Kant’s Life

One generally learns at least three things, however brief the sketch of Kant’s life: he never married, he never traveled, and he ordered his life so rigidly that the housewives of Königsberg could set their clocks to his daily walks. Like the spare lines of a caricature, these provide some sense of the man, but one could also point out in reply that Kant was by no means the first bachelor in the history of philosophy nor the only bachelor in Königsberg; that Kant actually managed to get out of town quite often, if not very far; and that only in his later years, when it appeared that his life-ambitions were outstripping his life, did he buckle-down and fashion himself into something more like a machine. The following will add some shading to those spare lines.¹

Kant’s early education

Immanuel Kant (1724-1804), arguably the most important Western philosopher since the Middle Ages, was born into a home of very modest means, at the far eastern end of the Baltic Sea in the bustling port city of Königsberg (now the Russian city of Kaliningrad). He was the fourth child and first surviving son in his family, with one older and three younger sisters and a younger brother who survived into adulthood.² He was born the same year as Königsberg itself, which had been formed by consolidating the three medieval towns of Kneiphof (a small island located where the New and Old Pregel rivers met), Altstadt (to the north), and Löbenicht (to the east). The Kants lived in that part of Königsberg given over to members of the harness and saddle guilds, in the Vorderste Vorstadt, just south of the Kneiphof island. At the east end of this island sat the fourteenth-century red brick cathedral, or Domkirche, where Kant’s parents had been married and where Kant and his siblings were later baptized. On the north side of this cathedral stood a few low buildings that made up the Academia Albertina, a Lutheran university founded in 1544 in the wake of the Protestant Reformation.

Kant received his first taste of student life at a German school in his neighborhood, where a single teacher gave instruction on reading, writing, arithmetic, and Christianity. There were a dozen of these so-called “church schools” – all Lutheran – scattered around the city and always affiliated with a church overseeing the instruction. A few of them were bilingual, offering instruction in German as well as in Polish or Lithuanian; one school was entirely in French, to serve the small community of French Huguenots; and another served the children from Catholic homes.³

Kant would not have attended this German school for many years, since he enrolled at the Collegium Fridericianum – a Pietist Latin school – when he was eight. This was at the urging of Franz Albrecht Schultz, a forty-year-old Pietist theologian and pastor who had arrived in Königsberg just the year before, and who must have noticed an intelligence in the young boy that deserved better cultivation. Schultz was the consistory advisor and pastor at the Altstadt Church, which managed the German school Kant was attending, and it was perhaps this connection that led Kant’s mother to attend Schultz’s bible study classes, to which she brought her older children, and that also led to Schultz’s occasional visits to the Kant home.⁴

Local children hoping to attend the university and too poor for a private tutor needed to study at one of the three Latin city schools or else at the Collegium Fridericianum, which had beds for about seventy-five boarders, and which also accepted day-students, of which Kant was one. From Easter 1732 (having just turned eight) until Michaelmas 1740 (when he was sixteen), Kant walked across town each day to attend this school. Classes began every morning at 7 a.m. and ended at 4 p.m., with time set aside for play and for worship. He attended as a charity student, and without Schultz’s intervention he likely would not have gone at all. Kant was grateful to Schultz for this,⁵ however much he disliked his years there – Kant’s friend Hippel later wrote that “terror and fear would overcome him as soon as he thought back to the slavery of his youth”⁶ – and his extreme distaste for institutional religion likely began at this time, as well.

Kant’s studies at the Collegium included Latin and theology for all seventeen of his semesters there, as well as Greek for at least ten semesters and Hebrew for eight, French for six, handwriting for eleven (at one point he fell back a level), singing for six, geography for at least four, history for three, antiquities for five, poetry for four, arithmetic for nine, mathematics for two, and philosophy beginning in his next to last year.⁷

The curriculum included nothing from the natural sciences, nor was there any study of modern literature. Instruction in Hebrew and Greek focused on Bible translation, with no classical Greek works. Of more relevance to Kant’s later philosophical career was the study of Cicero in the context of the Latin class. Kant excelled in Latin, becoming a fine stylist, and “even as an old man recited the most beautiful passages of Latin poets, orators, and historians.”⁸ But in general, as Kant once mentioned to a former classmate, “any sparks in us for philosophy or math could not be blown into a flame by those men,” to which the classmate replied: “But they were good at blowing them out.”⁹

