although in such

cases they have a common object, the mode in which reason considers

that object is very different in philosophy from what it is in

mathematics. The former confines itself to the general conceptions;

the latter can do nothing with a mere conception, it hastens to

intuition. In this intuition it regards the conception in concreto,

not empirically, but in an a priori intuition, which it has

constructed; and in which, all the results which follow from the

general conditions of the construction of the conception are in all

cases valid for the object of the constructed conception.

  Suppose that the conception of a triangle is given to a

philosopher and that he is required to discover, by the

philosophical method, what relation the sum of its angles bears to a

right angle. He has nothing before him but the conception of a

figure enclosed within three right lines, and, consequently, with

the same number of angles. He may analyse the conception of a right

line, of an angle, or of the number three as long as he pleases, but

he will not discover any properties not contained in these

conceptions. But, if this question is proposed to a geometrician, he

at once begins by constructing a triangle. He knows that two right

angles are equal to the sum of all the contiguous angles which proceed

from one point in a straight line; and he goes on to produce one

side of his triangle, thus forming two adjacent angles which are

together equal to two right angles. He then divides the exterior of

these angles, by drawing a line parallel with the opposite side of the

triangle, and immediately perceives that be has thus got an exterior

adjacent angle which is equal to the interior. Proceeding in this way,

through a chain of inferences, and always on the ground of

intuition, he arrives at a clear and universally valid solution of the

question.

  But mathematics does not confine itself to the construction of

quantities (quanta), as in the case of geometry; it occupies itself

with pure quantity also (quantitas), as in the case of algebra,

where complete abstraction is made of the properties of the object

indicated by the conception of quantity. In algebra, a certain

method of notation by signs is adopted, and these indicate the

different possible constructions of quantities, the extraction of

roots, and so on. After having thus denoted the general conception

of quantities, according to their different relations, the different

operations by which quantity or number is increased or diminished

are presented in intuition in accordance with general rules. Thus,

when one quantity is to be divided by another, the signs which

denote both are placed in the form peculiar to the operation of

division; and thus algebra, by means of a symbolical construction of

quantity, just as geometry, with its ostensive or geometrical

construction (a construction of the objects themselves), arrives at

results which discursive cognition cannot hope to reach by the aid

of mere conceptions.

  Now, what is the cause of this difference in the fortune of the

philosopher and the mathematician, the former of whom follows the path

of conceptions, while the latter pursues that of intuitions, which

he represents, a priori, in correspondence with his conceptions? The

cause is evident from what has been already demonstrated in the

introduction to this Critique. We do not, in the present case, want to

discover analytical propositions, which may be produced merely by

analysing our conceptions- for in this the philosopher would have

the advantage over his rival; we aim at the discovery of synthetical

propositions- such synthetical propositions, moreover, as can be

cognized a priori. I must not confine myself to that which I

actually cogitate in my conception of a triangle, for this is

nothing more than the mere definition; I must try to go beyond that,

and to arrive at properties which are not contained in, although

they belong to, the conception. Now, this is impossible, unless I

determine the object present to my mind according to the conditions,

either of empirical, or of pure, intuition. In the former case, I

should have an empirical proposition (arrived at by actual measurement

of the angles of the triangle), which would possess neither

universality nor necessity; but that would be of no value. In the

latter, I proceed by geometrical construction, by means of which I

collect, in a pure intuition, just as I would in an empirical

intuition, all the various properties which belong to the schema of

a triangle in general, and consequently to its conception, and thus

construct synthetical propositions which possess the attribute of

universality.

  It would be vain to philosophize upon the triangle, that is, to

reflect on it discursively; I should get no further than the

definition with which I had been obliged to set out. There are

certainly transcendental synthetical propositions which are framed

by means of pure conceptions, and which form the peculiar

distinction of philosophy; but these do not relate to any particular

thing, but to a thing in general, and enounce the conditions under

which the perception of it may become a part of possible experience.

But the science of mathematics has nothing to do with such

questions, nor with the question of existence in any fashion; it is

concerned merely with the properties of objects in themselves, only in

so far as these are connected with the conception of the objects.

  In the above example, we merely attempted to show the great

difference which exists between the discursive employment of reason in

the sphere of conceptions, and its intuitive exercise by means of

the construction of conceptions. The question naturally arises: What

is the cause which necessitates this twofold exercise of reason, and

how are we to discover whether it is the philosophical or the

mathematical method which reason is pursuing in an argument?

  All our knowledge relates, finally, to possible intuitions, for it

is these alone that present objects to the mind. An a priori or

non-empirical conception contains either a pure intuition- and in this

case it can be constructed; or it contains nothing but the synthesis

of possible intuitions, which are not given a priori. In this latter

case, it may help us to form synthetical a priori judgements, but only

in the discursive method, by conceptions, not in the intuitive, by

means of the construction of conceptions.

  The only a priori intuition is that of the pure form of phenomena-

space and time. A conception of space and time as quanta may be

presented a priori in intuition, that is, constructed, either alone

with their quality (figure), or as pure quantity (the mere synthesis

of the homogeneous), by means of number. But the matter of

phenomena, by which things are given in space and time, can be

presented only in perception, a posteriori. The only conception

which represents a priori this empirical content of phenomena is the

conception of a thing in general; and the a priori synthetical

cognition of this conception can give us nothing more than the rule

for the synthesis of that which may be contained in the

corresponding a posteriori perception; it is utterly inadequate to

present an a priori intuition of the real object, which must

necessarily be empirical.

  Synthetical propositions, which relate to things in general, an a

priori intuition of which is impossible, are transcendental. For

this reason transcendental propositions cannot be framed by means of

the construction of conceptions; they are a priori, and based entirely

on conceptions themselves. They contain merely the rule, by which we

are to seek in the world of perception or experience the synthetical

unity of that which cannot be intuited a priori. But they are

incompetent to present any of the conceptions which appear in them

in an a priori intuition; these can be given only a posteriori, in

experience, which, however, is itself possible only through these

synthetical principles.

  If we are to form a synthetical judgement regarding a conception, we

must go beyond it, to the intuition in which it is given. If we keep

to what is contained in the conception, the judgement is merely

analytical- it is merely an explanation of what we have cogitated in

the conception. But I can pass from the conception to the pure or

empirical intuition which corresponds to it. I can proceed to

examine my conception in concreto, and to cognize, either a priori

or a posterio, what I find in the object of the conception. The

former- a priori cognition- is rational-mathematical cognition by

means of the construction of the conception; the latter- a

posteriori cognition- is purely empirical cognition, which does not

possess the attributes of necessity and universality. Thus I may

analyse the conception I have of gold; but I gain no new information

from this analysis, I merely enumerate the different properties

which I had connected with the notion indicated by the word. My

knowledge has gained in logical clearness and arrangement, but no

addition has been made to it. But if I take the matter which is

indicated by this name, and submit it to the examination of my senses,

I am enabled to form several synthetical- although still empirical-

propositions. The mathematical conception of a triangle I should

construct, that is, present a priori in intuition, and in this way

attain to rational-synthetical cognition. But when the

transcendental conception of reality, or substance, or power is

presented to my mind, I find that it does not relate to or indicate

either an empirical or pure intuition, but that it indicates merely

the synthesis of empirical intuitions, which cannot of course be given

a priori. The synthesis in such a conception cannot proceed a

priori- without the aid of experience- to the intuition which

corresponds to the conception; and, for this reason, none of these

conceptions can produce a determinative synthetical proposition,

they can never present more than a principle of the synthesis* of

possible empirical intuitions. A transcendental proposition is,

therefore, a synthetical cognition of reason by means of pure

conceptions and the discursive method, and it renders possible all

synthetical unity in empirical cognition, though it cannot present

us with any intuition a priori.



