Section 4
Original German
§ 4.
Wäre Metaphysik, die sich als Wissenschaft behaupten könnte, wirklich; könnte man sagen: hier ist Metaphysik, die dürft ihr nur lernen, und sie wird euch unwiderstehlich und unveränderlich von ihrer Wahrheit überzeugen: so wäre diese Frage unnöthig, und es bliebe nur diejenige übrig, die mehr eine Prüfung unserer Scharfsinnigkeit, als den Beweis von der Existenz der Sache selbst beträfe, nämlich wie sie möglich sei, und wie Vernunft es anfange, dazu zu gelangen. Nun ist es der menschlichen Vernunft in diesem Falle so gut nicht geworden. Man kann kein einziges Buch aufzeigen, so wie man etwa einen Euklid vorzeigt, und sagen: das ist Metaphysik, hier findet ihr den vornehmsten Zweck dieser Wissenschaft, das Erkenntniß eines höchsten Wesens und einer künftigen Welt, bewiesen aus Principien der reinen Vernunft. Denn man kann uns zwar viele Sätze aufzeigen, die apodiktisch gewiß sind und niemals gestritten worden; aber diese sind insgesammt analytisch und betreffen mehr die Materialien und den Bauzeug zur Metaphysik, als die Erweiterung der Erkenntniß, die doch unsere eigentliche Absicht mit ihr sein soll (§ 2. litt. c). Ob ihr aber gleich auch synthetische Sätze (z. B. den Satz des zureichenden Grundes) vorzeigt, die ihr niemals aus bloßer Vernunft, mithin, wie doch eure Pflicht war, a priori bewiesen habt, die man euch aber doch gerne einräumt: so gerathet ihr doch, wenn ihr euch derselben zu eurem Hauptzwecke bedienen wollt, in so unstatthafte und unsichere Behauptungen, daß zu aller Zeit eine Metaphysik der anderen entweder in Ansehung der Behauptungen selbst, oder ihrer Beweise widersprochen und dadurch ihren Anspruch auf daurenden Beifall selbst vernichtet hat. Sogar sind die Versuche, eine solche Wissenschaft zu Stande zu bringen, ohne Zweifel die erste Ursache des so früh entstandenen Scepticismus gewesen, einer Denkungsart, darin die Vernunft so gewaltthätig gegen sich selbst verfährt, daß diese niemals, als in völliger Verzweiflung an Befriedigung in Ansehung ihrer wichtigsten Absichten hätte entstehen können. Denn lange vorher, ehe man die Natur methodisch zu befragen anfing, befrug man blos seine abgesonderte Vernunft, die durch gemeine Erfahrung in gewisser Maße schon geübt war, weil Vernunft uns doch immer gegenwärtig ist, Naturgesetze aber gemeiniglich mühsam aufgesucht werden müssen: und so schwamm Metaphysik oben auf wie Schaum, doch so, daß so wie der, den man geschöpft hatte, zerging, sich sogleich ein anderer auf der Oberfläche zeigte, den immer einige begierig aufsammleten, wobei andere, anstatt in der Tiefe die Ursache dieser Erscheinung zu suchen, sich damit weise dünkten, daß sie die vergebliche Mühe der erstern belachten.
Das Wesentliche und Unterscheidende der reinen mathematischen Erkenntniß von aller andern Erkenntniß a priori ist, daß sie durchaus nicht aus Begriffen, sondern jederzeit nur durch die Construction der Begriffe (Kritik S. 713) vor sich gehen muß. Da sie also in ihren Sätzen über den Begriff zu demjenigen, was die ihm correspondirende Anschauung enthält, hinausgehen muß: so können und sollen ihre Sätze auch niemals durch Zergliederung der Begriffe, d. i. analytisch, entspringen und sind daher insgesammt synthetisch.
