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In both, the pure or priori element must be treated first, and must be carefully distinguished from that which supplied from other sources. Any other method can only lead to irremediable confusion.
Mathematics and Physics are the two theoretical sciences which have to determine their objects a priori. The former purely priori, the latter partially so, but also de
pendent on other sources of cognition.
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In the earliest times of which history affords us any record, mathematics had already entered on the sure course of science, among that wonderful nation, the Greeks. Still it is not to be supposed that it was as easy for this science to strike into, or rather to construct for itself, that royal road, as it was for logic, in which reason has only to deal with itself. On the contrary, I believe that it must have remained long -- chiefly among the Egyptians--in the stage of blind groping after its true aims and destination, and that it was revolutionised by the happy idea of one man, who struck out and determined for all time the path which this science must follow, and which admits of an indefinite advancement. The history of this intellectual revolution--much more important in its results than the discovery of the passage round the celebrated Cape of Good Hope -- and of its author, has not been preserved. But Diogenes Laertius, in naming tne supposed discoverer of some of the simplest elements of geometrical demonstration --ele ments which, according to the ordinary opinion, do not even require to be proved -- makes it apparent that the change in troduced by the first indication of this new path, must have seemed of the utmost importance to the mathematicians of that nge, and it has thus been secured against the chance of ob livion. A new light must have flashed on the mind of the first man (Thales, or whatever may have been his name) who demonstrated the properties of the isosceles triangle. For he found that it was not sufficient to meditate on the figure, as it lay before his eyes, or the conception of as existed in his mind, and thus endeavour to get at the know ledge of its properties, but that was necessary to produce these properties, as were, positive a priori construction and that, in order to arrive with certainty at priori cognition, he must not attribute to the object any other properties than those which necessarily followed from that which he had him self, in accordance with his conception, placed in the object.
? much longer period elapsed before Physics entered on the highway of science. For only about a century ami a- half since the wise Bacon gave new direction to physical studies, or rather --as others were already on the right track -- in'parted fresh vigour to the pursuit of this new direction. Here, too, as in the case of mathematics, we find evidence
rapid intellectual revolution. --In the remarks which follow shall confine myself to the empirical side of natural science.
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When Galilei experimented with balls of a definite weight on the inclined plane, when ToBRiOELLr caused the air to sustain a weight which he had calculated beforehand to be equal to that of a definite column of water, or when Stahl, at a later period, converted metals into lime, and reconverted lime into metal, by the addition and subtraction of certaiu elements ;* a light broke upon all natural philosophers. They learned that reason only perceives that which it pro duces after its own design ; that it must not be content to follow, as it were, in the leading-strings of nature, but must proceed in advance with principles of judgment according to unvarying laws, and compel nature to reply to its questions. For accidental observations, made ac cording to no preconceived plan, cannot be united under a necessary law. But it is this that reason seeks for and requires. It is only the principles of reason which can give to concordant phenomena the validity of laws, and it is only when experiment is directed by these rational principles, that it can have any real utility. Reason must approach nature with the view, indeed, of receiving information from not, however, in the character of pupil, who listens to all that his master chooses to tell him, but in that of judge, who compels the witnesses to reply to those questions which he himself thinks fit to propose. To this single idea must the revolution be ascribed, by which, after groping in the dark for so many centuries, natural science was at length conducted into the path of certain progress.
We come now to metaphysics, purely speculative science, which occupies completely isolated position, and entirely independent of the teachings of experience. deals with mere conceptions --not, like mathematics, with conceptions applied to intuition --and in reason the pupil of itself alone. the oldest of the sciences, and would still survive, even all the rest were swallowed up in the abyss of an all- destroying barbarism. But has not yet had the good for tune to attain to the sure scientific method. This will be ap parent, we apply the tests which we proposed at the outset.
We find that reason perpetually comes to stand, when attempts to gain a priori the perception even of those lav
do not here follow with exactness the history of the experimental awtbod, of which, i"leed, the first c[n are iinuKed in some obscurity.
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which the most common experience confirms. We find i< compelled to retrace its steps in innumerable instances, and to abandon the path on which it had entered, because this does not lead to the desired result. We find, too, that those who are engaged in metaphysical pursuits are far from being alilc to agree among themselves, but that, on the contrary, this science appears to furnish an arena specially adapted for the display of skill or the exercise of strength in mock-contests -- a field in which no combatant ever yet succeeded in gaining an inch of ground, ia which, at least, no victory was ever yet crowned with permanent possession.
This leads us to enquire why it is that, in metaphysics, the sure path of science has not hitherto been found. Shall we suppose that it is impossible to discover it ? Why then should nature have visited our reason with restless aspirations after
as were one of our weightiest concerns Nay, more, how little cause should we have to place confidence in our reason,
abandons us in matter about which, most of all, we desire to know the truth -- and not only so, but even allures us
to the pursuit of vain phantoms, only to betray us in the end Or, the path has only hitherto been missed, what indications
do we possess to guide us in renewed investigation, and to
enable us to hope for greater success than has fallen to the lot
of our predecessors
appears to me that the examples of mathematics and
natural philosophy, which, as we have seen, were brought into their present condition by sudden revolution, are suffi ciently remarkable to fix our attention on the essential circum stances of the change which has proved so advantageous to them, and to induce us to make the experiment of imitating them, so far as the analogy which, as rational sciences, they bear to metaphysics may permit. has hitherto been as sumed that our cognition must conform to the objects but all attempts to ascertain anything about these objects priori, by means of conceptions, and thus to extend the range of our knowledge, have been rendered abortive this assumption. Let us then make the experiment whether we may not be more successful in metaphysics, we assume that the objects must conform to our cognition. This appears, at all events, to ac cord better with the possibility of our gaining the end we have in viewi that to say, of arriving at the cognKiou ot
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objects a }inon, of determining something with respect to these objects, before they are given to os. We here propose to do just what Cofernicus did in attempting to explain the celestial movements. When he found that he could make no progress by assuming that all the heavenly bodies revolved round the spectator, he reversed the process, and tried the experiment of assuming that the spectator revolved, while the stars remained at rest. We may make the same experiment with regard to the intuition of objects. If the intuition must conform to the nature of the objects, I do not see how we can know anything of them a priori. If, on the other hand, the object conforms to the nature of our faculty of intuition, I can then easily conceive the possibility of such an a priori knowledge. Now ns I cannot rest in the mere intuitions, but--if they are to be come cognitions -- must refer them, ns representations, to some thing, as object, and must determine the latter by means of t lie former, here again there are two courses open to me.