  *In the case of the conception of cause, I do really go beyond the

empirical conception of an event- but not to the intuition which

presents this conception in concreto, but only to the time-conditions,

which may be found in experience to correspond to the conception. My

procedure is, therefore, strictly according to conceptions; I cannot

in a case of this kind employ the construction of conceptions, because

the conception is merely a rule for the synthesis of perceptions,

which are not pure intuitions, and which, therefore, cannot be given a

priori.



  There is thus a twofold exercise of reason. Both modes have the

properties of universality and an a priori origin in common, but

are, in their procedure, of widely different character. The reason

of this is that in the world of phenomena, in which alone objects

are presented to our minds, there are two main elements- the form of

intuition (space and time), which can be cognized and determined

completely a priori, and the matter or content- that which is

presented in space and time, and which, consequently, contains a

something- an existence corresponding to our powers of sensation. As

regards the latter, which can never be given in a determinate mode

except by experience, there are no a priori notions which relate to

it, except the undetermined conceptions of the synthesis of possible

sensations, in so far as these belong (in a possible experience) to

the unity of consciousness. As regards the former, we can determine

our conceptions a priori in intuition, inasmuch as we are ourselves

the creators of the objects of the conceptions in space and time-

these objects being regarded simply as quanta. In the one case, reason

proceeds according to conceptions and can do nothing more than subject

phenomena to these- which can only be determined empirically, that is,

a posteriori- in conformity, however, with those conceptions as the

rules of all empirical synthesis. In the other case, reason proceeds

by the construction of conceptions; and, as these conceptions relate

to an a priori intuition, they may be given and determined in pure

intuition a priori, and without the aid of empirical data. The

examination and consideration of everything that exists in space or

time- whether it is a quantum or not, in how far the particular

something (which fills space or time) is a primary substratum, or a

mere determination of some other existence, whether it relates to

anything else- either as cause or effect, whether its existence is

isolated or in reciprocal connection with and dependence upon

others, the possibility of this existence, its reality and necessity

or opposites- all these form part of the cognition of reason on the

ground of conceptions, and this cognition is termed philosophical. But

to determine a priori an intuition in space (its figure), to divide

time into periods, or merely to cognize the quantity of an intuition

in space and time, and to determine it by number- all this is an

operation of reason by means of the construction of conceptions, and

is called mathematical.

  The success which attends the efforts of reason in the sphere of

mathematics naturally fosters the expectation that the same good

fortune will be its lot, if it applies the mathematical method in

other regions of mental endeavour besides that of quantities. Its

success is thus great, because it can support all its conceptions by a

priori intuitions and, in this way, make itself a master, as it

were, over nature; while pure philosophy, with its a priori discursive

conceptions, bungles about in the world of nature, and cannot accredit

or show any a priori evidence of the reality of these conceptions.

Masters in the science of mathematics are confident of the success

of this method; indeed, it is a common persuasion that it is capable

of being applied to any subject of human thought. They have hardly

ever reflected or philosophized on their favourite science- a task

of great difficulty; and the specific difference between the two modes

of employing the faculty of reason has never entered their thoughts.

Rules current in the field of common experience, and which common

sense stamps everywhere with its approval, are regarded by them as

axiomatic. From what source the conceptions of space and time, with

which (as the only primitive quanta) they have to deal, enter their

minds, is a question which they do not trouble themselves to answer;

and they think it just as unnecessary to examine into the origin of

the pure conceptions of the understanding and the extent of their

validity. All they have to do with them is to employ them. In all this

they are perfectly right, if they do not overstep the limits of the

sphere of nature. But they pass, unconsciously, from the world of

sense to the insecure ground of pure transcendental conceptions

(instabilis tellus, innabilis unda), where they can neither stand

nor swim, and where the tracks of their footsteps are obliterated by

time; while the march of mathematics is pursued on a broad and

magnificent highway, which the latest posterity shall frequent without

fear of danger or impediment.

  As we have taken upon us the task of determining, clearly and

certainly, the limits of pure reason in the sphere of

transcendentalism, and as the efforts of reason in this direction

are persisted in, even after the plainest and most expressive

warnings, hope still beckoning us past the limits of experience into

the splendours of the intellectual world- it becomes necessary to

cut away the last anchor of this fallacious and fantastic hope. We

shall, accordingly, show that the mathematical method is unattended in

the sphere of philosophy by the least advantage- except, perhaps, that

it more plainly exhibits its own inadequacy- that geometry and

philosophy are two quite different things, although they go band in

hand in hand in the field of natural science, and, consequently,

that the procedure of the one can never be imitated by the other.

  The evidence of mathematics rests upon definitions, axioms, and

demonstrations. I shall be satisfied with showing that none of these

forms can be employed or imitated in philosophy in the sense in

which they are understood by mathematicians; and that the

geometrician, if he employs his method in philosophy, will succeed

only in building card-castles, while the employment of the

philosophical method in mathematics can result in nothing but mere

verbiage. The essential business of philosophy, indeed, is to mark out

the limits of the science; and even the mathematician, unless his

talent is naturally circumscribed and limited to this particular

department of knowledge, cannot turn a deaf ear to the warnings of

philosophy, or set himself above its direction.

  I. Of Definitions. A definition is, as the term itself indicates,

the representation, upon primary grounds, of the complete conception

of a thing within its own limits.* Accordingly, an empirical

conception cannot be defined, it can only be explained. For, as

there are in such a conception only a certain number of marks or

signs, which denote a certain class of sensuous objects, we can

never be sure that we do not cogitate under the word which indicates

the same object, at one time a greater, at another a smaller number of

signs. Thus, one person may cogitate in his conception of gold, in

addition to its properties of weight, colour, malleability, that of

resisting rust, while another person may be ignorant of this

quality. We employ certain signs only so long as we require them for

the sake of distinction; new observations abstract some and add new

ones, so that an empirical conception never remains within permanent

limits. It is, in fact, useless to define a conception of this kind.

If, for example, we are speaking of water and its properties, we do

not stop at what we actually think by the word water, but proceed to

observation and experiment; and the word, with the few signs

attached to it, is more properly a designation than a conception of

the thing. A definition in this case would evidently be nothing more

than a determination of the word. In the second place, no a priori

conception, such as those of substance, cause, right, fitness, and

so on, can be defined. For I can never be sure, that the clear

representation of a given conception (which is given in a confused

state) has been fully developed, until I know that the

representation is adequate with its object. But, inasmuch as the

conception, as it is presented to the mind, may contain a number of

obscure representations, which we do not observe in our analysis,

although we employ them in our application of the conception, I can

never be sure that my analysis is complete, while examples may make

this probable, although they can never demonstrate the fact. instead

of the word definition, I should rather employ the term exposition-

a more modest expression, which the critic may accept without

surrendering his doubts as to the completeness of the analysis of

any such conception. As, therefore, neither empirical nor a priori

conceptions are capable of definition, we have to see whether the only

other kind of conceptions- arbitrary conceptions- can be subjected

to this mental operation. Such a conception can always be defined; for

I must know thoroughly what I wished to cogitate in it, as it was I

who created it, and it was not given to my mind either by the nature

of my understanding or by experience. At the same time, I cannot say

that, by such a definition, I have defined a real object. If the

conception is based upon empirical conditions, if, for example, I have

a conception of a clock for a ship, this arbitrary conception does not

assure me of the existence or even of the possibility of the object.

My definition of such a conception would with more propriety be termed

a declaration of a project than a definition of an object. There

are no other conceptions which can bear definition, except those which

contain an arbitrary synthesis, which can be constructed a priori.