Ich kann aber nicht umhin, den Nachteil zu bemerken, den die Vernachlässigung dieser sonst leichten und unbedeutend scheinenden Beobachtung der Philosophie zugezogen hat. Hume, als er den eines Philosophen würdigen Beruf fühlte, seine Blicke auf das ganze Feld der reinen Erkenntniß a priori zu werfen, in welchem sich der menschliche Verstand so große Besitzungen anmaßt, schnitt unbedachtsamer Weise eine ganze und zwar die erheblichste Provinz derselben, nämlich reine Mathematik, davon ab in der Einbildung, ihre Natur und so zu reden ihre Staatsverfassung beruhe auf ganz andern Principien, nämlich lediglich auf dem Satze des Widerspruchs; und ob er zwar die Eintheilung der Sätze nicht so förmlich und allgemein oder unter der Benennung gemacht hatte, als es von mir hier geschieht, so war es doch gerade so viel, als ob er gesagt hätte: reine Mathematik enthält blos analytische Sätze, Metaphysik aber synthetische a priori. Nun irrte er hierin gar sehr, und dieser Irrthum hatte auf seinen ganzen Begriff entscheidend nachtheilige Folgen. Denn wäre das von ihm nicht geschehen, so hätte er seine Frage wegen des Ursprungs unserer synthetischen Urtheile weit über seinen metaphysischen Begriff der Causalität erweitert und sie auch auf die Möglichkeit der Mathematik a priori ausgedehnt; denn diese mußte er eben sowohl für synthetisch annehmen. Alsdann aber hätte er seine metaphysische Sätze keinesweges auf bloße Erfahrung gründen können, weil er sonst die Axiomen der reinen Mathematik ebenfalls der Erfahrung unterworfen haben würde, welches zu thun er viel zu einsehend war. Die gute Gesellschaft, worin Metaphysik alsdann zu stehen gekommen wäre, hätte sie wider die Gefahr einer schnöden Mißhandlung gesichert; denn die Streiche, welche der letzern zugedacht waren, hätten die erstere auch treffen müssen, welches aber seine Meinung nicht war, auch nicht sein konnte: und so wäre der scharfsinnige Mann in Betrachtungen gezogen worden, die denjenigen hätten ähnlich werden müssen, womit wir uns jetzt beschäftigen, die aber durch seinen unnachahmlich schönen Vortrag unendlich würden gewonnen haben.
Eigentlich metaphysische Urtheile sind insgesammt synthetisch. Man muß zur Metaphysik gehörige von eigentlich metaphysischen Urtheilen unterscheiden. Unter jenen sind sehr viele analytisch, aber sie machen nur die Mittel zu metaphysischen Urtheilen aus, auf die der Zweck der Wissenschaft ganz und gar gerichtet ist, und die allemal synthetisch sind. Denn wenn Begriffe zur Metaphysik gehören, z. B. der von Substanz, so gehören die Urtheile, die aus der bloßen Zergliederung derselben entspringen, auch nothwendig zur Metaphysik, z. B. Substanz ist dasjenige, was nur als Subject existirt etc., und vermittelst mehrerer dergleichen analytischen Urtheile suchen wir der Definition der Begriffe nahe zu kommen. Da aber die Analysis eines reinen Verstandesbegriffs (dergleichen die Metaphysik enthält) nicht auf andere Art vor sich geht, als die Zergliederung jedes andern, auch empirischen Begriffs, der nicht in die Metaphysik gehört (z. B. Luft ist eine elastische Flüssigkeit, deren Elasticität durch keinen bekannten Grad der Kälte aufgehoben wird), so ist zwar der Begriff, aber nicht das analytische Urtheil eigenthümlich metaphysisch: denn diese Wissenschaft hat etwas Besonderes und ihr Eigenthümliches in der Erzeugung ihrer Erkenntnisse a priori, die also von dem, was sie mit allen andern Verstandeserkenntnissen gemein hat, muß unterschieden werden; so ist z. B. der Satz: alles, was in den Dingen Substanz ist, ist beharrlich, ein synthetischer und eigenthümlich metaphysischer Satz.