Either, first, I may assume that the conceptions, by which I effect this determination, conform to the object --and in this case I am reduced to the same perplexity as before ; or secondly,
I inny assume that the objects, or, which is the same thing, that experience, in which alone as given objects, they are cog nized, conform to my conceptions --and then I am at no loss how to proceed. For experience itself is a modt of cognition which requires understanding. Before objects are given to me, that a priori, must presuppose in myself laws of the understanding which are expressed in conceptions a priori. To these conceptions, then, all the objects of experi ence must necessarily conform. Now there are objects which reason thinks, and that necessarily, but which cannot be given
experience, or, at least, cannot be given so as reason thinks them. The attempt to think these objects will hereafter furnish an excellent test of the new method of thought which we have adopted, and which based on the principle that we only cognize in things priori that which we ourselves place 111 them. *
This method, accordingly, which we have borrowed from the natural ohilosopher, conniats in seeking for the elements of pure reason in that which admin of confirmation or refutation by experiment. Now the proposition! of pure reason, especially when they transcend the limit* of possible experience, do not admit of our making any experiment with their nbjectt, as in natural science Hence, with regard to those conctptvtm
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This attempt succeeds as well as we could desire, and pro* muses to metaphysics, in its first part -- that where occupied with conceptions priori, of which the correspond ing objects may be given in experience --the certain course of science. For this new method we are enabled perfectly to explain the possibility of priori cognition, and, what more, to demonstrate satisfactorily the laws which lie prion at the foundation of nature, as the sum of the objects of ex perience --neither of which was possible according to the pro cedure hitherto followed. But from this deduction of the faculty of priori cognition in the first part of Metaphysics, we derive surprising result, and one which, to all appearance, militates against the great end of Metaphysics, as treated in the second part. For we come to the conclusion that our faculty of cognition unable to transcend the limits of pos sible experience and yet this precisely the most essential object of this science. The estimate of our rational cognition
priori at which we arrive that has only to do with phse- nomena, and that things in themselves, while possessing real existence, lie beyond its sphere. Here we are enabled to put the justice of this estimate to the test. For that which of necessity impels us to transcend the limits of experience and of all phsenomena, the unconditioned, which reason absolutely requires in things as they are in themselves, in order to com plete the series of conditions. Now, appears that when, on the one hand, we assume that our cognition conforms to its objects as things in themselves, the unconditioned cannot be thought without contradiction, and that when, on the other hand, we assume that our representation of things as they are given to us, does not conform to these things as they are in themselves, but that these objects, as phenomena, conform to our mode of representation, the contradiction disappears we
and prinripiet which we assume priori, our only course will lie to view them fium two different sides. We must regard one and the same con ception, on the one hand, in relation to experience as an object of the senses and of the understanding, on the other hand, in relation to reason, isolated and transcending the limits of experience, as an object of mere thought. Now we find that, when we regard things from this double point of view, the result in harmony with the principle of pure reason, but that, when we regard them from single point of view, reason involved seif-contrjdiction, then the experiment will esuMi>li it. e correctness of this distinction
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XXD
iliall then be convinced of the truth of that which we bcgnr.
by assuming for the sake of experiment ; we may look upon it as established that the unconditioned does not lie in thing* ns we know them, or as they are given to us, but in things hs they are in themselves, beyond the range of our cognition. *
But, after we have thus denied the power of speculative
reason to make any progress in the sphere of the supersensi ble, it still remains for our consideration whether data do not exist in practical cognition, which may enable us to determine the transcendent conception of the unconditioned, to rise beyond the limits of all possible experience from a practical
point of view, and thus to satisfy the great ends of metaphy sics. Speculative reason has thus, at least, made room for such an extension of our knowledge ; and, if it must leave this space vacant, still it does not rob us of the liberty to fill it up, if we can, by means of practical data--nay, it even challenges us to make the attempt. f
This attempt to introduce a complete revolution in the pro cedure of metaphysics, after the example of the Geometri cians and Natural Philosophers, constitutes the aim of the Critique of Pure Speculative Reason. It is a treatise on the method to be followed, not a system of the science itself. But, at the same time, it marks out and defines both the
* This experiment of pure reason hu a great similarity to tbat of tlie Chemtitt, which they term the experiment of reduction, or, more usualh , the synthetic process. The analyiu of the metaphysician separates pure cognition a priori into two heterogeneous elements, viz. , the cognition of things as phenomena, and of things in themselves. Dialectic combines these again into harmony with the necessary rational idea of the uncon ditioned, and finds that this harmony never results except through the above distinction, which therefore, concluded to be just.