Consequently, the science of mathematics alone possesses

definitions. For the object here thought is presented a priori in

intuition; and thus it can never contain more or less than the

conception, because the conception of the object has been given by the

definition- and primarily, that is, without deriving the definition

from any other source. Philosophical definitions are, therefore,

merely expositions of given conceptions, while mathematical

definitions are constructions of conceptions originally formed by

the mind itself; the former are produced by analysis, the completeness

of which is never demonstratively certain, the latter by a

synthesis. In a mathematical definition the conception is formed, in a

philosophical definition it is only explained. From this it follows:



  *The definition must describe the conception completely that is,

omit none of the marks or signs of which it composed; within its own

limits, that is, it must be precise, and enumerate no more signs

than belong to the conception; and on primary grounds, that is to say,

the limitations of the bounds of the conception must not be deduced

from other conceptions, as in this case a proof would be necessary,

and the so-called definition would be incapable of taking its place at

the bead of all the judgements we have to form regarding an object.



  (a) That we must not imitate, in philosophy, the mathematical

usage of commencing with definitions- except by way of hypothesis or

experiment. For, as all so-called philosophical definitions are merely

analyses of given conceptions, these conceptions, although only in a

confused form, must precede the analysis; and the incomplete

exposition must precede the complete, so that we may be able to draw

certain inferences from the characteristics which an incomplete

analysis has enabled us to discover, before we attain to the

complete exposition or definition of the conception. In one word, a

full and clear definition ought, in philosophy, rather to form the

conclusion than the commencement of our labours.* In mathematics, on

the contrary, we cannot have a conception prior to the definition;

it is the definition which gives us the conception, and it must for

this reason form the commencement of every chain of mathematical

reasoning.



  *Philosophy abounds in faulty definitions, especially such as

contain some of the elements requisite to form a complete

definition. If a conception could not be employed in reasoning

before it had been defined, it would fare ill with all philosophical

thought. But, as incompletely defined conceptions may always be

employed without detriment to truth, so far as our analysis of the

elements contained in them proceeds, imperfect definitions, that is,

propositions which are properly not definitions, but merely

approximations thereto, may be used with great advantage. In

mathematics, definition belongs ad esse, in philosophy ad melius esse.

It is a difficult task to construct a proper definition. Jurists are

still without a complete definition of the idea of right.



  (b) Mathematical definitions cannot be erroneous. For the conception

is given only in and through the definition, and thus it contains only

what has been cogitated in the definition. But although a definition

cannot be incorrect, as regards its content, an error may sometimes,

although seldom, creep into the form. This error consists in a want of

precision. Thus the common definition of a circle- that it is a curved

line, every point in which is equally distant from another point

called the centre- is faulty, from the fact that the determination

indicated by the word curved is superfluous. For there ought to be a

particular theorem, which may be easily proved from the definition, to

the effect that every line, which has all its points at equal

distances from another point, must be a curved line- that is, that not

even the smallest part of it can be straight. Analytical

definitions, on the other hand, may be erroneous in many respects,

either by the introduction of signs which do not actually exist in the

conception, or by wanting in that completeness which forms the

essential of a definition. In the latter case, the definition is

necessarily defective, because we can never be fully certain of the

completeness of our analysis. For these reasons, the method of

definition employed in mathematics cannot be imitated in philosophy.

  2. Of Axioms. These, in so far as they are immediately certain,

are a priori synthetical principles. Now, one conception cannot be

connected synthetically and yet immediately with another; because,

if we wish to proceed out of and beyond a conception, a third

mediating cognition is necessary. And, as philosophy is a cognition of

reason by the aid of conceptions alone, there is to be found in it

no principle which deserves to be called an axiom. Mathematics, on the

other hand, may possess axioms, because it can always connect the

predicates of an object a priori, and without any mediating term, by

means of the construction of conceptions in intuition. Such is the

case with the proposition: Three points can always lie in a plane.

On the other hand, no synthetical principle which is based upon

conceptions, can ever be immediately certain (for example, the

proposition: Everything that happens has a cause), because I require a

mediating term to connect the two conceptions of event and cause-

namely, the condition of time-determination in an experience, and I

cannot cognize any such principle immediately and from conceptions

alone. Discursive principles are, accordingly, very different from

intuitive principles or axioms. The former always require deduction,

which in the case of the latter may be altogether dispensed with.

Axioms are, for this reason, always self-evident, while

philosophical principles, whatever may be the degree of certainty they

possess, cannot lay any claim to such a distinction. No synthetical

proposition of pure transcendental reason can be so evident, as is

often rashly enough declared, as the statement, twice two are four. It

is true that in the Analytic I introduced into the list of

principles of the pure understanding, certain axioms of intuition; but

the principle there discussed was not itself an axiom, but served

merely to present the principle of the possibility of axioms in

general, while it was really nothing more than a principle based

upon conceptions. For it is one part of the duty of transcendental

philosophy to establish the possibility of mathematics itself.

Philosophy possesses, then, no axioms, and has no right to impose

its a priori principles upon thought, until it has established their

authority and validity by a thoroughgoing deduction.

  3. Of Demonstrations. Only an apodeictic proof, based upon

intuition, can be termed a demonstration. Experience teaches us what

is, but it cannot convince us that it might not have been otherwise.

Hence a proof upon empirical grounds cannot be apodeictic. A priori

conceptions, in discursive cognition, can never produce intuitive

certainty or evidence, however certain the judgement they present

may be. Mathematics alone, therefore, contains demonstrations, because

it does not deduce its cognition from conceptions, but from the

construction of conceptions, that is, from intuition, which can be

given a priori in accordance with conceptions. The method of

algebra, in equations, from which the correct answer is deduced by

reduction, is a kind of construction- not geometrical, but by symbols-

in which all conceptions, especially those of the relations of

quantities, are represented in intuition by signs; and thus the

conclusions in that science are secured from errors by the fact that

every proof is submitted to ocular evidence. Philosophical cognition

does not possess this advantage, it being required to consider the

general always in abstracto (by means of conceptions), while

mathematics can always consider it in concreto (in an individual

intuition), and at the same time by means of a priori

representation, whereby all errors are rendered manifest to the

senses. The former- discursive proofs- ought to be termed acroamatic

proofs, rather than demonstrations, as only words are employed in

them, while demonstrations proper, as the term itself indicates,

always require a reference to the intuition of the object.

  It follows from all these considerations that it is not consonant

with the nature of philosophy, especially in the sphere of pure

reason, to employ the dogmatical method, and to adorn itself with

the titles and insignia of mathematical science. It does not belong to

that order, and can only hope for a fraternal union with that science.

Its attempts at mathematical evidence are vain pretensions, which

can only keep it back from its true aim, which is to detect the

illusory procedure of reason when transgressing its proper limits, and

by fully explaining and analysing our conceptions, to conduct us

from the dim regions of speculation to the clear region of modest

self-knowledge. Reason must not, therefore, in its transcendental

endeavours, look forward with such confidence, as if the path it is

pursuing led straight to its aim, nor reckon with such security upon

its premisses, as to consider it unnecessary to take a step back, or

to keep a strict watch for errors, which, overlooked in the

principles, may be detected in the arguments themselves- in which case

it may be requisite either to determine these principles with

greater strictness, or to change them entirely.