Wenn man die Begriffe a priori, welche die Materie der Metaphysik und ihr Bauzeug ausmachen, zuvor nach gewissen Principien gesammlet hat, so ist die Zergliederung dieser Begriffe von großem Werthe; auch kann dieselbe als ein besonderer Theil (gleichsam als philosophia definitiva), der lauter analytische, zur Metaphysik gehörige Sätze enthält, von allen synthetischen Sätzen, die die Metaphysik selbst ausmachen, abgesondert vorgetragen werden. Denn in der That haben jene Zergliederungen nirgend anders einen beträchtlichen Nutzen, als in der Metaphysik, d. i. in Absicht auf die synthetischen Sätze, die aus jenen zuerst zergliederten Begriffen sollen erzeugt werden.
Der Schluß dieses Paragraphs ist also: daß Metaphysik es eigentlich mit synthetischen Sätzen a priori zu thun habe, und diese allein ihren Zweck ausmachen, zu welchem sie zwar allerdings mancher Zergliederungen ihrer Begriffe, mithin analytischer Urtheile bedarf, wobei aber das Verfahren nicht anders ist, als in jeder andern Erkenntnißart, wo man seine Begriffe durch Zergliederung blos deutlich zu machen sucht. Allein die Erzeugung der Erkenntniß a priori sowohl der Anschauung als Begriffen nach, endlich auch synthetischer Sätze a priori und zwar im philosophischen Erkenntnisse machen den wesentlichen Inhalt der Metaphysik aus.
Überdrüssig also des Dogmatismus, der uns nichts lehrt, und zugleich des Scepticismus, der uns gar überall nichts verspricht, auch nicht einmal den Ruhestand einer erlaubten Unwissenheit, aufgefordert durch die Wichtigkeit der Erkenntniß, deren wir bedürfen, und mißtrauisch durch lange Erfahrung in Ansehung jeder, die wir zu besitzen glauben, oder die sich uns unter dem Titel der reinen Vernunft anbietet, bleibt uns nur noch eine kritische Frage übrig, nach deren Beantwortung wir unser künftiges Betragen einrichten können: Ist überall Metaphysik möglich? Aber diese Frage muß nicht durch sceptische Einwürfe gegen gewisse Behauptungen einer wirklichen Metaphysik (denn wir lassen jetzt noch keine gelten), sondern aus dem nur noch problematischen Begriffe einer solchen Wissenschaft beantwortet werden.
In der Kritik der reinen Vernunft bin ich in Absicht auf diese Frage synthetisch zu Werke gegangen, nämlich so, daß ich in der reinen Vernunft selbst forschte und in dieser Quelle selbst die Elemente sowohl, als auch die Gesetze ihres reinen Gebrauchs nach Prinzipien zu bestimmen suchte. Diese Arbeit ist schwer und erfordert einen entschlossenen Leser, sich nach und nach in ein System hinein zu denken, was noch nichts als gegeben zum Grunde legt außer die Vernunft selbst und also, ohne sich auf irgend ein Factum zu stützen, die Erkenntniß aus ihren ursprünglichen Keimen zu entwickeln sucht. Prolegomena sollen dagegen Vorübungen sein; sie sollen mehr anzeigen, was man zu thun habe, um eine Wissenschaft wo möglich zur Wirklichkeit zu bringen, als sie selbst vortragen. Sie müssen sich also auf etwas stützen, was man schon als zuverlässig kennt, von da man mit Zutrauen ausgehen und zu den Quellen aufsteigen kann, die man noch nicht kennt, und deren Entdeckung uns nicht allein das, was man wußte, erklären, sondern zugleich einen Umfang vieler Erkenntnisse, die insgesammt aus den nämlichen Quellen entspringen, darstellen wird. Das methodische Verfahren der Prolegomenen, vornehmlich derer, die zu einer künftigen Metaphysik vorbereiten sollen, wird also analytisch sein.