So the central laws of the movements of the heavenly bodies es tablished the truth of that which Copernicus, at first, assumed only as hypothesis, and, at the same time, brought to light that invisible force
Newtonian attraction) which holds tbe universe together. The latter would have remained for ever undiscovered, Copernicus had not ven tured on the experiment -- contrary to the senses, but still just-- of looking for the observed movements not in the heavenly bodies, but in the spec tator. In tbia Preface treat the new metaphysical method as hypothesis with the vvw of rendering apparent the first attempts at such change of method, which are always hypothetical. But in the Critique itself will be demonstrated, not hypothetically, but apodeictically, from the nature our representations of space and time, and from the elementary concep tions of the understanding.
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external boundaries and the internal structure of this Science. For pure speculative reason has this peculiarity, that, in choosing the various objects of thought, it is able to define the limits of its own faculties, and even to give a complete enu meration of the possible modes of proposing problems to itself, and thus to sketch out the entire system of metaphysics. For, on the one hand, in cognition a priori, nothing must be at tributed to the objects but what the thinking subject derives from itself; and, on the other hand, reason is, in regard to the principles of cognition, a perfectly distinct, independent unity, in which, as in an organised body, every member exists for the sake of the others, and all for the sake of each, so that no principle can be viewed, with safety, in one relationship, unless it at the same time, viewed in relation to the totnl nse of pure reason. Hence, too, metaphysics has this singular advantage --an advantage which falls to the lot of no other science which has to do with objects--that, once con ducted into the sure path of science, by means of this criti cism, can then take in the whole sphere of its cognitions, and can thus complete its work, and leave for the use of posterity, as capital which can never receive fresh acces sions. For metaphysics has to deal only with principles and with the limitations of its own employment as determined these principles. To this perfection therefore, bound, as the fundamental science, to attain, and to the maxim may
justly be applied --
Nii actum reputans, quid anperestct agendum.
But, will be asked, what kind of treasure this that we propose to bequeath to posterity What the real value of this system of metaphysics, purified by criticism, and thereby reduced to permanent condition cursory view of the present work will lead to the supposition that its use merely negative, that only serves to warn us against venturing, with speculative reason, beyond the limits of experience. This
in fact, its primary use. But this, at once, assumes positive value, when we observe that the principles with which specu lative reason endeavours to transcend its limits, lead inevitably, not to the extension, but to the contraction of the use of reason, inasmuch as they threaten to extend the limits of sen sibility, which their proper sphere, over the entire realm M
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thought, and thus to supplant the pure (practical) use of reasou. So far, then, as this criticism is occupied in confining speculative reason within its proper bounds, it is only negative ; hut, inasmuch as it thereby, at the same time, removes an obstacle which impedes and even threatens to destroy the use
of practical reason, it possesses a positive and very important value. In order to admit this, we have only to be convinced that there is an absolutely necessary use of pure reason -- the moral use --in which it inevitably transcends the limits of sensibility, without the aid of speculation, requiring only to be insured against the effects of a speculation which would involve it in contradiction with itself. To deny the positive advantage of the service which this criticism renders us, would be as absurd as to maintain that the system of police is productive of no positive benefit, since its main business is to prevent the violence which citizen has to appre hend from citizen, that so each may pursue his vocation in peace and security. That space and time are only forms of sensible intuition, and hence are only conditions of the existence of things as phenomena ; that, moreover, we have no conceptions of the understanding, and, consequently, no elements for the cognition of things, except in so far aa a cor responding intuition can be given to these conceptions ; that, accordingly, we can have no cognition of an object, as a thing in itself, but only as an object of sensible intuition, that as phenomenon, -- all this proved in the Analytical part of the Critique and from this the limitation of all possible specula tive cognition to the mere objects of experience, follows as necessary result. At the same time, must be carefully borne
mind that, while we surrender the power of cognizing, we still reserve the power of. thinking objects, as tilings in them selves. * For, otherwise, we should require to affirm the exist-
In order to cognize an object, must be able to prove its possibility, either from its reality as attested experience, or a priori, by means of reason. But can think what please, provided only do not contradict myself that provided my conception possible thought, though may be unable to answer for the existence of a corresponding object in the sum of possibilities. But something more required before can attribute to such conception objective validity, that is real possibility-- the other possibility being merely logical. We are not, however, confined to . theoretical sources of cognition for the means of satisfying this addi tional requirement, but mav derive them from practical source?