Pietism and rationalism in Königsberg

Kant came of age in the wake of two strong challenges to orthodox Lutheran theology, Pietism and rationalism. Pietism was a revivalist, anti-intellectual movement within the context of the German Lutheran church that was inspired by Philipp Jakob Spener (1635-1705) and his Pia Desideria (1675), and it was similar to the Methodism that was sweeping England. In the words of Isaiah Berlin:

[Pietism] laid stress on the depth and sincerity of personal faith and direct union with God, achieved by scrupulous self-examination, passionate, intensely introspective religious feeling, and concentrated self-absorption and prayer, whereby the sinful, corrupt self was humbled and the soul left open to the blessing of divine, unmerited grace.¹⁰

Kant’s family belonged to this Pietist movement, as did all his instructors at school, so this religion deeply informed the first sixteen years of Kant’s life. The spiritual center for Pietism at the time was the university at Halle, the largest of the four Prussian universities (the others were Königsberg, Frankfurt/Oder, and Duisburg). August Hermann Francke (1663-1727) had studied under Spener at Dresden and then brought the movement to Halle, and he was instrumental in helping Friedrich Wilhelm I (who reigned from 1713 to 1740) install Pietists at the university in Königsberg.

Rationalism was championed by Christian Wolff (1679-1754), also at Halle, who developed a scholasticism consistent with the scientific advances of his day. He viewed the special revelation of scripture as consistent with, but separable from, the natural revelation of rational theology. Just a year before Kant was born, the Pietists had convinced the king to expel Wolff from Halle, having been particularly scandalized by the rectoral address Wolff gave on July 12, 1721 – “On the Moral Philosophy of the Chinese” – in which he argued that Chinese (i.e., Confucian) and Christian ethics were fundamentally the same, and thus that ethics as such was not in need of a special Christian revelation.¹¹

This struggle between the Pietists and the rationalists played itself out in Königsberg as well, but a peculiar blend of these two forces also emerged. Schultz had studied under both Francke and Wolff in Halle, and he managed to reconcile these seemingly antagonistic positions. He was sent to Königsberg precisely because of his Pietism, assumed the directorship of the Collegium Fridericianum shortly after arriving in town, and eventually helped oversee all the churches and schools. Yet in his inaugural dissertation he argued that faith and reason can be harmonized, and that Wolff’s philosophy is acceptable and even useful for the faith.

Wolff himself had maintained that “if anyone has ever understood him, it is Schultz in Königsberg.”¹² Kant’s student and later close friend, T. G. von Hippel (1741-96), studied theology under Schultz and wrote that he “taught me theology from a different perspective, bringing in so much philosophy that one was led to believe that Christ and his Apostles had all studied in Halle under Wolff.”¹³

Martin Knutzen (1713-51), under whom Kant would later study, had nearly completed his own studies when Schultz arrived in Königsberg, and under his influence soon developed much the same blend of rationalism and Pietism – what Erdmann described as a Pietist content of divine revelation trussed up in the Wolffian form of definitions, theorems, and lemmas.¹⁴ Both of these men were of considerable importance for Kant, shaping the intellectual backdrop of his early years as a student at the university.

Kant’s university studies

Kant’s transition into university life must have been exciting. Near the end of his last term at the Collegium Fridericianum in the summer of 1740, the old king died and on July 20th his son arrived in town to be installed as the new king, Friedrich II (later dubbed “the Great”), beginning what was to become a forty-six-year reign promoting Enlightenment ideals throughout the land, and particularly in the universities. Wolff was coaxed back to Halle from his chair in Marburg, and Pietists everywhere were put on notice. Two months after the coronation, Kant matriculated at the Academia Albertina. He was sixteen years old, a standard age for such beginnings.