Es trifft sich aber glücklicher Weise, daß, ob wir gleich nicht annehmen können, daß Metaphysik als Wissenschaft wirklich sei, wir doch mit Zuversicht sagen können, daß gewisse reine synthetische Erkenntniß a priori wirklich und gegeben sei, nämlich reine Mathematik und reine Naturwissenschaft; denn beide enthalten Sätze, die theils apodiktisch gewiß durch bloße Vernunft, theils durch die allgemeine Einstimmung aus der Erfahrung und dennoch als von Erfahrung unabhängig durchgängig anerkannt werden. Wir haben also einige wenigstens unbestrittene synthetische Erkenntniß a priori und dürfen nicht fragen, ob sie möglich sei (denn sie ist wirklich), sondern nur wie sie möglich sei, um aus dem Princip der Möglichkeit der gegebenen auch die Möglichkeit aller übrigen ableiten zu können.
Prolegomena.
Allgemeine Frage:
Wie ist Erkenntniß aus reiner Vernunft möglich?
Musean translation
Mouseia’s complete machine-assisted Musean translation, made directly from the complete German of the Prolegomena (AA IV 253–383, all §§1–60 and the Appendix), for fidelity, the steps of Kant’s argument, clarity and structure.
§ 4.
If a metaphysics capable of maintaining its standing as a science actually existed; if we could say, “Here is metaphysics: you need only learn it, and it will convince you of its truth irresistibly and permanently,” then this question would be needless. Only the further question would remain, one that concerns a test of our acumen rather than a proof of the thing’s existence: how it is possible, and how reason sets about attaining it. But in this case human reason has not been so fortunate. We cannot point to a single book, as we might present a work of Euclid, and say: this is metaphysics; here you will find the chief aim of this science, cognition of a highest being and a future world, demonstrated from principles of pure reason. We can indeed be shown many propositions that are apodictically certain and have never been disputed; but they are all analytic, and concern the materials and building supplies for metaphysics rather than the enlargement of cognition that ought to be our proper purpose in pursuing it (§ 2, letter c). Even if you also present synthetic propositions—for example, the principle of sufficient reason—which you have never proved from reason alone, hence a priori, as was your duty, but which people nevertheless readily grant you, you still fall into such untenable and uncertain assertions when you try to use them for your principal aim that at all times one metaphysics has contradicted another, either in its assertions themselves or in their proofs, and thereby destroyed its own claim to lasting acceptance. Indeed, attempts to bring such a science into being were undoubtedly the first cause of skepticism’s early appearance: a way of thinking in which reason acts so violently against itself that it could have arisen only in complete despair of satisfying its most important aims. For long before people began to question nature methodically, they questioned only their own isolated reason, which ordinary experience had already exercised to some extent. They did so because reason is always present to us, whereas the laws of nature must generally be sought with difficulty. And so metaphysics floated on the surface like foam: as soon as what had been scooped up dissolved, more appeared on the surface, always eagerly gathered by some, while others, instead of seeking in the depths the cause of this appearance, thought themselves wise for laughing at the former’s fruitless labor.
The essential feature distinguishing pure mathematical cognition from all other cognition a priori is that it must proceed not from concepts at all, but always only through the construction of concepts (Critique, page 713). Since in its propositions it must therefore go beyond the concept to what is contained in the intuition corresponding to it, its propositions can never—and should never—arise through the analysis of concepts, that is, analytically; hence they are all synthetic.
I cannot, however, refrain from noting the harm done to philosophy by neglecting this otherwise easy and seemingly insignificant observation. When Hume felt the calling, worthy of a philosopher, to cast his eyes over the whole field of pure cognition a priori, in which the human understanding lays claim to such vast possessions, he thoughtlessly cut off an entire province—indeed, the most important one—namely pure mathematics. He imagined that its nature and, so to speak, its constitution rested on quite different principles, namely on the principle of contradiction alone. Although he did not divide propositions as formally or universally, or under the same names, as I do here, it amounted to his saying: pure mathematics contains only analytic propositions, but metaphysics contains synthetic propositions a priori. In this he was greatly mistaken, and the mistake had decisively harmful consequences for his whole conception. Had he not made it, he would have extended his question about the origin of our synthetic judgments far beyond his metaphysical concept of causality, to include the possibility of mathematics a priori; for he would have had to acknowledge mathematics as synthetic as well. But then he could by no means have grounded his metaphysical propositions on mere experience, since he would otherwise have subjected the axioms of pure mathematics to experience too, and he had far too much insight to do that. The good company in which metaphysics would then have found itself would have secured it against the danger of contemptuous mistreatment: the blows intended for metaphysics would also have had to strike mathematics, which was not, and could not have been, his intention. Thus this acute thinker would have been drawn into reflections that would have had to resemble those occupying us now, but which would have gained immeasurably from his inimitably beautiful presentation.