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ence of an appearance, without something that appears-- which would be absurd. Now let us suppose, for a moment, that we had not undertaken this criticism, and, accordingly, had not drawn the necessary distinction between things, as objects of experience, and things, as they are in themselves. The principle of causality, and, by consequence, the mecha nism of nature as determined by causality, would then have absolute validity in relation to all things as efficient causes. 1 should then be unable to assert, with regard to one and the same being, t. g. , the human soul, that its will is free, and yet, a', the same time, subject to natural necessity, that is. not free, without falling into a palpable contradiction, for in both pro positions I should take the soul in the same signification, us a thing in general, as a thing in itself -- as, without previous criticism, I could not but take it. Suppose now, on the other hand, that we have undertaken this criticism, and have learui that an object may be taken in two senses, first, as a pheno menon, secondly, as a thing in itself ; and that, according to the deduction of the conceptions of the understanding, the princi ple of causality has reference only to things in the first sense. VVe then see how it does not involve any contradiction to assert, on the one hand, that the will, in the phenomenal sphere --in visible action, is necessarily obedient to the law of nature, and, in so far not free; and, on the other hand, that, as belonging tc a thing in itself, it is not subject to that law, and, accordingly, is/ree. Now, it is true that I cannot, by means of specula tive reason, and still less by empirical observation, cognize my ? oul as a thing in itself, and consequently, cannot cognize liberty as the property of a being to which I ascribe effects in the world of sense. For, to do so, I must cognize this being as existing, and yet not in time, which -- since I cannot sup port my conception by any intuition --is impossible. At the same time, while I cannot cognize, I can quite well think freedom, that is to say, my representation of it involves nt least no contradiction, if we bear in mind the critical distinc tion of the two modes of representation (the sensible and the intellectual) and the consequent limitation of the conceptions of the pure understanding, and of the principles which flow from them. Suppose now that morality necessarily presup posed liberty, in the strictest sense, as a property of our will ; suppose tliai reason contained certain practical, original priu
? ? ? ? PHFTACE TO THE 8ECOITD EDITION XIXV
ciples a priori, which were absolutely impossible without this presupposition ; and suppose, at the sam<" time, that specula
tive reason had proved that liberty was incapable of being
thought at all. It would then follow that the moral presup
position must give way to the speculative affirmation, the opposite of which involves an obvious contradiction, and that liberty and, with morality must yield to the mechanism nature for the negation of morality involves no contradiction, except on the presupposition of liberty. Now morality does not require the speculative cognition of liberty enough that can think that its conception involves no contradic tion, that does not interfere with the mechanism of nature. But even this requirement we could not satisfy, we had not learnt the two-fold sense which things may be taken and
ouly in this way that the doctrine of morality and the doctrine of nature are confined within their proper limits. For this result, then, we are indebted to criticism which warns us of our unavoidable ignorance with regard to things . n themselves, and establishes the necessary limitation of oui theoretical cognition to mere phenomena.
The positive value of the critical principles of pure reason . n relation to the conception of God and of the simple nature of the soul, admits of similar exemplification but on this point shall not dwell. cannot even make the assumption --as the practical interests of morality require--of God, Free dom, and Immortality, do not deprive speculative reason of its pretensions to transcendent insight. For to arrive at these, must make use of principles which, in fact, extend only to the objects of possible experience, and which cannot be applied to objacts beyond this sphere without converting them into phenomena, and thus rendering the practical exten sion of pure reason impossible. must, therefore, abolish knowledge, to make room for belief. The dogmatism of metaphysics, that is, the presumption that possible to ad vance in metaphysics without previous criticism, the true source of the unbelief (always dogmatic) which militates against morality.
Thus, while may be no very difficult task to bequeath legacy to posterity, in the shape of system of metaphysics constructed in accordance with the Critique of Pure Reason, still the value of such bequest not to be depreciated.
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will render an important service to reason, by substituting the certainty of scientific method for that random groping after results without the guidance of principles, which has hit her U characterised the pursuit of metaphysical studies. It will render an important service to the inquiring mind of youth, by leading the student to apply his powers to the cultivation of genuine science, instead of wasting them, as at present, on speculations which can never lead to any result, or on the idle attempt to invent new ideas and opinions. But, above all, it will confer an inestimable benefit on morality and religion, by showing that all the objections urged against them may be silenced for ever by the Socratic method, that is to say, by proving the ignorance of the objector. For, as the world has never been, and, no doubt, never will be, without a system of metaphysics of one kind or another, it is the highest and weightiest concern of philosophy to render it powerless for harm, by closing up the sources of error.
This important change in the field of the sciences, this loss of its fancied possessions, to which speculative reason must submit, does not prove in any way detrimental to the general interests of humanity. The advantages which the world has derived from the teachings of pure reason, are not at all im paired. The loss falls, in its whole extent, on the monopoly of the schools, but does not in the slightest degree touch the ? '<<- teresls of mankind. I appeal to the most obstinate dogmatist, whether the proof of the continued existence of the soul after death, derived from the simplicity of its substance ; of the freedom of the will in opposition to the general mechanism of nature, drawn from the subtle but impotent distinction of sub jective and objective practical necessity ; or of the existence of God, deduced from the conception of an ens realissimum, --the contingency of the changeable, and the necessity of a prime mover, has ever been able to pass beyond the limits of the schools, to penetrate the public mind, or to exercise the slightest influence on its convictions. It must be admitted
that this has not been the case, and that, owing to the unfitness of the common understanding for such subtle speculations, it can never be expected to take place. On the contrary, it it plain that the hope of a future life arises from the feeling, which exists in the breast of every man, that the temporal it inadenuate to meet and satisfy the dcmnpda of his rnturfl.
? ? ? ? PREFACE TO THE SECOND EDITION. xxxvii
In like manner, it cannot be doubted that the clear exhibition of duties in opposition to all the claims of inclination, gives rise to the consciousness of freedom, and that the glorious order, beauty, and providential care, everywhere displayed in nature, give rise to the belief in a wise and great Author of the Universe. Such is the genesis of these general convictions of mankind, so far as they depend on rational grounds ; and this public property not only remains undisturbed, but is even raised to greater importance, by the doctrine that the schools have no right to arrogate to themselves a more profound insight into a matter of general human concernment, than that to which the great mass of men, ever held by us in the highest estimation, can without difficulty attain, and that the schools should therefore confine themselves to the elaboration of these universally comprehensible, and, from a moral point of view, amply satisfactory proofs. The change, therefore, affects only the arrogant pretensions of the schools, which would gladly retain, in their own exclusive possession, the key to the truths which they impart to the public.
Quod mecum nescit, solus vult scire videri.
