This chapter presents a selection of the notes that Kant made in 1764–65 in his own interleaved copy of his 1764 work Observations on the Feeling of the Beautiful and Sublime (Beobachtungen über das Gefühl des Schönen und Erhabenen). This popular work, organized around the division of aesthetic responses into the feelings of the beautiful and of the sublime that Edmund Burke had made canonical in his 1757 book A Philosophical Enquiry into the Origin of Our Ideas of the Sublime and Beautiful, is primarily devoted to an exploration of differences in the aesthetic preferences between the two genders and among different nationalities and races; it offers no analysis of the concepts or experiences of the beautiful and sublime themselves and therefore foreshadows nothing of the distinctive theories of the beautiful and the sublime that Kant would offer many years later in the Critique of the Power of Judgment (1790). But the work does explore connections between the different preferences for the beautiful and the sublime and differences in moral sentiment and character, and that may be why Kant was prompted to use this volume in the months following its publication to write some of the first notes that reflect his emerging moral theory.

Kant's short treatise, Über eine Entdeckung, nach der alle neue Kritik der reinen Vernunft durch eine ältere entbehrlich gemacht werden soll (On a Discovery whereby Any New Critique of Pure Reason Is to Be Made Superfluous by an Older One, henceforth to be referred to as On a Discovery) appeared in April, 1790, simultaneously with the Critique of Judgment, to which it alludes in its closing pages. It is a polemical piece, containing Kant's response to the critique of his philosophy launched by the Wolffian philosopher and professor at Halle, Johann August Eberhard (1739–1809).

Eberhard's opposition to Kant's philosophy dates back to the first appearance of the Critique of Pure Reason (1781), and he continually criticized it in his lectures. With the publication of the second edition in 1787, however, he evidently felt the need to make his opposition known to a wider public. Thus, together with other Wolffians, most notably J. G. Mass and J. E. Schwab, he founded in 1788 a journal, the Philosophisches Magazin, the general purpose of which was to provide an organ for a full-scale attack on the Kantian philosophy from the standpoint of the rationalism of Leibniz and Wolff. More specifically, its intent was to counter the Allgemeine Literatur-Zeitung, a journal which had been founded in Jena in 1785 by Kant's friend and ally J. G. Schultz for the purpose of defending and promulgating the critical philosophy.

In an essay in the Berliner Monatsschrift (May 1796, pp. 395–96), among other examples of the fanaticism that may be induced by attempts to philosophize about mathematical objects, I also attributed to the Pythagorean number-mystic the question: “Why is it that the ratio of the three sides of a right-angled triangle can only be that of the numbers 3, 4, and 5?” I had thus taken this proposition to be true; but Professor Reimarus refutes it, and shows (Berliner Monatsschrift, August, no. 6) that many numbers, other than those mentioned, can stand in the ratio in question.

So nothing seems clearer than that we find ourselves embroiled in a truly mathematical dispute (of a kind that is, in general, almost unheard of). But this quarrel amounts only to a misunderstanding. Each party takes the expression in a different sense; so soon as a mutual understanding is reached, the dispute vanishes, and both sides are correct. Now proposition and counter-proposition are related as follows:

R. says (or at least thinks his proposition thus): “In the infinite multitude of all possible numbers (considered at large) there exist, in regard to the sides of the right-angled triangle, more ratios than that of the numbers 3, 4, and 5.”

