THE CRITIQUE OF PURE REASONby Immanuel Kanttranslated by J. M. D. MeiklejohnPREFACE TO THE FIRST EDITION, 1781Human reason, in one sphere of its cognition, is called upon toconsider questions, which it cannot decline, as they are presentedby its own nature, but which it cannot answer, as they transcend everyfaculty of the mind.It falls into this difficulty without any fault of its own. Itbegins with principles, which cannot be dispensed with in the fieldof experience, and the truth and sufficiency of which are, at the sametime, insured by experience. With these principles it rises, inobedience to the laws of its own nature, to ever higher and moreremote conditions. But it quickly discovers that, in this way, itslabours must remain ever incomplete, because new questions never ceaseto present themselves; and thus it finds itself compelled to haverecourse to principles which transcend the region of experience, whilethey are regarded by common sense without distrust. It thus falls intoconfusion and contradictions, from which it conjectures the presenceof latent errors, which, however, it is unable to discover, becausethe principles it employs, transcending the limits of experience,cannot be tested by that criterion. The arena of these endlesscontests is called Metaphysic.Time was, when she was the queen of all the sciences; and, if wetake the will for the deed, she certainly deserves, so far asregards the high importance of her object-matter, this title ofhonour. Now, it is the fashion of the time to heap contempt andscorn upon her; and the matron mourns, forlorn and forsaken, likeHecuba:    Modo maxima rerum,    Tot generis, natisque potens...    Nunc trahor exul, inops.            -- Ovid, Metamorphoses. xiiiAt first, her government, under the administration of thedogmatists, was an absolute despotism. But, as the legislativecontinued to show traces of the ancient barbaric rule, her empiregradually broke up, and intestine wars introduced the reign ofanarchy; while the sceptics, like nomadic tribes, who hate a permanenthabitation and settled mode of living, attacked from time to timethose who had organized themselves into civil communities. But theirnumber was, very happily, small; and thus they could not entirelyput a stop to the exertions of those who persisted in raising newedifices, although on no settled or uniform plan. In recent timesthe hope dawned upon us of seeing those disputes settled, and thelegitimacy of her claims established by a kind of physiology of thehuman understanding--that of the celebrated Locke. But it was foundthat--although it was affirmed that this so-called queen could notrefer her descent to any higher source than that of common experience,a circumstance which necessarily brought suspicion on her claims--asthis genealogy was incorrect, she persisted in the advancement ofher claims to sovereignty. Thus metaphysics necessarily fell back intothe antiquated and rotten constitution of dogmatism, and againbecame obnoxious to the contempt from which efforts had been made tosave it. At present, as all methods, according to the generalpersuasion, have been tried in vain, there reigns nought but wearinessand complete indifferentism--the mother of chaos and night in thescientific world, but at the same time the source of, or at leastthe prelude to, the re-creation and reinstallation of a science,when it has fallen into confusion, obscurity, and disuse from illdirected effort.For it is in reality vain to profess indifference in regard tosuch inquiries, the object of which cannot be indifferent to humanity.Besides, these pretended indifferentists, however much they may tryto disguise themselves by the assumption of a popular style and bychanges on the language of the schools, unavoidably fall intometaphysical declarations and propositions, which they profess toregard with so much contempt. At the same time, this indifference,which has arisen in the world of science, and which relates to thatkind of knowledge which we should wish to see destroyed the last, isa phenomenon that well deserves our attention and reflection. It isplainly not the effect of the levity, but of the matured judgement*of the age, which refuses to be any longer entertained with illusoryknowledge, It is, in fact, a call to reason, again to undertake themost laborious of all tasks--that of self-examination, and toestablish a tribunal, which may secure it in its well-grounded claims,while it pronounces against all baseless assumptions andpretensions, not in an arbitrary manner, but according to its owneternal and unchangeable laws. This tribunal is nothing less thanthe critical investigation of pure reason.[*Footnote: We very often hear complaints of the shallowness of thepresent age, and of the decay of profound science. But I do not thinkthat those which rest upon a secure foundation, such as mathematics,physical science, etc., in the least deserve this reproach, but thatthey rather maintain their ancient fame, and in the latter case,indeed, far surpass it. The same would be the case with the otherkinds of cognition, if their principles were but firmly established.In the absence of this security, indifference, doubt, and finally,severe criticism are rather signs of a profound habit of thought.Our age is the age of criticism, to which everything must besubjected. The sacredness of religion, and the authority oflegislation, are by many regarded as grounds of exemption from theexamination of this tribunal. But, if they on they are exempted,they become the subjects of just suspicion, and cannot lay claim tosincere respect, which reason accords only to that which has stoodthe test of a free and public examination.]I do not mean by this a criticism of books and systems, but acritical inquiry into the faculty of reason, with reference to thecognitions to which it strives to attain without the aid ofexperience; in other words, the solution of the question regardingthe possibility or impossibility of metaphysics, and the determinationof the origin, as well as of the extent and limits of this science.All this must be done on the basis of principles.This path--the only