At the same time it does not deprive the speculative philoso pher of his just title to be the sole depos. tor of a science which benefit* the public without its knowledge -- I meau, the Critique of Pure Reason. This can never berime popular, and, indeed, has no occasion to be so; for fne-spun argu ments in favour of useful truths, make just as little impression on the public mind as the equally subtle objections brought against these truths. On the other hand, since both inevitably force themselves on every man who rises to the height of speculation, it becomes the manifest duty of the schools to enter upon a thorough investigation of the rights of specula tive reason, and thus to prevent the scandal which metaphysical controversies are sure, sooner or later, to cause even to the masses. It is only by criticism that metaphysicians (and, as snch, theologians too) can be saved from these controversies and from the consequent perversion of their doctrines. Criti cism alone can strike a blow at the root of Materialism, Fatal
ism, Atheism, Free-thinking, Fanaticism, and Superstition, which are universally injurious -- as well as of Idealism and Scepticism, which are dangerous to the schools, but can scorcelj
? ? ? ? ixxviii PREFACE TO THE 8F. COKD EDITION.
pass over to the public. If governments think proper to in terfere with the affairs of the learned, it would be more con sistent with a wise regard for the interests of science, as well as for those of society, to favour a criticism of this kind, by which alone the labours of reason can be established on a firm basis, than to support the ridiculous despotism of the schools, which raise a loud cry of danger to the public over the de struction of cobwebs, of which the public lias never taken any notice, and the loss of which, therefore, it can never feel.
This critical science is not opposed to the dogmatic proce dure of reason iu pure cognition ; for pure cognition must n I ways be dogmatic, that is, must rest on strict demonstration from sure principles a priori -- but to dogmatism, that to (he presumption that possible to make any progress with
pure cognition, derived from (philosophical) conceptions, according to the principles which reason has long been in the habit of employing-- without first inquiring in what way and
what right reason has come into the possession of these principles. Dogmatism thus the dogmatic procedure of pure reason without previous criticism of its own powers, and in opposing this procedure, we must not be supposed to lend any countenance to that loquacious shallowness which arro gates to itself the name of popularity, nor yet to scepticism, which makes short work with the whole science of metaphy sics. On the contrary, our criticism the necessary pre paration for thoroughly scientific system of metaphysics, which must perform its task entirely a priori, to the com plete satisfaction of speculative reason, and must, therefore, lie treated, not popularly, but scholastic-ally. In carrying out the plan which the Critique prescribes, that is, in the future sys tem of metaphysics, we must have recourse to the strict method of the celebrated Wolf, the greatest of all dogmatic philoso phers. He was the first to point out the necessity of establishing fixed principles, of clearly defining our conceptions, and
our demonstrations to the most severe scrutiny, instead of rashly jumping at conclusions. The example which he set, served to awaken that spirit of profound and thorough investigation which not yet extinct in Germany. He would have been peculiarly well fitted to give truly scientific cha racter to metaphysical studies, had occurred to him to pre pare the field bv criticism of the organum, that of pure
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reason itself. That he failed to perceive the necessity of such a procedure, must be ascribed to the dogmatic mode of thought which characterized his age, and on this point the philosophers of his time, as well as of all previous times, have nothing to reproach each other with. Those who reject at once the method of Wolf, and of the Critique of Pure Reason, can haze no. other aim but to shake off the fetters of science, to change labour into sport, certainty into opinion, and philosophy into philodoxy.
sible, to remove the difficulties and obscurity, which, without
fault of mine perhaps, have given rise to many misconceptions even among acute thinkers. In the propositions themselves, and in the demonstrations by which they are supported, a? well as in the form and the entire plan of the work, I have found nothing to alter ; which must be attributed partly to the long examination to which I had subjected the whole before offering it to the public, and partly to the nature of the case. For pure speculative reason is an organic structure in which there is nothing isolated or independent, but every single part is essential to all the rest ; and hence, the slightest imperfection, whether defect or positive error, could not fail to betray itself in use. I venture, further to hope, that this system will maintain the same unalterable character for the future. I am led to entertain this confidence, not by vanity, but by the evidence which the equality of the result affords, when we proceed, first, from the simplest elements up to the complete whole of pure reason, and then, backwards from the whole to each individual part. We find that the attempt to make the
slightest alteration, in any part, leads inevitably to contradic tions, not merely in this system, but in human reason itself. At the same time, there is still much room for improvement in the exposition of the doctrines contained in this work. In the present edition, I have endeavoured to remove misappre hensions of the esthetical part, especially with regard to the conception of Time ; to clear away the obscurity which has been found in the deduction of the conceptions of the under standing ; to supply the supposed want oT sufficient evidence in the demonstration of the principles of lie pure understand, ing ; and, lastly, to obviate the misunderstanding of the paralo gisms which immediately precede the Rational Psychology.
In this second edition, I have endeavoured, as far as pos
? ? ? ? XI fin: face ro toe second editi i*.