Given Kant’s meager financial resources (he received some help from an uncle), it is striking that he never took a teaching position at his old Latin school to support himself, as many other poor students did (including Herder, thirty years later). Were his experiences there such that he could not bring himself to re-enter that world? Nor is there any evidence that Kant ever applied for one of the many stipendiums available to poorer students.¹⁵ If he lived at home with his father and younger siblings (his mother had died three years earlier), it was not for long, as we read of him living with friends and making small amounts on the side; for instance, he was in demand as a tutor. Christoph Friedrich Heilsberg, a student friend, wrote that Kant promised me his assistance, gave me books on the newer philosophy, and helped me with the lectures by Professors Ammon, Knutzen, and Teske, at least the hardest parts; all of this was done out of friendship. In the meantime he tutored several students for a small fee, which each gave to him readily.¹⁶

Kant also made money playing billiards and cards:

His only recreation was playing billiards, a game in which Wlömer and I were his constant companions. We had nearly perfected our game, and rarely returned home without some winnings. I paid my French teacher altogether from this income. As a consequence, persons refused to play with us, and we abandoned this source of income, and chose instead L’Hombre, which Kant played well.¹⁷ The little we know of Kant’s studies is that he attended lectures by C. F. Ammon (mathematics), J. G. Teske (experimental physics), Knutzen (mathematics, logic, metaphysics, and moral philosophy), and Schultz (theology).¹⁸ He may also have attended J. D. Kypke’s lectures on logic and metaphysics, since they were free. Rink reports that he took classes for “about three years.”¹⁹

Kant’s relationship with Knutzen is a puzzle. Kant’s early biographers describe a close mentoring relationship between Knutzen and Kant, and most accounts since have repeated and embellished this. According to Ludwig Ernst Borowski (1740-1831), one of Kant’s early students and earliest biographers, Knutzen “was the teacher with whom Kant felt most connected. He attended all his courses on philosophy and mathematics without interruption. … Knutzen … found in Kant splendid talents … eventually loaning him works by Newton.”²⁰ Yet when Knutzen mentions his better students, he does not mention Kant; nor does Kant mention Knutzen.²¹ Kant’s first work (Thoughts on the True Estimation of Living Forces [1746-49; LF 1:3-181]), which Borowski describes as Knutzen-inspired, was dedicated not to Knutzen but to J. C. Bohl, a professor of medicine at the university. Insofar as Knutzen had a favorite student, it was Friedrich Johann Buck (1722-86), the same Buck who in 1759 would be given the Professorship in Logic and Metaphysics, instead of Kant.²² So the relationship between Knutzen and Kant could not have been very close; what Kant did receive from him appears to have been this: an introduction to Wolffian metaphysics and to Newtonian science.

Becoming Professor Kant

“I do not intend to teach philosophy, but rather how to philosophize.”²³ Kant repeated this sentiment throughout his teaching career. He sought to help his students master an activity, rather than a set of dogma – how to think, rather than what to believe. Kant “compelled his hearers to think for themselves,” according to Herder, who studied with Kant in the early 1760s. Even during Kant’s first semesters as an instructor, Kant would “always remind us that he would not teach philosophy, but rather how to philosophize, etc. … To think for oneself – to investigate for oneself – to stand on one’s own feet – were expressions he uttered constantly.”²⁴

Kant was the first major modern philosopher to spend his life teaching at a university, and most of his immediate followers sought to make that their home as well. When Kant decided on this academic path is unclear, but it appears to have come rather late. Most students in the eighteenth century took classes for two to three years without seeking a degree; only those wishing to teach at the university needed one, either a doctorate to teach in theology, medicine, or law, or a master’s degree to teach in the philosophy faculty.²⁵

Kant stayed at the university, or at least with his friends in Königsberg, for eight years, until poverty forced him to leave in the summer or fall of 1748 to serve as a private tutor in the countryside, which he did for about five years²⁶ – three years in one home, and two in a second – working with young boys ranging in age from seven to fourteen. These tutoring positions were usually taken by young theology students waiting on their first church appointment, although this clearly was not Kant’s situation, who listed himself at the time as a “student of philosophy.”²⁷

Of the eight years between entering the university and leaving Königsberg, likely no more than three years were spent attending lectures, so how did Kant spend those remaining five years? Had he been pursuing an academic career, he would have written a Latin dissertation to present to the philosophy faculty, a prerequisite for graduation, but Kant did not do this. Instead he wrote a book on what he took to be an important physics problem of his day, and he wrote it in German for publication outside the university. This first publication – written between 1744 and 1747 and with printing concluded in 1749 – was a 240-page work that attempted to reconcile the Cartesian and Leibnizian accounts of force (Living Forces [1746-49; LF 1:3-181]),²⁸ and this was followed by a book nearly as long that offered a Newtonian account of the formation of the universe, also in German and published in 1755 (Universal Natural History and Theory of the Heavens [UNH 1:217-368]). Apart from that, Kant wrote a few shorter pieces for the local paper in the summer of 1754, perhaps after his return to Königsberg, on the rotation and age of the earth.