Properly metaphysical judgments are all synthetic. We must distinguish judgments belonging to metaphysics from judgments that are properly metaphysical. Among the former, very many are analytic; but they constitute only the means to metaphysical judgments, toward which the science’s aim is wholly directed, and which are always synthetic. For if concepts belong to metaphysics—for example, the concept of substance—then judgments arising from their mere analysis necessarily belong to metaphysics as well: for example, substance is that which exists only as subject, and so forth. By means of several such analytic judgments we seek to approach the definition of the concepts. But the analysis of a pure concept of the understanding, such as metaphysics contains, proceeds no differently from the analysis of any other concept, including an empirical one not belonging to metaphysics—for example, air is an elastic fluid whose elasticity is not abolished by any known degree of cold. Thus the concept, but not the analytic judgment, is distinctively metaphysical. For this science has something special and distinctive in the generation of its cognitions a priori, which must therefore be distinguished from what it shares with all other cognitions of the understanding. Thus, for example, the proposition “Everything in things that is substance is permanent” is a synthetic and distinctively metaphysical proposition.
Once the concepts a priori that constitute the material and building supplies of metaphysics have been assembled according to certain principles, the analysis of these concepts is of great value. It can also be presented separately as a special part—a kind of philosophia definitiva, or philosophy of definitions—containing only analytic propositions belonging to metaphysics, apart from all the synthetic propositions that constitute metaphysics itself. For in fact these analyses have no considerable use anywhere except in metaphysics, that is, with a view to the synthetic propositions that are to be generated from those concepts after their initial analysis.
The conclusion of this section, then, is that metaphysics is properly concerned with synthetic propositions a priori, and these alone constitute its aim. For this it certainly needs many analyses of its concepts, hence analytic judgments; but the procedure here is no different from that in any other kind of cognition where we seek merely to make our concepts distinct by analyzing them. The generation of cognition a priori, however, both in intuition and in concepts, and finally also of synthetic propositions a priori—and specifically within philosophical cognition—constitutes the essential content of metaphysics.
Weary, then, of a dogmatism that teaches us nothing, and at the same time of a skepticism that promises us nothing at all, not even the repose of a permissible ignorance; summoned by the importance of the cognition we need, and made distrustful by long experience of every cognition we believe we possess, or that offers itself under the title of pure reason, we are left with only one critical question, whose answer can guide our future conduct: Is metaphysics possible at all? But this question must be answered not through skeptical objections to particular assertions of an actual metaphysics—for at present we acknowledge none—but from the still merely problematic concept of such a science.
In the Critique of Pure Reason I proceeded synthetically with regard to this question: I investigated pure reason itself and sought, in this very source, to determine according to principles both the elements and the laws of its pure use. This work is difficult. It requires a resolute reader to think his way gradually into a system that takes nothing as given for its foundation except reason itself, and thus seeks, without relying on any fact, to unfold cognition from its original seeds. Prolegomena, by contrast, are to be preliminary exercises; they should indicate what must be done to bring a science into actuality if possible, rather than present the science itself. They must therefore rest on something already known to be reliable, from which we can confidently set out and ascend to sources not yet known, whose discovery will not only explain what we knew but also display a range of many cognitions all springing from those same sources. The methodical procedure of prolegomena, particularly those intended to prepare for a future metaphysics, will therefore be analytic.