  I divide all apodeictic propositions, whether demonstrable or

immediately certain, into dogmata and mathemata. A direct

synthetical proposition, based on conceptions, is a dogma; a

proposition of the same kind, based on the construction of

conceptions, is a mathema. Analytical judgements do not teach us any

more about an object than what was contained in the conception we

had of it; because they do not extend our cognition beyond our

conception of an object, they merely elucidate the conception. They

cannot therefore be with propriety termed dogmas. Of the two kinds

of a priori synthetical propositions above mentioned, only those which

are employed in philosophy can, according to the general mode of

speech, bear this name; those of arithmetic or geometry would not be

rightly so denominated. Thus the customary mode of speaking confirms

the explanation given above, and the conclusion arrived at, that

only those judgements which are based upon conceptions, not on the

construction of conceptions, can be termed dogmatical.

  Thus, pure reason, in the sphere of speculation, does not contain

a single direct synthetical judgement based upon conceptions. By means

of ideas, it is, as we have shown, incapable of producing

synthetical judgements, which are objectively valid; by means of the

conceptions of the understanding, it establishes certain indubitable

principles, not, however, directly on the basis of conceptions, but

only indirectly by means of the relation of these conceptions to

something of a purely contingent nature, namely, possible

experience. When experience is presupposed, these principles are

apodeictically certain, but in themselves, and directly, they cannot

even be cognized a priori. Thus the given conceptions of cause and

event will not be sufficient for the demonstration of the proposition:

Every event has a cause. For this reason, it is not a dogma;

although from another point of view, that of experience, it is capable

of being proved to demonstration. The proper term for such a

proposition is principle, and not theorem (although it does require to

be proved), because it possesses the remarkable peculiarity of being

the condition of the possibility of its own ground of proof, that

is, experience, and of forming a necessary presupposition in all

empirical observation.

  If then, in the speculative sphere of pure reason, no dogmata are to

be found; all dogmatical methods, whether borrowed from mathematics,

or invented by philosophical thinkers, are alike inappropriate and

inefficient. They only serve to conceal errors and fallacies, and to

deceive philosophy, whose duty it is to see that reason pursues a safe

and straight path. A philosophical method may, however, be

systematical. For our reason is, subjectively considered, itself a

system, and, in the sphere of mere conceptions, a system of

investigation according to principles of unity, the material being

supplied by experience alone. But this is not the proper place for

discussing the peculiar method of transcendental philosophy, as our

present task is simply to examine whether our faculties are capable of

erecting an edifice on the basis of pure reason, and how far they

may proceed with the materials at their command.



     SECTION II. The Discipline of Pure Reason in Polemics.



  Reason must be subject, in all its operations, to criticism, which

must always be permitted to exercise its functions without

restraint; otherwise its interests are imperilled and its influence

obnoxious to suspicion. There is nothing, however useful, however

sacred it may be, that can claim exemption from the searching

examination of this supreme tribunal, which has no respect of persons.

The very existence of reason depends upon this freedom; for the

voice of reason is not that of a dictatorial and despotic power, it is

rather like the vote of the citizens of a free state, every member

of which must have the privilege of giving free expression to his

doubts, and possess even the right of veto.

  But while reason can never decline to submit itself to the

tribunal of criticism, it has not always cause to dread the

judgement of this court. Pure reason, however, when engaged in the

sphere of dogmatism, is not so thoroughly conscious of a strict

observance of its highest laws, as to appear before a higher

judicial reason with perfect confidence. On the contrary, it must

renounce its magnificent dogmatical pretensions in philosophy.

  Very different is the case when it has to defend itself, not

before a judge, but against an equal. If dogmatical assertions are

advanced on the negative side, in opposition to those made by reason

on the positive side, its justification kat authrhopon is complete,

although the proof of its propositions is kat aletheian

unsatisfactory.

  By the polemic of pure reason I mean the defence of its propositions

made by reason, in opposition to the dogmatical counter-propositions

advanced by other parties. The question here is not whether its own

statements may not also be false; it merely regards the fact that

reason proves that the opposite cannot be established with

demonstrative certainty, nor even asserted with a higher degree of

probability. Reason does not hold her possessions upon sufferance;

for, although she cannot show a perfectly satisfactory title to

them, no one can prove that she is not the rightful possessor.

  It is a melancholy reflection that reason, in its highest

exercise, falls into an antithetic; and that the supreme tribunal

for the settlement of differences should not be at union with

itself. It is true that we had to discuss the question of an

apparent antithetic, but we found that it was based upon a

misconception. In conformity with the common prejudice, phenomena were

regarded as things in themselves, and thus an absolute completeness in

their synthesis was required in the one mode or in the other (it was

shown to be impossible in both); a demand entirely out of place in

regard to phenomena. There was, then, no real self-contradiction of

reason in the propositions: The series of phenomena given in

themselves has an absolutely first beginning; and: This series is

absolutely and in itself without beginning. The two propositions are

perfectly consistent with each other, because phenomena as phenomena

are in themselves nothing, and consequently the hypothesis that they

are things in themselves must lead to self-contradictory inferences.

  But there are cases in which a similar misunderstanding cannot be

provided against, and the dispute must remain unsettled. Take, for

example, the theistic proposition: There is a Supreme Being; and on

the other hand, the atheistic counter-statement: There exists no

Supreme Being; or, in psychology: Everything that thinks possesses the

attribute of absolute and permanent unity, which is utterly

different from the transitory unity of material phenomena; and the

counter-proposition: The soul is not an immaterial unity, and its

nature is transitory, like that of phenomena. The objects of these

questions contain no heterogeneous or contradictory elements, for they

relate to things in themselves, and not to phenomena. There would

arise, indeed, a real contradiction, if reason came forward with a

statement on the negative side of these questions alone. As regards

the criticism to which the grounds of proof on the affirmative side

must be subjected, it may be freely admitted, without necessitating

the surrender of the affirmative propositions, which have, at least,

the interest of reason in their favour- an advantage which the

opposite party cannot lay claim to.

  I cannot agree with the opinion of several admirable thinkers-

Sulzer among the rest- that, in spite of the weakness of the arguments

hitherto in use, we may hope, one day, to see sufficient

demonstrations of the two cardinal propositions of pure reason- the

existence of a Supreme Being, and the immortality of the soul. I am

certain, on the contrary, that this will never be the case. For on

what ground can reason base such synthetical propositions, which do

not relate to the objects of experience and their internal

possibility? But it is also demonstratively certain that no one will

ever be able to maintain the contrary with the least show of

probability. For, as he can attempt such a proof solely upon the basis

of pure reason, he is bound to prove that a Supreme Being, and a

thinking subject in the character of a pure intelligence, are

impossible. But where will he find the knowledge which can enable

him to enounce synthetical judgements in regard to things which

transcend the region of experience? We may, therefore, rest assured

that the opposite never will be demonstrated. We need not, then,

have recourse to scholastic arguments; we may always admit the truth

of those propositions which are consistent with the speculative

interests of reason in the sphere of experience, and form, moreover,

the only means of uniting the speculative with the practical interest.

Our opponent, who must not be considered here as a critic solely, we

can be ready to meet with a non liquet which cannot fail to disconcert

him; while we cannot deny his right to a similar retort, as we have on

our side the advantage of the support of the subjective maxim of

reason, and can therefore look upon all his sophistical arguments with

calm indifference.

  From this point of view, there is properly no antithetic of pure

reason. For the only arena for such a struggle would be upon the field

of pure theology and psychology; but on this ground there can appear

no combatant whom we need to fear. Ridicule and boasting can be his

only weapons; and these may be laughed at, as mere child's play.

This consideration restores to Reason her courage; for what source

of confidence could be found, if she, whose vocation it is to

destroy error, were at variance with herself and without any

reasonable hope of ever reaching a state of permanent repose?