This scholarly activity suggests that Kant was looking to create a name for himself outside of academia, a path certainly in keeping with the careers of many of the individuals with whose ideas he was engaged: Descartes, Newton, Leibniz, and many of their followers.²⁹ And yet he returned to Königsberg in the summer of 1754, perhaps by then with the intention of teaching. He submitted his master’s thesis (“Succinct Exposition of Some Meditations on Fire” [MF 1:371-84]) the following spring on April 17, 1755, sat for the oral exam on May 13, and received his degree on June 12. He was then required to submit a second Latin thesis to receive the privilege of teaching at the university. This work – New Elucidation of the First Principles of Metaphysical Cognition (NE 1:387-416) – was publicly defended on September 27. And thus did Kant’s teaching career at the university begin. It lasted almost forty-one years.

Kant’s lectures and his students

Kant’s life was shaped by the rhythms of the academic year, which in Prussian universities was divided by Michaelmas (September 29) and Easter (fluctuating between March 22 and April 25), with a new semester beginning about two weeks after each of these dates: winter semester the second week of October, and summer semester sometime in April or May. Most classes – and all “public lecture” classes – met four times a week.

The philosophy faculty in eighteenth-century Königsberg included eight full professors, the occasional associate professor, and a fluctuating number of unsalaried lecturers (Privatdozenten) whose only remuneration came at the end of the semester, collected directly from the students and normally at the rate of four thaler per head.³⁰ Only two of the full professorships were what today would be thought of as philosophy, namely, logic/metaphysics and practical philosophy; the others were mathematics, physics, Oriental languages, rhetoric/history, Greek, and poetry. These salaried professors were required to offer “public lectures” (normally one each semester, and these students attended for free), but they also would offer various “private lectures” (alongside the Privatdozenten), which were paid for by the students directly.

Kant taught as a lecturer for twenty-nine semesters (1755 to 1770) before finally receiving the professorship in mathematics, which he quickly exchanged for the professorship in logic and metaphysics,³¹ teaching in that capacity for fifty-three semesters (1770 to 1796).³²

The records are incomplete, but Kant appears to have taught logic most often (56 times), followed by metaphysics (53) and physical geography (49). He taught these three courses nearly every semester until he became a full professor, after which he taught each of them once a year. His first course on anthropology was given in 1772-73, and every winter semester thereafter (for a total of 24 semesters). These four courses formed the core of his teaching as a full professor, with metaphysics and anthropology offered in the winter, and logic and physical geography in the summer. Kant also offered private lectures in mathematics nearly every semester at the beginning of his career, but abruptly stopped after 1763-64 (15 semesters total). Theoretical physics (21) and moral philosophy (28) were alternated during much of his career, along with natural law (12), which he first taught in 1767, and philosophical encyclopedia³³ (10), which he first taught in 1767-68. Occasional courses were given on natural theology (4) and pedagogy (4).

Kant and his early biographers claim that his classrooms were always well-attended, and the records tend to bear this out, but not always. Other well-regarded instructors were teaching the same courses as Kant – for instance, there might be four or five private courses on metaphysics, apart from the public course offered by the full professor – and yet there were fewer than 400 students enrolled at the university.³⁴ The competition for students must have been intense, especially among the unsalaried lecturers whose income was entirely tuition-based. Of the courses for which we have records, almost 10 percent of Kant’s private offerings were cancelled due to low enrollment.