Fortunately, however, although we cannot assume that metaphysics as a science is actual, we can confidently say that certain pure synthetic cognitions a priori are actual and given: namely, pure mathematics and pure natural science. Both contain propositions universally acknowledged, some as apodictically certain through reason alone, others through the universal agreement of experience, yet throughout as independent of experience. We therefore possess at least some undisputed synthetic cognition a priori, and need not ask whether it is possible—for it is actual—but only how it is possible, so that from the principle of the possibility of what is given we may also derive the possibility of all the rest.
Prolegomena.
General Question:
How Is Cognition from Pure Reason Possible?
Plain English translation
Mouseia’s complete Plain English edition, made independently and directly from the same complete German text.
§ 4.
If a metaphysics that could establish itself as a science actually existed, we could say: here is metaphysics; you need only learn it, and it will convince you of its truth irresistibly and permanently. In that case this question would be unnecessary. Only one question would remain, testing our insight rather than proving that the thing itself exists: how it is possible, and how reason manages to attain it. But human reason has not been so fortunate in this case. We cannot point to a single book, as we can, say, to Euclid, and say: this is metaphysics; here you will find the chief aim of this science, cognition of a supreme being and a future world, proved from principles of pure reason. Many propositions can indeed be shown to us that are apodictically certain and have never been disputed. But they are all analytic. They concern the materials and equipment for metaphysics more than the extension of cognition that should be our real aim in it (§ 2. litt. c). You may also present synthetic propositions, for example the principle of sufficient reason, which you have never proved from reason alone, and therefore a priori, as you were obliged to do. People gladly grant them to you all the same. But when you try to use them for your main purpose, you fall into claims so inadmissible and uncertain that, at all times, one metaphysics has contradicted another, either in the claims themselves or in their proofs. It has thereby destroyed its own claim to lasting acceptance. Indeed, attempts to bring such a science into existence were undoubtedly the first cause of skepticism's early appearance. This is a way of thinking in which reason acts so violently against itself that it could have arisen only in complete despair of finding satisfaction in its most important aims. Long before people began to question nature methodically, they questioned only their isolated reason, which ordinary experience had already trained to some degree. That is because reason is always present to us, whereas laws of nature usually have to be laboriously sought out. And so metaphysics floated on top like foam. As soon as the foam that had been scooped up dissolved, new foam appeared on the surface, which some people always eagerly collected. Others, instead of looking in the depths for the cause of this appearance, thought themselves wise because they laughed at the first group's wasted effort.
The essential feature that distinguishes pure mathematical cognition from every other a priori cognition is that it must proceed not from concepts, but always only through the construction of concepts (Kritik S. 713). Its propositions must therefore go beyond the concept to what is contained in the intuition corresponding to it. So its propositions can never, and must never, arise by analyzing concepts, that is, analytically. They are therefore all synthetic.
I cannot help pointing out the harm done to philosophy by neglecting this otherwise easy and seemingly insignificant observation. Hume felt the calling, worthy of a philosopher, to look over the whole field of pure a priori cognition, where human understanding claims such large possessions. But he carelessly cut off an entire province, indeed the most important one: pure mathematics. He imagined that its nature and, so to speak, its constitution rested on quite different principles, namely on the principle of contradiction alone. Although he did not divide propositions as formally and generally, or under the names I use here, it amounted to saying that pure mathematics contains only analytic propositions, while metaphysics contains synthetic a priori ones. He was very much mistaken in this, and the mistake had decisively harmful consequences for his whole conception. Had he not made it, he would have extended his question about the origin of our synthetic judgments far beyond his metaphysical concept of causality, to the possibility of a priori mathematics as well. For he would have had to recognize mathematics as synthetic too. But then he could not possibly have based his metaphysical propositions on experience alone, since he would also have subjected the axioms of pure mathematics to experience. He was far too perceptive to do that. The good company in which metaphysics would then have found itself would have protected it from the danger of degrading mistreatment. The blows intended for metaphysics would also have had to strike mathematics, which was not and could not have been his intention. This would have drawn that perceptive man into reflections that would have had to resemble those occupying us now, but that would have gained immeasurably from his inimitably beautiful presentation.