  Everything in nature is good for some purpose. Even poisons are

serviceable; they destroy the evil effects of other poisons

generated in our system, and must always find a place in every

complete pharmacopoeia. The objections raised against the fallacies

and sophistries of speculative reason, are objections given by the

nature of this reason itself, and must therefore have a destination

and purpose which can only be for the good of humanity. For what

purpose has Providence raised many objects, in which we have the

deepest interest, so far above us, that we vainly try to cognize

them with certainty, and our powers of mental vision are rather

excited than satisfied by the glimpses we may chance to seize? It is

very doubtful whether it is for our benefit to advance bold

affirmations regarding subjects involved in such obscurity; perhaps it

would even be detrimental to our best interests. But it is undoubtedly

always beneficial to leave the investigating, as well as the

critical reason, in perfect freedom, and permit it to take charge of

its own interests, which are advanced as much by its limitation, as by

its extension of its views, and which always suffer by the

interference of foreign powers forcing it, against its natural

tendencies, to bend to certain preconceived designs.

  Allow your opponent to say what he thinks reasonable, and combat him

only with the weapons of reason. Have no anxiety for the practical

interests of humanity- these are never imperilled in a purely

speculative dispute. Such a dispute serves merely to disclose the

antinomy of reason, which, as it has its source in the nature of

reason, ought to be thoroughly investigated. Reason is benefited by

the examination of a subject on both sides, and its judgements are

corrected by being limited. It is not the matter that may give

occasion to dispute, but the manner. For it is perfectly permissible

to employ, in the presence of reason, the language of a firmly

rooted faith, even after we have been obliged to renounce all

pretensions to knowledge.

  If we were to ask the dispassionate David Hume- a philosopher

endowed, in a degree that few are, with a well-balanced judgement:

What motive induced you to spend so much labour and thought in

undermining the consoling and beneficial persuasion that reason is

capable of assuring us of the existence, and presenting us with a

determinate conception of a Supreme Being?- his answer would be:

Nothing but the desire of teaching reason to know its own powers

better, and, at the same time, a dislike of the procedure by which

that faculty was compelled to support foregone conclusions, and

prevented from confessing the internal weaknesses which it cannot

but feel when it enters upon a rigid self-examination. If, on the

other hand, we were to ask Priestley- a philosopher who had no taste

for transcendental speculation, but was entirely devoted to the

principles of empiricism- what his motives were for overturning

those two main pillars of religion- the doctrines of the freedom of

the will and the immortality of the soul (in his view the hope of a

future life is but the expectation of the miracle of resurrection)-

this philosopher, himself a zealous and pious teacher of religion,

could give no other answer than this: I acted in the interest of

reason, which always suffers, when certain objects are explained and

judged by a reference to other supposed laws than those of material

nature- the only laws which we know in a determinate manner. It

would be unfair to decry the latter philosopher, who endeavoured to

harmonize his paradoxical opinions with the interests of religion, and

to undervalue an honest and reflecting man, because he finds himself

at a loss the moment he has left the field of natural science. The

same grace must be accorded to Hume, a man not less well-disposed, and

quite as blameless in his moral character, and who pushed his abstract

speculations to an extreme length, because, as he rightly believed,

the object of them lies entirely beyond the bounds of natural science,

and within the sphere of pure ideas.

  What is to be done to provide against the danger which seems in

the present case to menace the best interests of humanity? The

course to be pursued in reference to this subject is a perfectly plain

and natural one. Let each thinker pursue his own path; if he shows

talent, if be gives evidence of profound thought, in one word, if he

shows that he possesses the power of reasoning- reason is always the

gainer. If you have recourse to other means, if you attempt to

coerce reason, if you raise the cry of treason to humanity, if you

excite the feelings of the crowd, which can neither understand nor

sympathize with such subtle speculations- you will only make

yourselves ridiculous. For the question does not concern the advantage

or disadvantage which we are expected to reap from such inquiries; the

question is merely how far reason can advance in the field of

speculation, apart from all kinds of interest, and whether we may

depend upon the exertions of speculative reason, or must renounce

all reliance on it. Instead of joining the combatants, it is your part

to be a tranquil spectator of the struggle- a laborious struggle for

the parties engaged, but attended, in its progress as well as in its

result, with the most advantageous consequences for the interests of

thought and knowledge. It is absurd to expect to be enlightened by

Reason, and at the same time to prescribe to her what side of the

question she must adopt. Moreover, reason is sufficiently held in

check by its own power, the limits imposed on it by its own nature are

sufficient; it is unnecessary for you to place over it additional

guards, as if its power were dangerous to the constitution of the

intellectual state. In the dialectic of reason there is no victory

gained which need in the least disturb your tranquility.

  The strife of dialectic is a necessity of reason, and we cannot

but wish that it had been conducted long ere this with that perfect

freedom which ought to be its essential condition. In this case, we

should have had at an earlier period a matured and profound criticism,

which must have put an end to all dialectical disputes, by exposing

the illusions and prejudices in which they originated.

  There is in human nature an unworthy propensity- a propensity which,

like everything that springs from nature, must in its final purpose be

conducive to the good of humanity- to conceal our real sentiments, and

to give expression only to certain received opinions, which are

regarded as at once safe and promotive of the common good. It is true,

this tendency, not only to conceal our real sentiments, but to profess

those which may gain us favour in the eyes of society, has not only

civilized, but, in a certain measure, moralized us; as no one can

break through the outward covering of respectability, honour, and

morality, and thus the seemingly-good examples which we which we see

around us form an excellent school for moral improvement, so long as

our belief in their genuineness remains unshaken. But this disposition

to represent ourselves as better than we are, and to utter opinions

which are not our own, can be nothing more than a kind of provisionary

arrangement of nature to lead us from the rudeness of an uncivilized

state, and to teach us how to assume at least the appearance and

manner of the good we see. But when true principles have been

developed, and have obtained a sure foundation in our habit of

thought, this conventionalism must be attacked with earnest vigour,

otherwise it corrupts the heart, and checks the growth of good

dispositions with the mischievous weed of air appearances.

  I am sorry to remark the same tendency to misrepresentation and

hypocrisy in the sphere of speculative discussion, where there is less

temptation to restrain the free expression of thought. For what can be

more prejudicial to the interests of intelligence than to falsify

our real sentiments, to conceal the doubts which we feel in regard

to our statements, or to maintain the validity of grounds of proof

which we well know to be insufficient? So long as mere personal vanity

is the source of these unworthy artifices- and this is generally the

case in speculative discussions, which are mostly destitute of

practical interest, and are incapable of complete demonstration- the

vanity of the opposite party exaggerates as much on the other side;

and thus the result is the same, although it is not brought about so

soon as if the dispute had been conducted in a sincere and upright

spirit. But where the mass entertains the notion that the aim of

certain subtle speculators is nothing less than to shake the very

foundations of public welfare and morality- it seems not only prudent,

but even praise worthy, to maintain the good cause by illusory

arguments, rather than to give to our supposed opponents the advantage

of lowering our declarations to the moderate tone of a merely

practical conviction, and of compelling us to confess our inability to

attain to apodeictic certainty in speculative subjects. But we ought

to reflect that there is nothing, in the world more fatal to the

maintenance of a good cause than deceit, misrepresentation, and

falsehood. That the strictest laws of honesty should be observed in

the discussion of a purely speculative subject is the least

requirement that can be made. If we could reckon with security even

upon so little, the conflict of speculative reason regarding the

important questions of God, immortality, and freedom, would have

been either decided long ago, or would very soon be brought to a

conclusion. But, in general, the uprightness of the defence stands

in an inverse ratio to the goodness of the cause; and perhaps more

honesty and fairness are shown by those who deny than by those who

uphold these doctrines.