Kant was an engaging lecturer. Christian Friedrich Jensch heard Kant during the winter semester of 1763-64:

How interesting Kant was in his lectures. He would enter the room in a sort of enthusiasm, saying: we left off here or there. He had memorized the main ideas so deeply and vividly that the entire hour was lived in these alone; often he took little notice of the textbook over which he was lecturing.³⁵

Kant would bring his copy of the required textbook with him to class³⁶ and sometimes notes on loose sheets of paper, although many of his textbooks were bound with interleaved blank pages, giving ample room for writing down his notes, and over the years these pages were entirely filled, yet he rarely read from these notes or the textbook, instead engaging the author in a conversation and using the text as an organizing principle and as a springboard for his own ideas.

We have more reports of the lectures in his later years, and these were mixed. C. F.

Reusch, a son of the physics professor, attended Kant’s lectures in the mid-1790s: To a young man of 15-16 years under those circumstances, not much of his philosophical lectures could be put into a context that made them understandable; what I grasped was an occasional illuminating point or spark in the soul. I don’t believe that it went any better at that time with the older students. In contrast, his physical geography lectures were quite understandable, even highly intellectually stimulating and entertaining.³⁷

Another student from the same period, an Austrian nobleman by the name of W. J. G. von Purgstall (1773-1812), wrote that Kant’s “presentation is entirely in the tone of ordinary speech and, if you will, not very beautiful. … Yet even though he does not look all that great, even though his voice is unclear, everything that his delivery lacks in form is richly replaced by the excellence of the content,” and then adds how helpful Kant’s lectures were for understanding his published works: One never leaves his auditorium without bringing home some elucidating hint into his writings, and it is as though one arrived at the easiest and shortest way to understanding many difficult sentences in the Critiques of Pure and Practical Reason. … [H]e simply enters directly into the subject and talks about it as though he would never dream the materials could be very difficult, and wholly convinced that anyone could understand it.³⁸

Kant often chose a student from the audience to look in the eye while lecturing, using this as a gauge of how well he was being understood. He must have found many of those eyes discouraging. Borowski studied with him during his earliest years and noted that “a lively attentiveness was always required. Without this his lectures couldn’t be understood, and one would get lost.”³⁹ Kant was generally hard to understand – in content, and sometimes in delivery – and students were advised to take his easier classes first (physical geography, anthropology, moral philosophy) or else begin with an easier professor.⁴⁰

Kant’s lectures and his students

Two things fill the mind with ever new and increasing admiration and reverence, the more often and more steadily one reflects on them: the starry heavens above me and the moral law within me. (CPrR 5:161)

Kant’s philosophical project, broadly understood, was to reconcile the physical and moral worlds – the world of Newtonian mechanics with the world of persons – and doing this required some hard and innovative work in metaphysics. The lines quoted above, and found on a plaque once adorning Kant’s tomb in Königsberg, come from the end of his Critique of Practical Reason (1788). The passage continues: I do not need to search for them and merely conjecture them as though they were veiled in obscurity or in the transcendent region beyond my horizon; I see them before me and connect them immediately with the consciousness of my existence. (CPrR 5:161-62)

These two worlds were basic facts for Kant and were captured by the names of Newton and Rousseau. Kant encountered Newton while still a teenager in Knutzen’s lecture hall; he read Rousseau twenty years later in the early 1760s, and this second encounter was just as transformative as the first. Rousseau was for Kant a second Newton, as suggested in a remark written into his copy of Observations on the Feeling of the Beautiful and Sublime (1764): Newton saw for the first time order and regularity combined with great simplicity, where before him was found disorder and barely paired multiplicity; and since then comets run in geometrical courses. Rousseau discovered for the first time beneath the multiplicity of forms human beings have taken on their deeply buried nature and the hidden law by the observation of which providence is justified. … After Newton and Rousseau, God is justified. … (OBS_n 9 [Ak 20:58-59])

Another remark suggests how Rousseau transformed Kant’s moral landscape: I feel a complete thirst for knowledge and an eager unrest to go further. … There was a time when I believed that this alone could constitute the honor of mankind, and I had contempt for the rabble who know nothing. Rousseau brought me around. This blinding superiority disappeared, I learned to honor human beings. … (OBS_n 7 [Ak 20:43-44])

Unfortunately, these two worlds – Newton’s physical world of material bodies understood with and governed by causal laws, and Rousseau’s moral world in which each human, as a free and rational being, is of inestimable worth living in a community of equals – are not easily held together. For how is freedom possible in Newton’s universe? And without freedom, what becomes of the moral universe? If every event in the physical universe is the direct result of one or more previous events, then every event happens necessarily and human freedom is an illusion. The laws of nature appeared to leave no room for the concerns of morality and the freedom it assumes.⁴¹