The Metaphysische Anfangsgründe der Naturwissenschaft (hereinafter: Metaphysical Foundations) first appeared in 1786 (with second and third printings in 1787 and 1800 respectively). This work thus belongs to the most creative decade of Kant's so-called critical period: the decade of the first edition of the Critique of Pure Reason (1781), the Prolegomena (1783), the Groundwork of the Metaphysics of Morals (1785), the second edition of the Critique of Pure Reason (1787), the Critique of Practical Reason (1788), and finally the Critique of Judgement (1790). Until very recently, however, the Metaphysical Foundations has had by far the least impact of any of these works, and has accordingly attracted the least amount of scholarly attention. Both the content and the form of the work have contributed to this situation. For, on the one hand, the Metaphysical Foundations is concerned with relatively specialized questions belonging to natural philosophy and even to physics: questions about the character and behavior of attractive and repulsive forces, for example, or about impact and the communication of motion. And, on the other hand, it is written in an inhospitable and forbidding style – organized in quasi-mathematical fashion into definitions (“explications”), propositions, proofs, remarks, and so on. In both of these respects the Metaphysical Foundations is more akin to some of Kant's precritical writings on natural philosophy – especially the Physical Monadology (1756) – than to the great works of the critical period.

The Prolegomena to Any Future Metaphysics is the preeminent synopsis in the history of philosophy. Kant completed it about fifteen months after the Critique of Pure Reason was published. He wanted to present his critical philosophy concisely and accessibly, for “future teachers” of metaphysics. He also wanted to convince his fellow metaphysicians “that it is unavoidably necessary to suspend their work for the present,” until they have determined “whether such a thing as metaphysics is even possible at all” (4:255). Although the Critique “always remains the foundation to which the Prolegomena refer only as preparatory exercises” (4:261), Kant nonetheless hoped that the shorter work would be used to assess the critical philosophy “piece by piece from its foundation,” serving “as a general synopsis, with which the work itself could then be compared on occasion” (4:380).

In the Prolegomena, Kant distilled his critical inquiry into the General Question, “Is metaphysics possible at all?” (4:271), which he in turn interpreted as a question about the possibility of synthetic a priori cognition (4:275–6), or cognition through pure reason (that is, independent of sensory experience). To answer the General Question, Kant first asked how synthetic a priori cognition is possible in two areas where he considered it actual: pure mathematics and pure natural science. He found that this possibility (and actuality) could be explained only by positing cognitive structures that the subject brings to cognition, as forms of sensory intuition and categories of the understanding.

Welches sind die wirklichen Fortschritte, die die Metaphysik seit Leibnitzens und Wolf's Zeiten in Deutschland gemacht hat? (What Real Progress Has Metaphysics Made in Germany since the Time of Leibniz and Wolff?, henceforth to be referred to as Progress) constitutes Kant's projected, but never submitted or even completed, contribution to the prize essay contest on that topic announced by the Académie Royal des Sciences et des Belles-Lettres in Berlin. Unfortunately, Kant's original manuscript has been lost, and the text that we have is a compilation of three different manuscripts by Kant's friend and dinner companion Friedrich Theodor Rink. Kant apparently gave the material to Rink sometime between 1800 and 1802, and Rink published it in April, 1804, two months after Kant's death.

The proposed topic for the essay contest was first announced within the Academy itself on January 24, 1788, with the expectation that the public announcement would be made the following year. For some reason, however, the Academy failed to announce the contest until 1790, at which time it set a deadline for contributions of January 1, 1792. But having by then received only one submission, that of the Wolffian Johann Christ of Schwab (a collaborator with Eberhard on the anti-Kantian Philosophisches Magazin – see the introduction to On a Discovery), the Academy extended the submission date to June 1, 1795, and doubled the prize.

This volume, which is devoted to Kant's theoretical writings after 1781 (the time of the publication of the first edition of the Critique of Pure Reason), contains the following works: Prolegomena to Any Future Metaphysics (1783) [to be referred to as Prolegomena]; Metaphysical Foundations of Natural Science (1786) [to be referred to as Metaphysical Foundations]; On a Discovery whereby Any New Critique of Pure Reason Is to Be Made Superfluous by an Older One (1790) [to be referred to as On a Discovery]; What Real Progress Has Metaphysics Made in Germany since the Time of Leibniz and Wolff? (written during 1793–4, but only published after Kant's death in 1804) [to be referred to as Progress]; and the companion pieces: “On a Recently Prominent Tone of Superiority in Philosophy” and “Proclamation of the Imminent Conclusion of a Treaty of Perpetual Peace in Philosophy” (1796) [to be referred to as Tone and Proclamation, respectively].