  I shall persuade myself, then, that I have readers who do not wish

to see a righteous cause defended by unfair arguments. Such will now

recognize the fact that, according to the principles of this Critique,

if we consider not what is, but what ought to be the case, there can

be really no polemic of pure reason. For how can two persons dispute

about a thing, the reality of which neither can present in actual or

even in possible experience? Each adopts the plan of meditating on his

idea for the purpose of drawing from the idea, if he can, what is more

than the idea, that is, the reality of the object which it

indicates. How shall they settle the dispute, since neither is able to

make his assertions directly comprehensible and certain, but must

restrict himself to attacking and confuting those of his opponent? All

statements enounced by pure reason transcend the conditions of

possible experience, beyond the sphere of which we can discover no

criterion of truth, while they are at the same time framed in

accordance with the laws of the understanding, which are applicable

only to experience; and thus it is the fate of all such speculative

discussions that while the one party attacks the weaker side of his

opponent, he infallibly lays open his own weaknesses.

  The critique of pure reason may be regarded as the highest

tribunal for all speculative disputes; for it is not involved in these

disputes, which have an immediate relation to certain objects and

not to the laws of the mind, but is instituted for the purpose of

determining the rights and limits of reason.

  Without the control of criticism, reason is, as it were, in a

state of nature, and can only establish its claims and assertions by

war. Criticism, on the contrary, deciding all questions according to

the fundamental laws of its own institution, secures to us the peace

of law and order, and enables us to discuss all differences in the

more tranquil manner of a legal process. In the former case,

disputes are ended by victory, which both sides may claim and which is

followed by a hollow armistice; in the latter, by a sentence, which,

as it strikes at the root of all speculative differences, ensures to

all concerned a lasting peace. The endless disputes of a dogmatizing

reason compel us to look for some mode of arriving at a settled

decision by a critical investigation of reason itself; just as

Hobbes maintains that the state of nature is a state of injustice

and violence, and that we must leave it and submit ourselves to the

constraint of law, which indeed limits individual freedom, but only

that it may consist with the freedom of others and with the common

good of all.

  This freedom will, among other things, permit of our openly

stating the difficulties and doubts which we are ourselves unable to

solve, without being decried on that account as turbulent and

dangerous citizens. This privilege forms part of the native rights

of human reason, which recognizes no other judge than the universal

reason of humanity; and as this reason is the source of all progress

and improvement, such a privilege is to be held sacred and inviolable.

It is unwise, moreover, to denounce as dangerous any bold assertions

against, or rash attacks upon, an opinion which is held by the largest

and most moral class of the community; for that would be giving them

an importance which they do not deserve. When I hear that the

freedom of the will, the hope of a future life, and the existence of

God have been overthrown by the arguments of some able writer, I

feel a strong desire to read his book; for I expect that he will add

to my knowledge and impart greater clearness and distinctness to my

views by the argumentative power shown in his writings. But I am

perfectly certain, even before I have opened the book, that he has not

succeeded in a single point, not because I believe I am in

possession of irrefutable demonstrations of these important

propositions, but because this transcendental critique, which has

disclosed to me the power and the limits of pure reason, has fully

convinced me that, as it is insufficient to establish the affirmative,

it is as powerless, and even more so, to assure us of the truth of the

negative answer to these questions. From what source does this

free-thinker derive his knowledge that there is, for example, no

Supreme Being? This proposition lies out of the field of possible

experience, and, therefore, beyond the limits of human cognition.

But I would not read at, all the answer which the dogmatical

maintainer of the good cause makes to his opponent, because I know

well beforehand, that he will merely attack the fallacious grounds

of his adversary, without being able to establish his own

assertions. Besides, a new illusory argument, in the construction of

which talent and acuteness are shown, is suggestive of new ideas and

new trains of reasoning, and in this respect the old and everyday

sophistries are quite useless. Again, the dogmatical opponent of

religion gives employment to criticism, and enables us to test and

correct its principles, while there is no occasion for anxiety in

regard to the influence and results of his reasoning.

  But, it will be said, must we not warn the youth entrusted to

academical care against such writings, must we not preserve them

from the knowledge of these dangerous assertions, until their

judgement is ripened, or rather until the doctrines which we wish to

inculcate are so firmly rooted in their minds as to withstand all

attempts at instilling the contrary dogmas, from whatever quarter they

may come?

  If we are to confine ourselves to the dogmatical procedure in the

sphere of pure reason, and find ourselves unable to settle such

disputes otherwise than by becoming a party in them, and setting

counter-assertions against the statements advanced by our opponents,

there is certainly no plan more advisable for the moment, but, at

the same time, none more absurd and inefficient for the future, than

this retaining of the youthful mind under guardianship for a time, and

thus preserving it- for so long at least- from seduction into error.

But when, at a later period, either curiosity, or the prevalent

fashion of thought places such writings in their hands, will the

so-called convictions of their youth stand firm? The young thinker,

who has in his armoury none but dogmatical weapons with which to

resist the attacks of his opponent, and who cannot detect the latent

dialectic which lies in his own opinions as well as in those of the

opposite party, sees the advance of illusory arguments and grounds

of proof which have the advantage of novelty, against as illusory

grounds of proof destitute of this advantage, and which, perhaps,

excite the suspicion that the natural credulity of his youth has

been abused by his instructors. He thinks he can find no better

means of showing that he has out grown the discipline of his

minority than by despising those well-meant warnings, and, knowing

no system of thought but that of dogmatism, he drinks deep draughts of

the poison that is to sap the principles in which his early years were

trained.

  Exactly the opposite of the system here recommended ought to be

pursued in academical instruction. This can only be effected, however,

by a thorough training in the critical investigation of pure reason.

For, in order to bring the principles of this critique into exercise

as soon as possible, and to demonstrate their perfect even in the

presence of the highest degree of dialectical illusion, the student

ought to examine the assertions made on both sides of speculative

questions step by step, and to test them by these principles. It

cannot be a difficult task for him to show the fallacies inherent in

these propositions, and thus he begins early to feel his own power

of securing himself against the influence of such sophistical

arguments, which must finally lose, for him, all their illusory power.

And, although the same blows which overturn the edifice of his

opponent are as fatal to his own speculative structures, if such he

has wished to rear; he need not feel any sorrow in regard to this

seeming misfortune, as he has now before him a fair prospect into

the practical region in which he may reasonably hope to find a more

secure foundation for a rational system.

  There is, accordingly, no proper polemic in the sphere of pure

reason. Both parties beat the air and fight with their own shadows, as

they pass beyond the limits of nature, and can find no tangible

point of attack- no firm footing for their dogmatical conflict.

Fight as vigorously as they may, the shadows which they hew down,

immediately start up again, like the heroes in Walhalla, and renew the

bloodless and unceasing contest.

  But neither can we admit that there is any proper sceptical

employment of pure reason, such as might be based upon the principle

of neutrality in all speculative disputes. To excite reason against

itself, to place weapons in the hands of the party on the one side

as well as in those of the other, and to remain an undisturbed and

sarcastic spectator of the fierce struggle that ensues, seems, from

the dogmatical point of view, to be a part fitting only a malevolent

disposition. But, when the sophist evidences an invincible obstinacy

and blindness, and a pride which no criticism can moderate, there is

no other practicable course than to oppose to this pride and obstinacy

similar feelings and pretensions on the other side, equally well or

ill founded, so that reason, staggered by the reflections thus

forced upon it, finds it necessary to moderate its confidence in

such pretensions and to listen to the advice of criticism. But we

cannot stop at these doubts, much less regard the conviction of our

ignorance, not only as a cure for the conceit natural to dogmatism,

but as the settlement of the disputes in which reason is involved with

itself. On the contrary, scepticism is merely a means of awakening

reason from its dogmatic dreams and exciting it to a more careful

investigation into its own powers and pretensions. But, as

scepticism appears to be the shortest road to a permanent peace in the

domain of philosophy, and as it is the track pursued by the many who

aim at giving a philosophical colouring to their contemptuous

dislike of all inquiries of this kind, I think it necessary to present

to my readers this mode of thought in its true light.