That was one puzzle confronting Kant. A second puzzle arrived at about the same time in the form of David Hume, who famously argued that physical causation is nothing more than a subjective sense of connection between two events based on regularities encountered in the past, and that there is no objectively necessary connection between these events, which are themselves entirely “loose and separate.”⁴² Kant viewed this as a serious problem for the natural sciences, as these are meant to be systems of objective and necessary causal laws. But if Hume is correct, such laws are merely contingent empirical generalizations.

Kant’s intellectual life has traditionally been understood as falling into two periods – the pre-critical and the critical – with the publication of his Critique of Pure Reason (1781) marking the divide. These two puzzles fell on the pre-critical side, and their solution marked the divide. The metaphysical doctrine providing the solution, and which defined his new “critical philosophy,” was what Kant called transcendental idealism, which holds that knowledge is possible only when the mind partly constitutes the thing being known.

Kant arrived at transcendental idealism by asking a deceptively simple question: “How is experience of an objective, public world possible?” He concluded that this requires the mind to structure the experienced world: first, by the sensibility passively receiving and shaping (as spatiotemporal) an unknowable given, and second, by the understanding actively structuring this spatiotemporal array into the world of physical objects. The mind is no longer a passive recipient of sensations, but instead actively structures those sensations into an objective world, and each mind does this, and does this in the same way, resulting in a public, shared world.

Transcendental idealism redraws the boundary between the knowing subject and the known object and, like any boundary, it has two sides, one humbling and one affirming. The humbling side limits our knowledge claims to the world of appearances (the phenomenal world), denying that we are capable of speculative insight into reality, thus humbling traditional metaphysics into silence. The affirming side reminds us that this phenomenal world that we can know just is, after all, the spatiotemporal world of material objects in which we live and play and pursue science. What is more, transcendental idealism shows us that at least some propositions about this world are a priori knowable, namely, the formal part contributed by the knowing self. We cannot have a priori knowledge of any particular causal laws, but we can know a priori that such laws exist to be discovered empirically. Thus Kant’s two puzzles are solved, for although the phenomenal world is entirely law-governed by causal relations, it is at least possible that there exists a noumenal (real) self that is free and thus that morality is possible.

In planning out his new system, Kant had imagined writing a methodological propaedeutic (which turned into the Critique of Pure Reason) followed by a metaphysics of nature and a metaphysics of morality.⁴³ The former appeared in 1786 as the Metaphysical Foundations of Natural Science (MFS 4:467-565), while the latter did not appear until 1797 as the two-part Metaphysics of Morals (MM 6:205-355, 373-493): the Doctrine of Right (concerning the nature of law and the state) and the Doctrine of Virtue (concerning the system of moral duties that bind individuals). Kant’s best known and most closely studied work on moral philosophy was also the first that he published: the relatively short Groundwork of the Metaphysics of Morals (1785; G 4:387-463), in which he introduced the concept of the categorical imperative and made autonomy a central feature of how we understand morality.

Responses to the Critique

Kant’s new critical philosophy did not enjoy a promising start.⁴⁴ The Critique of Pure Reason is a hard read today and it was perhaps just as hard for those living in Kant’s day and speaking his language. Some of the brightest minds, such as Moses Mendelssohn and Johann Wolfgang von Goethe, complained in all sincerity that they could not make sense of it.

This poor reception helped motivate Kant to write a summary introduction, the Prolegomena to Any Future Metaphysics (1783; Pro 4:255-383), which was further shaped by an early anonymous review written by the popular philosopher Christian Garve (and heavily edited by J. G. H. Feder), which viewed the Critique as belonging to the tradition of Humean skepticism and Berkeleyan idealism.⁴⁵ While Kant had only respectful words for Hume’s work, he wished to sharply distinguish his own brand of idealism from what he called the “dogmatic idealism” of George Berkeley, and several additions in the 1787 second edition of the Critique, such as the “Refutation of Idealism,” were responding to the Garve/Feder review.