one now remaining--has been entered upon byme; and I flatter myself that I have, in this way, discovered thecause of--and consequently the mode of removing--all the errorswhich have hitherto set reason at variance with itself, in thesphere of non-empirical thought. I have not returned an evasive answerto the questions of reason, by alleging the inability and limitationof the faculties of the mind; I have, on the contrary, examined themcompletely in the light of principles, and, after having discoveredthe cause of the doubts and contradictions into which reason fell,have solved them to its perfect satisfaction. It is true, thesequestions have not been solved as dogmatism, in its vain fancies anddesires, had expected; for it can only be satisfied by the exerciseof magical arts, and of these I have no knowledge. But neither do thesecome within the compass of our mental powers; and it was the duty ofphilosophy to destroy the illusions which had their origin inmisconceptions, whatever darling hopes and valued expectations maybe ruined by its explanations. My chief aim in this work has beenthoroughness; and I make bold to say that there is not a singlemetaphysical problem that does not find its solution, or at leastthe key to its solution, here. Pure reason is a perfect unity; andtherefore, if the  principle presented by it prove to be insufficientfor the solution of even a single one of those questions to whichthe very nature of reason gives birth, we must reject it, as we couldnot be perfectly certain of its sufficiency in the case of the others.While I say this, I think I see upon the countenance of the readersigns of dissatisfaction mingled with contempt, when he hearsdeclarations which sound so boastful and extravagant; and yet theyare beyond comparison more moderate than those advanced by the commonestauthor of the commonest philosophical programme, in which thedogmatist professes to demonstrate the simple nature of the soul, orthe necessity of a primal being. Such a dogmatist promises to extendhuman knowledge beyond the limits of possible experience; while Ihumbly confess that this is completely beyond my power. Instead ofany such attempt, I confine myself to the examination of reason aloneand its pure thought; and I do not need to seek far for thesum-total of its cognition, because it has its seat in my own mind.Besides, common logic presents me with a complete and systematiccatalogue of all the simple operations of reason; and it is my taskto answer the question how far reason can go, without the materialpresented and the aid furnished by experience.So much for the completeness and thoroughness necessary in theexecution of the present task. The aims set before us are notarbitrarily proposed, but are imposed upon us by the nature ofcognition itself.The above remarks relate to the matter of our critical inquiry. Asregards the form, there are two indispensable conditions, which anyone who undertakes so difficult a task as that of a critique of purereason, is bound to fulfil. These conditions are certitude andclearness.As regards certitude, I have fully convinced myself that, in thissphere of thought, opinion is perfectly inadmissible, and thateverything which bears the least semblance of an hypothesis must beexcluded, as of no value in such discussions. For it is a necessarycondition of every cognition that is to be established upon a priorigrounds that it shall be held to be absolutely necessary; much moreis this the case with an attempt to determine all pure a prioricognition, and to furnish the standard--and consequently an example--of all apodeictic (philosophical) certitude. Whether I havesucceeded in what I professed to do, it is for the reader todetermine; it is the author's business merely to adduce grounds andreasons, without determining what influence these ought to have onthe mind of his judges. But, lest anything he may have said may becomethe innocent cause of doubt in their minds, or tend to weaken the effectwhich his arguments might otherwise produce--he may be allowed topoint out those passages which may occasion mistrust or difficulty,although these do not concern the main purpose of the present work.He does this solely with the view of removing from the mind of thereader any doubts which might affect his judgement of the work as awhole, and in regard to its ultimate aim.I know no investigations more necessary for a full insight intothe nature of the faculty which we call understanding, and at the sametime for the determination of the rules and limits of its use, thanthose undertaken in the second chapter of the "TranscendentalAnalytic," under the title of "Deduction of the Pure Conceptions ofthe Understanding"; and they have also cost me by far the greatestlabour--labour which, I hope, will not remain uncompensated. Theview there taken, which goes somewhat deeply into the subject, hastwo sides, The one relates to the objects of the pure understanding,and is intended to demonstrate and to render comprehensible theobjective validity of its a priori conceptions; and it forms forthis reason an essential part of the Critique. The other considersthe pure understanding itself, its possibility and its powers ofcognition--that is, from a subjective point of view; and, althoughthis exposition is of great importance, it does not belong essentiallyto the main purpose of the work, because the grand question is whatand how much can reason and understanding, apart from experience,cognize, and not, how is the faculty of thought itself possible? Asthe latter is an, inquiry into the cause of a given effect, and hasthus in it some semblance of an hypothesis (although, as I shallshow on another occasion, this is really not the fact), it wouldseem that, in the present instance, I had allowed myself to enouncea mere opinion, and that the reader must therefore be at liberty tohold a different opinion. But I beg to remind him that, if mysubjective deduction does not produce in his mind the conviction ofits certitude at which I aimed, the objective deduction, with whichalone the present work is properly concerned, is in every respectsatisfactory.