     Scepticism not a Permanent State for Human Reason.



  The consciousness of ignorance- unless this ignorance is

recognized to be absolutely necessary ought, instead of forming the

conclusion of my inquiries, to be the strongest motive to the

pursuit of them. All ignorance is either ignorance of things or of the

limits of knowledge. If my ignorance is accidental and not

necessary, it must incite me, in the first case, to a dogmatical

inquiry regarding the objects of which I am ignorant; in the second,

to a critical investigation into the bounds of all possible knowledge.

But that my ignorance is absolutely necessary and unavoidable, and

that it consequently absolves from the duty of all further

investigation, is a fact which cannot be made out upon empirical

grounds- from observation- but upon critical grounds alone, that is,

by a thoroughgoing investigation into the primary sources of

cognition. It follows that the determination of the bounds of reason

can be made only on a priori grounds; while the empirical limitation

of reason, which is merely an indeterminate cognition of an

ignorance that can never be completely removed, can take place only

a posteriori. In other words, our empirical knowledge is limited by

that which yet remains for us to know. The former cognition of our

ignorance, which is possible only on a rational basis, is a science;

the latter is merely a perception, and we cannot say how far the

inferences drawn from it may extend. If I regard the earth, as it

really appears to my senses, as a flat surface, I am ignorant how

far this surface extends. But experience teaches me that, how far

soever I go, I always see before me a space in which I can proceed

farther; and thus I know the limits- merely visual- of my actual

knowledge of the earth, although I am ignorant of the limits of the

earth itself. But if I have got so far as to know that the earth is

a sphere, and that its surface is spherical, I can cognize a priori

and determine upon principles, from my knowledge of a small part of

this surface- say to the extent of a degree- the diameter and

circumference of the earth; and although I am ignorant of the

objects which this surface contains, I have a perfect knowledge of its

limits and extent.

  The sum of all the possible objects of our cognition seems to us

to be a level surface, with an apparent horizon- that which forms

the limit of its extent, and which has been termed by us the idea of

unconditioned totality. To reach this limit by empirical means is

impossible, and all attempts to determine it a priori according to a

principle, are alike in vain. But all the questions raised by pure

reason relate to that which lies beyond this horizon, or, at least, in

its boundary line.

  The celebrated David Hume was one of those geographers of human

reason who believe that they have given a sufficient answer to all

such questions by declaring them to lie beyond the horizon of our

knowledge- a horizon which, however, Hume was unable to determine. His

attention especially was directed to the principle of causality; and

he remarked with perfect justice that the truth of this principle, and

even the objective validity of the conception of a cause, was not

commonly based upon clear insight, that is, upon a priori cognition.

Hence he concluded that this law does not derive its authority from

its universality and necessity, but merely from its general

applicability in the course of experience, and a kind of subjective

necessity thence arising, which he termed habit. From the inability of

reason to establish this principle as a necessary law for the

acquisition of all experience, he inferred the nullity of all the

attempts of reason to pass the region of the empirical.

  This procedure of subjecting the facta of reason to examination,

and, if necessary, to disapproval, may be termed the censura of

reason. This censura must inevitably lead us to doubts regarding all

transcendent employment of principles. But this is only the second

step in our inquiry. The first step in regard to the subjects of

pure reason, and which marks the infancy of that faculty, is that of

dogmatism. The second, which we have just mentioned, is that of

scepticism, and it gives evidence that our judgement has been improved

by experience. But a third step is necessary- indicative of the

maturity and manhood of the judgement, which now lays a firm

foundation upon universal and necessary principles. This is the period

of criticism, in which we do not examine the facta of reason, but

reason itself, in the whole extent of its powers, and in regard to its

capability of a priori cognition; and thus we determine not merely the

empirical and ever-shifting bounds of our knowledge, but its necessary

and eternal limits. We demonstrate from indubitable principles, not

merely our ignorance in respect to this or that subject, but in regard

to all possible questions of a certain class. Thus scepticism is a

resting place for reason, in which it may reflect on its dogmatical

wanderings and gain some knowledge of the region in which it happens

to be, that it may pursue its way with greater certainty; but it

cannot be its permanent dwelling-place. It must take up its abode only

in the region of complete certitude, whether this relates to the

cognition of objects themselves, or to the limits which bound all

our cognition.

  Reason is not to be considered as an indefinitely extended plane, of

the bounds of which we have only a general knowledge; it ought

rather to be compared to a sphere, the radius of which may be found

from the curvature of its surface- that is, the nature of a priori

synthetical propositions- and, consequently, its circumference and

extent. Beyond the sphere of experience there are no objects which

it can cognize; nay, even questions regarding such supposititious

objects relate only to the subjective principles of a complete

determination of the relations which exist between the

understanding-conceptions which lie within this sphere.

  We are actually in possession of a priori synthetical cognitions, as

is proved by the existence of the principles of the understanding,

which anticipate experience. If any one cannot comprehend the

possibility of these principles, he may have some reason to doubt

whether they are really a priori; but he cannot on this account

declare them to be impossible, and affirm the nullity of the steps

which reason may have taken under their guidance. He can only say:

If we perceived their origin and their authenticity, we should be able

to determine the extent and limits of reason; but, till we can do

this, all propositions regarding the latter are mere random

assertions. In this view, the doubt respecting all dogmatical

philosophy, which proceeds without the guidance of criticism, is

well grounded; but we cannot therefore deny to reason the ability to

construct a sound philosophy, when the way has been prepared by a

thorough critical investigation. All the conceptions produced, and all

the questions raised, by pure reason, do not lie in the sphere of

experience, but in that of reason itself, and hence they must be

solved, and shown to be either valid or inadmissible, by that faculty.

We have no right to decline the solution of such problems, on the

ground that the solution can be discovered only from the nature of

things, and under pretence of the limitation of human faculties, for

reason is the sole creator of all these ideas, and is therefore

bound either to establish their validity or to expose their illusory

nature.

  The polemic of scepticism is properly directed against the

dogmatist, who erects a system of philosophy without having examined

the fundamental objective principles on which it is based, for the

purpose of evidencing the futility of his designs, and thus bringing

him to a knowledge of his own powers. But, in itself, scepticism

does not give us any certain information in regard to the bounds of

our knowledge. All unsuccessful dogmatical attempts of reason are

facia, which it is always useful to submit to the censure of the

sceptic. But this cannot help us to any decision regarding the

expectations which reason cherishes of better success in future

endeavours; the investigations of scepticism cannot, therefore, settle

the dispute regarding the rights and powers of human reason.

  Hume is perhaps the ablest and most ingenious of all sceptical

philosophers, and his writings have, undoubtedly, exerted the most

powerful influence in awakening reason to a thorough investigation

into its own powers. It will, therefore, well repay our labours to

consider for a little the course of reasoning which he followed and

the errors into which he strayed, although setting out on the path

of truth and certitude.