Together these writings constitute only a small portion of Kant's total output after 1781, which includes the Groundwork to the Metaphysics of Morals (1785), the Critique of Practical Reason (1788), the Critique of Judgment (1790), Religion within the Boundaries of Mere Reason (1793), Perpetual Peace (1795), and the Metaphysics of Morals (1797), as well as many other writings (both substantive and occasional) dealing with religious, historical, political, and scientific issues.

Von einem neuerdings erhobenen vornehmen Ton in der Philosophie was first published in May, 1796, in the Berlinische Monatsschrift 27, 387–426. It was the opening shot in a controversy that later drew in a number of other writers, and to which Kant was to contribute a second essay: Verkündigung des nahen Abschlusses eines Traktats zum ewigen Frieden in der Philosophie, which appeared in December of that year (BM 28, 485–504). In the meantime, a side-dispute had also broken out with the mathematician J. A. H. Reimarus, over an allusion to Pythagorean triangles in the first essay; it led Kant to pen a brief explanation: Ausgleichung eines auf Missverstand beruhenden mathematischen Streits, which was printed in the August, 1796, number of the same journal. It had nothing to do with the main issues in contention, and in some editions of Kant's works has become detached from its context, to lead a separate existence of its own. It has here been inserted in its proper place.

Kant's attack on fine airs in philosophy, and the “proclamation of peace” that succeeded it, are primarily directed at the writings of Johann Georg Schlosser, a retired administrator and gentleman-amateur in philosophy, who happened also to be Goethe's brother-in-law. Having published, in 1795, a translation of Plato's letters, Schlosser had joined forces with another amateur Platonist, translator, and poetical light of the Göttinger Dichterbund, Count Friedrich Leopold zu Stolberg (1750–1819).

Within a few years of the publication of his Critique of Pure Reason in 1781, Immanuel Kant (1724–1804) was recognized by his contemporaries as one of the seminal philosophers of modern times – indeed as one of the great philosophers of all time. This renown soon spread beyond German-speaking lands, and translations of Kant's work into English were published even before 1800. Since then, interpretations of Kant's views have come and gone and loyalty to his positions has waxed and waned, but his importance has not diminished. Generations of scholars have devoted their efforts to producing reliable translations of Kant into English as well as into other languages.

There are four main reasons for the present edition of Kant's writings:

1. Completeness. Although most of the works published in Kant's lifetime have been translated before, the most important ones more than once, only fragments of Kant's many important unpublished works have ever been translated. These include the Opus postumum, Kant's unfinished magnum opus on the transition from philosophy to physics; transcriptions of his classroom lectures; his correspondence; and his marginalia and other notes. One aim of this edition is to make a comprehensive sampling of these materials available in English for the first time.

1. …

Section One

Happy Outlook for Imminent Perpetual Peace From the Lowest Level of Man's Living Nature to his Highest, that of Philosophy

Chrysippus says, in his pithy Stoic way: “Nature has given the pig a soul, instead of salt, so that he should not become rotten.” Now this is the lowest level of man's nature, prior to all cultivation, namely that of mere animal instinct. But it seems as if here the philosopher has thrown a prophetic glance into the physiological systems of our own day; save only that now, instead of the word ‘soul’, we have taken to using that of living force (and rightly so, since from an effect we can certainly infer to the force that produces it, but not forthwith to a substance specially adapted to this type of effect); we locate life, therefore, in the action of animating forces (life-impulse) and the ability to react to them (living-capacity), and call that man healthy in whom a proportionate stimulus produces neither an excessive nor an altogether too small effect: while conversely, the animalic operation of nature will pass over into a chemical one, which has decay as its consequence, so that it is not (as used to be thought) decay that must follow from and after death, but death that must follow from the preceding decay.