Beyond this poiut--the end of the second Maitt Division of the Transcendental Dialectic -- I hnve not extended my altera tions,* partly from want of tice, and partly because I am
* The only addition, properly so called --and that only in the method of proof--which I have made in the present edition, consists of a new refutation of psychological Idealism, and a strict demonstration -- the only one possible, as I believe-- of the objective reality of external intuition However harmless Idealism may be considered-- although in reality it is not so--in regard to the essential ends of metaphysics, it must still remain a scandal to philosophy and to the general human reason to be obliged to assume, as an article of mere belief, the existence of things external to ourselves (from which, yet, we derive the whole material of cognition even for the internal sense), and not to lie able to oppose a satisfactory proof to any one who may call it in question. As there is some obscurity of ex pression in the demonstration as it stands in the text, I propose to alter the passage in question as follows : " But this permanent cannot be an in tuition in me. For all the determining grounds of my existence which can be found in me, are representations, and, as such, do themselves re quire a permanent, distinct from them, which may determine my existence in relation to their changes, that my existence in time, wherein they change. " may, probably, be urged in opposition to this proof, that, after all, am only conscious immediately of that which in me, that
of my representation of external things, and that, consequently, must always remain uncertain whether anything corresponding to this repre sentation, does or does not exist externally to me. But am conscious, through internal experience, of my existence hi time, (consequently, also, ol the determinability of the former in the latter), and that more than the simple consciousness of my representation. in fact, the same as the
empirical consciousness of my existence, which can oidy be determined relation to something, which, while connected with my existence, ex ternal to me. This consciousness of my existence in time is, therefore, identical with the consciousness of relation to something external to me, and is, therefore, experience, not fiction, sense, not imagination, which inseparably connects the external with my intemal sense. For the ex ternal sense is, in itself, the relation of intuition to something real, ex ternal to me and the reality of this something, as opposed to the mere imagination of it, rests solely on its inseparable connection with internal experience as the condition of its possibility. with the intellectual consciousness of my existence, in the representation am, which accom panies all my judgments, and all the operations of my understanding, could, at the same time, connect determination of my existence in- tellectual intuition, then the consciousness of relation to something ex ternal to me would not be necessary. But the internal intuition in which alone my existence can he determined, though preceded by that purely intellectual consciousne itself sensible and attached to the condition of time. Hence this ermination of my existence, and consequently my internal experience itself, must depend on something permanent which is not in me, which can be. therefore, only in something external to me, to which must look upon myself as k'i laljd. Thus the eality
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not aware that any portion of the remainder bas given rise tc misconceptions among intelligent and impartial critics, whom I do not here mention with that praise which is their due, hut who will find that their suggestions have been attended to in the work itself.
In attempting to render the exposition of my views as intel
ligible as possible, I have been compelled to leave out 01 abridge various passages which were not essential to the com pleteness of the work, but which many readers might consider useful in other respects, and might be unwilling to miss. This trifling loss, which could not be avoided without swelling the book beyond due limits, may be supplied, at the pleasure of the reader, by a comparison with the first edition, and will, I hope, be more than compensated for by the greater clearness of the exposition as it now stands.
I have observed, with pleasure and thankfulness, in the pages of various reviews and treatises, that the spirit of pro found and thorough investigation is not extinct in Germany, though it may have been overborne and silenced for a time by the fashionable tone of a licence in thinking, which gives itself the airs of genius --and that the difficulties which beset the paths of Criticism have not prevented energetic and acute thinkers from making themselves masters of the science of pure reason to which these paths conduct--a science which
? the external sense is necessarily connected with that of the internal, in order to the possibility of experience in general ; that am just as certainly conscious that there are things external to me related to my sense, as am that myself exist, as determined in time. But in order to ascertain to what given intuitions objects, external to me, really correspond, in other words, what intuitions belong to the external sense and not to imagination, must have recourse, in every particular case, to those rules according to which experience in general (even internal experience) distinguished from imagination, and which are always based on the pro position that there really an external experience. --We may add the reirarlc, that the representation of something permanent in existence, not the same thing as the permanent representation for representation may be very variable and changing -- as all our representations, even
that of matter, are -- and yet refer to something permanent, which must, therefore, be distinct from all my representations and external to me, the existence of which necessarily included in thf termination of my owa
existence, and with constitutes one experien t--an experience which would not even be possible internally, were not also at the same time, in part, external. To the question How we are no more able to reply, than we are, in general, to think the stationary in time, the co -existence which with the variable, produces the conception of change.
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u not popular, but scholastic in its charac'cr, and which alone can hope for a lasting existence or possess au abiding value. To these deserving men, who so happily combine profundity of view with a talent for lucid exposition -- a talent which I myself am not conscious of possessing --I leave the task of removing any obscurity which may still adhere to the statement of my doctrines. For, in this case, the danger is not that of being refuted, but of being misunderstood. For my own part, I must henceforward abstain from controversy, although I shall carefully attend to all suggestions, whether from friends or adversaries, which may be of use in the future elaboration of the system of this Propedeutic. As, during these labours, I have advanced pretty far in years -- this month
I reach my sixty-fourth year -- it will be necessary for me to economize time, if I am to carry out my plan of elaborating the Metaphysics of Nature as well as of Morals, in confirmation
)f the correctness of the principles established in this Critique af Pure Reason, both Speculative and Practical ; and I must, therefore, leave the task of clearing up the obscurities of the present work -- inevitable, perhaps, at the outset -- as well as the defence of the whole, to those deserving men who have made my system their own. A philosophical system cannot come forward armed at all points like a mathematical treatise, and hence it may be quite possible to take objection to parti cular passages, while the organic structure of the system, con sidered as a unity, has no danger to apprehend. But few possess the ability, and still fewer the inclination, to take a comprehensive view of a new system. By confining the view to particular passages, taking these out of their connection and comparing them with one another, it is easy to pick out apparent contradictions, especially in a work written with any freedom of style. These contradictions place the work in an unfavourable light in the eyes of those who rely on the judg ment of others, but are easily reconciled by those who have mastered the idea of the whole. If a theory possesses stabi lity in itself, the action and reaction which seemed at first to threaten its existence, serve only, in the course of time, to smooth down any s\ erficial roughness or inequality, and -- if men of insight, im irtiality, and truly popular gifts, turn their attention to it -- to secure to short time, the requj-
<<ite elegance also.
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I. Or TEE DIFFERENCE BETWEEN PURE AND SMITHICI L KNOWLEDGE.