  Hume was probably aware, although he never clearly developed the

notion, that we proceed in judgements of a certain class beyond our

conception if the object. I have termed this kind of judgement

synthetical. As regard the manner in which I pass beyond my conception

by the aid of experience, no doubts can be entertained. Experience

is itself a synthesis of perceptions; and it employs perceptions to

increment the conception, which I obtain by means of another

perception. But we feel persuaded that we are able to proceed beyond a

conception, and to extend our cognition a priori. We attempt this in

two ways- either, through the pure understanding, in relation to

that which may become an object of experience, or, through pure

reason, in relation to such properties of things, or of the

existence of things, as can never be presented in any experience. This

sceptical philosopher did not distinguish these two kinds of

judgements, as he ought to have done, but regarded this augmentation

of conceptions, and, if we may so express ourselves, the spontaneous

generation of understanding and reason, independently of the

impregnation of experience, as altogether impossible. The so-called

a priori principles of these faculties he consequently held to be

invalid and imaginary, and regarded them as nothing but subjective

habits of thought originating in experience, and therefore purely

empirical and contingent rules, to which we attribute a spurious

necessity and universality. In support of this strange assertion, he

referred us to the generally acknowledged principle of the relation

between cause and effect. No faculty of the mind can conduct us from

the conception of a thing to the existence of something else; and

hence he believed he could infer that, without experience, we

possess no source from which we can augment a conception, and no

ground sufficient to justify us in framing a judgement that is to

extend our cognition a priori. That the light of the sun, which shines

upon a piece of wax, at the same time melts it, while it hardens clay,

no power of the understanding could infer from the conceptions which

we previously possessed of these substances; much less is there any

a priori law that could conduct us to such a conclusion, which

experience alone can certify. On the other hand, we have seen in our

discussion of transcendental logic, that, although we can never

proceed immediately beyond the content of the conception which is

given us, we can always cognize completely a priori- in relation,

however, to a third term, namely, possible experience- the law of

its connection with other things. For example, if I observe that a

piece of wax melts, I can cognize a priori that there must have been

something (the sun's heat) preceding, which this law; although,

without the aid of experience, I could not cognize a priori and in a

determinate manner either the cause from the effect, or the effect

from the cause. Hume was, therefore, wrong in inferring, from the

contingency of the determination according to law, the contingency

of the law itself; and the passing beyond the conception of a thing to

possible experience (which is an a priori proceeding, constituting the

objective reality of the conception), he confounded with our synthesis

of objects in actual experience, which is always, of course,

empirical. Thus, too, he regarded the principle of affinity, which has

its seat in the understanding and indicates a necessary connection, as

a mere rule of association, lying in the imitative faculty of

imagination, which can present only contingent, and not objective

connections.

  The sceptical errors of this remarkably acute thinker arose

principally from a defect, which was common to him with the

dogmatists, namely, that he had never made a systematic review of

all the different kinds of a priori synthesis performed by the

understanding. Had he done so, he would have found, to take one

example among many, that the principle of permanence was of this

character, and that it, as well as the principle of causality,

anticipates experience. In this way he might have been able to

describe the determinate limits of the a priori operations of

understanding and reason. But he merely declared the understanding

to be limited, instead of showing what its limits were; he created a

general mistrust in the power of our faculties, without giving us

any determinate knowledge of the bounds of our necessary and

unavoidable ignorance; he examined and condemned some of the

principles of the understanding, without investigating all its

powers with the completeness necessary to criticism. He denies, with

truth, certain powers to the understanding, but he goes further, and

declares it to be utterly inadequate to the a priori extension of

knowledge, although he has not fully examined all the powers which

reside in the faculty; and thus the fate which always overtakes

scepticism meets him too. That is to say, his own declarations are

doubted, for his objections were based upon facta, which are

contingent, and not upon principles, which can alone demonstrate the

necessary invalidity of all dogmatical assertions.

  As Hume makes no distinction between the well-grounded claims of the

understanding and the dialectical pretensions of reason, against

which, however, his attacks are mainly directed, reason does not

feel itself shut out from all attempts at the extension of a priori

cognition, and hence it refuses, in spite of a few checks in this or

that quarter, to relinquish such efforts. For one naturally arms

oneself to resist an attack, and becomes more obstinate in the resolve

to establish the claims he has advanced. But a complete review of

the powers of reason, and the conviction thence arising that we are in

possession of a limited field of action, while we must admit the

vanity of higher claims, puts an end to all doubt and dispute, and

induces reason to rest satisfied with the undisturbed possession of

its limited domain.

  To the uncritical dogmatist, who has not surveyed the sphere of

his understanding, nor determined, in accordance with principles,

the limits of possible cognition, who, consequently, is ignorant of

his own powers, and believes he will discover them by the attempts

he makes in the field of cognition, these attacks of scepticism are

not only dangerous, but destructive. For if there is one proposition

in his chain of reasoning which be he cannot prove, or the fallacy

in which be cannot evolve in accordance with a principle, suspicion

falls on all his statements, however plausible they may appear.

  And thus scepticism, the bane of dogmatical philosophy, conducts

us to a sound investigation into the understanding and the reason.

When we are thus far advanced, we need fear no further

attacks; for the limits of our domain are clearly marked out, and we

can make no claims nor become involved in any disputes regarding the

region that lies beyond these limits. Thus the sceptical procedure

in philosophy does not present any solution of the problems of reason,

but it forms an excellent exercise for its powers, awakening its

circumspection, and indicating the means whereby it may most fully

establish its claims to its legitimate possessions.



    SECTION III. The Discipline of Pure Reason in Hypothesis.



  This critique of reason has now taught us that all its efforts to

extend the bounds of knowledge, by means of pure speculation, are

utterly fruitless. So much the wider field, it may appear, lies open

to hypothesis; as, where we cannot know with certainty, we are at

liberty to make guesses and to form suppositions.

  Imagination may be allowed, under the strict surveillance of reason,

to invent suppositions; but, these must be based on something that

is perfectly certain- and that is the possibility of the object. If we

are well assured upon this point, it is allowable to have recourse

to supposition in regard to the reality of the object; but this

supposition must, unless it is utterly groundless, be connected, as

its ground of explanation, with that which is really given and

absolutely certain. Such a supposition is termed a hypothesis.

  It is beyond our power to form the least conception a priori of

the possibility of dynamical connection in phenomena; and the category

of the pure understanding will not enable us to ex. cogitate any

such connection, but merely helps us to understand it, when we meet

with it in experience. For this reason we cannot, in accordance with

the categories, imagine or invent any object or any property of an

object not given, or that may not be given in experience, and employ

it in a hypothesis; otherwise, we should be basing our chain of

reasoning upon mere chimerical fancies, and not upon conceptions of

things. Thus, we have no right to assume the existence of new

powers, not existing in nature- for example, an understanding with a

non-sensuous intuition, a force of attraction without contact, or some

new kind of substances occupying space, and yet without the property

of impenetrability- and, consequently, we cannot assume that there

is any other kind of community among substances than that observable

in experience, any kind of presence than that in space, or any kind of

duration than that in time. In one word, the conditions of possible

experience are for reason the only conditions of the possibility of

things; reason cannot venture to form, independently of these

conditions, any conceptions of things, because such conceptions,

although not self-contradictory, are without object and without

application.

  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 a 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 a 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 a 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 be 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 a

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, a 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, a

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 a 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 a 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 a 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.

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This World Wide Web document is a personal research project motivated by the following claim: "Truth is the object of Knowledge of whatever kind; and when we inquire what is meant by Truth, I suppose it is right to answer that Truth means facts and their relations, which stand towards each other pretty much as subjects and predicates in logic. All that exists, as contemplated by the human mind, forms one large system or complex fact, and this of course resolves itself into an indefinite number of particular facts, which, as being portions of a whole, have countless relations of every kind, one towards another." (The Idea of a University, John Henry Newman, 1801-1890)

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