Properly metaphysical judgments are all synthetic. We must distinguish judgments belonging to metaphysics from metaphysical judgments proper. Many of the former are analytic, but they only supply the means for metaphysical judgments, which are the entire aim of the science and are always synthetic. If concepts belong to metaphysics—for example, the concept of substance—then judgments arising merely from their analysis necessarily belong to metaphysics too. For example: substance is what exists only as a subject, and so on. Through a number of such analytic judgments we try to approach the definition of the concepts. But the analysis of a pure concept of the understanding, of the kind metaphysics contains, proceeds no differently from the analysis of any other concept, even an empirical one that does not belong to metaphysics. For example: air is an elastic fluid whose elasticity is not canceled by any known degree of cold. So the concept is distinctively metaphysical, but the analytic judgment is not. This science has something special and distinctive in the production of its a priori cognitions. This production must therefore be distinguished from what the science shares with all other cognition through the understanding. Thus the proposition that everything in things that is substance persists is a synthetic and distinctively metaphysical proposition.
Once we have collected, according to certain principles, the a priori concepts that supply the material and equipment of metaphysics, analyzing these concepts is of great value. This analysis can also be presented separately, as a special part—a philosophy of definitions, so to speak—containing nothing but analytic propositions belonging to metaphysics. It can be kept separate from all the synthetic propositions that make up metaphysics itself. In fact, these analyses have no considerable use anywhere except in metaphysics: that is, with regard to the synthetic propositions that are to be produced from the concepts first analyzed.
The conclusion of this section is therefore that metaphysics properly concerns synthetic a priori propositions, and these alone make up its aim. For that purpose it certainly needs many analyses of its concepts, and thus analytic judgments. But here the procedure is no different from that in any other kind of cognition, where we seek merely to make our concepts clear by analyzing them. The essential content of metaphysics, however, is the production of a priori cognition, both in intuition and in concepts, and finally of synthetic a priori propositions within philosophical cognition.
We are tired, then, of dogmatism, which teaches us nothing, and of skepticism, which promises us nothing at all—not even the peaceful state of an allowable ignorance. The importance of the cognition we need urges us on, while long experience makes us distrust every cognition we believe we possess or that offers itself under the name of pure reason. Only one critical question remains. Its answer will let us decide how to proceed in the future: Is metaphysics possible at all? But this question must not be answered by skeptical objections to particular claims of an actual metaphysics, for we are not yet accepting any. It must be answered from the still merely problematic concept of such a science.
In the Critique of Pure Reason, I took a synthetic approach to this question. That is, I investigated pure reason itself and tried to determine, in that very source, both the elements and the laws of its pure use according to principles. This work is difficult. It requires determined readers to think their way gradually into a system that takes nothing as given for its foundation except reason itself. Without relying on any fact, it seeks to develop cognition from its original seeds. Prolegomena, by contrast, are meant to be preliminary exercises. Rather than present the science itself, they should indicate what must be done to bring a science into actual existence if possible. So they must rest on something already known to be reliable. From there we can start with confidence and ascend to sources we do not yet know. Discovering these sources will not only explain what we knew, but also reveal a range of many cognitions that all arise from those same sources. The method of the Prolegomena, especially of those intended to prepare for a future metaphysics, will therefore be analytic.
Fortunately, although we cannot assume that metaphysics actually exists as a science, we can confidently say that certain pure synthetic a priori cognition is actual and given: pure mathematics and pure natural science. Both contain propositions that are recognized throughout: some as apodictically certain through reason alone, others through general agreement with experience, yet still as independent of experience. So we have at least some undisputed synthetic a priori cognition. We need not ask whether it is possible, since it is actual, but only how it is possible. From the principle of the possibility of the cognition given, we can then derive the possibility of all the rest.
Prolegomena.
General Question:
How Is Cognition from Pure Reason Possible?
About this section
Section 4 is part of Prolegomena to Any Future Metaphysics by Immanuel Kant. This page sets the German original beside 2 direct-source translations, so any line can be checked against the source. It is section 8 of 72 in the work, which is kept in the European tradition.
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