That all our knowledge begins with experience there can be no doubt. For how is it possible that the faculty of cog nition should be awakened into exercise otherwise than by means of objects which affect our senses, and partly of them<< selves produce representations, partly rouse our powers ol understanding into activity, to compare, to connect, or to se parate these, and so to convert the raw material of our sensuous impressions into a knowledge of objects, which is called ex perience? In respect of time, therefore, no knowledge cf ours is antecedent to experience, but begins with it.
But, though nll our knowledge begins with experience, it by no means follows, that all arises out of experience. For,
on the contrary, it is quite possible that our empirical know ledge is a compound of that which we receive through im pressions, and that which the faculty of cognition supplies from itself (sensuous impressions giving merely the occasion), an addition which we cannot distinguish from the original element given by sense, till long practice has made us at tentive to, and skilful in separating it. It is, therefore, a question which requires close investigation, and is not to be answered at first sight, -- whether there exists a knowledge altogether independent of experience, and even of all sensuous impressions ? Knowledge of this kind is called a priori, in contradistinction to empirical knowledge, which has its sources a posteriori, that in experience.
? But the expression, " priori," not as yet definite
enough, adequately to indicate the whole meaning of. tht question above started. For, in speaking cf knowledge wukh
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has its sources In experience, we are wont to say, that this or
that may be known ii priori, because we do not derive thia
knowledge immediately from experience, but from a general rule, which, however, we have itself borrowed from experi ence. Thus, if a man undermined his house, we say, " he might know h priori that it would have fallen ;" that he needed not to have waited for the experience that did actu ally fall. But still, priori, he could not know even this much. For, that bodies are heavy, and, consequently, that they fall when their supports are taken away, must have been known to him previously, by means of experience.
? By the term " knowledge priori," therefore, we stall in the sequel understand, not such as independent of this or that kind of experience, but such as absolutely so of all ex perience. Opposed to this empirical knowledge, or that which possible only a posteriori, that is, through experi ence. Knowledge priori either pure or impure. Pure knowledge priori that with which no empirical element mixed up. For example, the proposition, " Every change has cause," proposition priori, but impure, because change conception which can only he derived from expe rience.
II. The nuMAX intellect, even in an unfhilosofhical STATE, IS IN POSSESSION OF CERTAIN COGNITIONS PRIORI.
The question now as to criterion, by which we may
securely distinguish pure from an empirical cognition. Ex perience no doubt teaches us that this or that object con stituted in such and such manner, but not that could not possibly exist otherwise. Now, in the first place, we have
proposition which contains the idea of necessity in its very conception, judgment priori moreover, not derived from any other proposition, unless from one equally involving the idea of necessity, absolutely priori. Se condly, an empirical judgment never exhibits strict and abso lute, but only assumed and comparative universality (by in duction) therefore, the most we can say --so far as we have hitherto observed, there
rule. If, on the other hand, and absolute universality, that
no exception to this or that judgment carries with strict
admits of no possible excep
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tion, it is not derived from experience, but is valid absolutely a priori.
Empirical universality is, therefore, only an arbitrary ex tension of validity, from that which may be predicated of a proposition valid in most cases, to that which is asserted of a proposition which holds good in all ; as, for example, in the affirmation, " all bodies are heavy. '
strict universality characterizes a judgment, it necessarily indicates another peculiar source of knowledge, namely, a faculty of cognition <i priori. Necessity and strict univer sality, therefore, are infallible tests for distinguishing pure from empirical knowledge, and are inseparably connected with each other. But as in the use of these criteria the empirical limitation is sometimes more easily detected than the contingency of the judgment, or the unlimited universality which we attach to a judgment is often a more convincing proof than its necessity, it may be advisable to use the criteria separately, each being by itself infallible.
? Now, that in the sphere of human cognition, we have judgments which are necessary, and in the strictest sense universal, consequently pure ii priori, it will be an easy matter to shew. If we desire an example from the sciences,
we need only take any proposition in mathematics. If
we cast our eyes upon the commonest operations of the un
derstanding, the proposition, " every change must have a cause," will amply serve our purpose. In the latter case, indeed, the conception of a cause so plainly involves the con ception of a necessity of connexion with an effect, and of a strict universality of the law, that the very notion of a cause would entirely disappear, were we to derive like Hume, from frequent association of what happens with that which precedes, and the habit thence originating of connecting re presentations --the necessity inherent in the judgment being therefore merely subjective. Besides, without seeking for such examples of principles existing priori in cognition, we might easily shew that such principles are the indispen sable basis of the possibility of experience itself, and con sequently prove their existence priori. For whence could our experience itself acquire certainty, all the rules on which
depends were themselves empirical, and consequently for tuitous No one, therefore, can admit the validity of the use
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of sucb rules as first principles. But, for the present, we may content ourselves with having established the fact, that we do possess and exercise a faculty of pure a priori cog nition ; and, secondly, with having pointed out the proper teats of such cognition, namely, universality and necessity.
Not only in judgments, however, hut even in conceptions, is an A priori origin manifest. For example, if we take away by degrees from our conceptions of a body all that can be referred to mere sensuous experience--colour, hardness or eoftness, weight, even impenetrability -- the body will then vanish ; but the space which it occupied still remains, and this it is utterly impossible to annihilate in thought. Again, if we take away, in like manner, from our empirical conception
of any object, corporeal or incorporeal, all properties which mere experience has taught us to connect with still we cannot think away those through which we cogitate as substance, or adhering to substance, although our conception of substance more determined than that of an object. Compelled, therefore, by that necessity with which the con ception of substance forces itself upon us, we must confess that has its seat in our faculty of cognition priori.
III. PniLOSOPHY STANDS IN NEED OF A SCIENCE WHICH SHALL DETERMINE THE POSSIBILITY, PRINCIPLES, AND EXTENT OF HUMAN KNOWLEDGE PRIORI.
Of far more importance than all that has been above said, the consideration that certain of our cognitions rise com
pletely above the sphere of all possible experience, and by means of conceptions, to which there exists in the whole ex tent of experience no corresponding object, seem to extend the range of our jndgments beyond its bounds. And just in this transcendental or supersensible sphere, where experience affords us neither instruction nor guidance, lie die investi gations of Reason, which, on account of their importance, we consider far preferable to, and as having far more elevated aim than, all that the understanding can achieve within the sphere of sensuous phenomena. So high value do we set upon these investigations, that even at the risk of error, we persist in following them out, and permit neither doubt nor disregard nor indifference to restrain us from the pur suit. These unavoidable problems of mere pure reason are
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God, Freedom (of will) and Immortality. The science which, with all its preliminaries, has for its especial object the solution of these problems is named metaphysics, --a science which is at the very outset dogmatical, that con fidently takes upon itself the execution of this task without
any previous investigation of the ability or inability of reason for such an undertaking.
Now the safe ground of experience being thus abandoned, seems nevertheless natural thst we should hesitate to erect building with the cognitions we possess, without knowing whence they come, and on the strength of principles, the origin of whirh undiscovered. Instead of thus trying to build without foundation, rather to be expected that
we should long ago have put the question, how the under
can arrive at these priori cognitions, and what the extent, validity, and worth which they may possess We say, this natural enough, meaning by the word natural, that which consistent with just and reasonable way of think ing but we understand by the term, that which usually happens, nothing indeed could be mere natural and more
some evident contradiction, we hurry on undoubtingly in our course. This, however, may be avoided, we are suffi ciently cautious in the construction of our fictions, which are not the less fictions on that account.
Mathematical science affords us brilliant example, how far, independently of all experience, we may carry our priori knowledge. true that the mathematician occupies himself with objects and cognitions only in so far as they can be represented by means of intuition. But this circumstance
easily overlooked, because the said intuition can itself be given priori, and therefore hardly to be distinguished from mere pure conception. Deceived such proof of
? standing
than that this investigation should be left
comprehensible
long unattempted. For one part of our pure knowledge, the science of mathematics, has been long firmly estab lished, and thus leads us to form flattering expectations with regard to others, though these may be of quite different nature. Besides, when we get beyond the bounds of ex perience, we are of course safe from opposition in that quarter and the charm of widening the range of our know ledge so great, that unless we are brought to stand-still
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IKTBODUCTIOIT.
the power of reason, we can perceive no limits to the ex tension of our knowledge. The light dove cleaving in free flight the thin air, whose resistance it feels, might imagine that her movements would he far more free and rapid in air less space. Just in the same way did Plato, abandoning the world of sense because of the narrow limits it sets to the understanding, venture upon the wings of ideas beyond into the void space of pure intellect. He did not reflect that he made no real progress by all his efforts for he met with no resistance which might serve him for support, as were, whereon to rest, and on which he might apply his powers, in order to let the intellect acquire momentum for its progress.
indeed, the common fate of human reason in speculation, to finish the imposing edifice of thought as rapidly as possible, and then for the first time to begin to examine whether the foundation solid one or no. Arrived at this point, all sorts of excuses are sought after, in order to console us for its want of stability, or rather indeed, to enable us to dispense
altogether with so late and dangerous an investigation. But what frees us during the process of building from all appre hension or suspicion, and flatters us into the belief of its solidity, this. great part, perhaps the greatest part, of the business of our reason consists in the analyxation of the
which we already possess of objects. By this means we gain multitude of cognitions, which although really nothing more than elucidations or explanations of that which (though in confused manner) was already thought in our conceptions, are, at least in respect of their form, prized as new introspections whilst, so far as regards their matter or content, we have really made no addition to our con ceptions, but only disinvolved them. But as this process does furnish r? al priori knowledge,* which has sure progress and useful results, reason, deceived this, slips in, without being itself aware of assertions of quite different kind; in which, to given conceptions adds others, priori in deed, but entirely foreign to them, without our knowing how
arrives at these, and, indeed, without such question ever suggesting itself. shall therefore at once proceed to examine the difference between these two modes of knowledge.
Not ivnthetical. -- Tr.
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IV. Or TnE DTFFEHENCE BETWEEN ANALYTICAL AND 6TNTUETICAL JUDGMENTS.
In all judgments wherein the relation of a subject to the pre
dicate is cogitated, (I mention affirmative judgments only
here ; the application to negative will be very easy,) this rela
tion is possible in two different ways. Either the predicate
B belongs to the subject A, as somewhat which is contained
(though covertly) in the conception A ; or the predicate B
lies completely out of the conception A, although it stands in connexion with it. In the first instance, I term the judgment
analytical, in the second, synthetical. Analytical judgments
are therefore those in which the connection of the predicate with the subject is cogitated through identity ; those in which this connexion is cogitated without identity, are called synthetical judgments. The former may be called explicative, the latter augmentative* judgments ; because the former add in the predicate nothing to the conception of the subject, but only analyse it into its constituent conceptions, which were thought already in the subject, although in a con fused manner ; the latter add to our conceptions of the subject a predicate which was not contained in and which no analysis could ever have discovered therein. For example, when say, "all bodies are extended," this an analytical judgment. For need not go beyond the conception of body
order to find extension connected with but merely analyse the conception, that is, become conscious of the manifold properties which think in that conception, in order to discover this predicate in therefore an ana lytical judgment. On the other hand, when say, " all bodies are heavy," the predicate something totally different from that which think in the mere conception of
By the addition of such predicate therefore, becomes synthetical judgment.