Not until K. L. Reinhold’s Letters on the Kantian Philosophy (1786-87)⁴⁶ did the Critique begin to receive its proper audience, and camps soon formed of Kantians and anti-Kantians. C. G. Schütz and Gottlieb Hufeland’s Allgemeine Literatur-Zeitung (1785-1804), a daily newspaper from Jena featuring book reviews, provided an early sympathetic forum for the new Kantian philosophy, while the Wolffian J. E. Eberhard published the Philosophisches Magazin (1788-92), featuring articles critical of Kant and in which Eberhard himself argued that Kant’s “new” philosophy was, at best, a rehashing of Leibniz and Wolff.⁴⁷ Kant spent the 1780s and 1790s filling out his critical philosophy and responding to critics, for which he often enlisted the aid of colleagues. Of these, most notable was Johann Schultz (1739-1805), a mathematics professor at Königsberg, whose review of Kant’s 1770 Dissertation was found by Kant to be so insightful that he later asked for Schultz’s help in promoting the Critique of Pure Reason. In 1797 Kant publicly declared Schultz to be his most reliable expositor.⁴⁸ Not even Schultz was a blind follower, however, and problems he raised in 1785 with what is commonly viewed as a key section of the Critique of Pure Reason, namely, the Transcendental Deduction, nearly led to a falling out with Kant, but also encouraged him to revise that section heavily for the second edition.⁴⁹

Kant’s watch, Mr. Green, and the art of conversation

The best known Kant anecdote comes from Heinrich Heine, who began by noting that “the life story of Immanuel Kant is difficult to describe, because he had neither a life nor a story”: He lived a mechanically ordered, almost abstract bachelor existence in a quiet isolated lane in Königsberg, an old city on the northeastern border of Germany. In my opinion, not even the great cathedral clock there went about its daily labor with less passion and more regularity that its compatriot Immanuel Kant. Getting up, drinking coffee, writing, giving lectures, eating, walking: everything had its set time, and the neighbors knew that it was exactly half past three when Immanuel Kant, in his grey frock-coat, rattan cane in hand, emerged from his front door and strolled in the direction of small Lindenallee, which is still called “Philosopher’s Way” on his account.⁵⁰ Another anecdote – likely from the late 1780s or early ’90s – also involved Kant and a clock, this time his own watch to which he had attached an amber pendant containing an ancient fly. During a discussion with friends about past geological epochs, Kant lifted up his watch and said to the fly: “How great our knowledge of [those epochs] would be, if only you could tell us how things were in your time.”⁵¹

The amber pendant may have been nothing more than an innocent decoration, but the symbolism is significant enough, as is the watch itself, given Heine’s description of Kant’s clock-like existence. But Kant had not always been like that, and any truth to Heine’s caricature can be attributed to Kant’s association with his good friend Mr. Green, who was, in an allegorical sense, Kant’s second watch.

Joseph Green (1727-86) was an English merchant who had been living in Königsberg for a number of years before he met Kant and, according to Jachmann, quite by chance, at least by the summer of 1763 (a “Friendship Glass” with both their names bears the date of 30 August 1763). This first encounter involved a group discussing the conflict between Britain and the Americans, with Kant vigorously defending the Americans and roundly condemning the British, all of which became too much for Green who challenged Kant to a duel. Things might have gone badly had not Kant explained his position so dispassionately and convincingly that Green was not only pacified but also charmed, and the two strolled off together as friends.⁵²

The two bachelors remained close until Green’s death twenty years later, with Kant regularly taking his meals at Green’s house. It was from Green that Kant developed his later penchant for strict routine and for living one’s life according to maxims, and their common acquaintance, T. G. von Hippel, the Königsberg mayor, featured Green in his anonymous play, The Man Who Lived by the Clock.⁵³ Whatever truth there is in Heine’s famous image of Kant’s “mechanically-ordered life” appears to have stemmed from this association with Green.

At least by the 1780s⁵⁴ Kant was spending nearly every evening at Green’s, returning home at seven, except on Saturdays, when he left at nine. They were not dining alone, however, at least not usually. Jachmann described the rhythm of these evening gatherings: Kant went to Green’s every afternoon to find him asleep in his armchair. Kant would sit down, meditate for a while and also fall asleep; the bank director Ruffmann would usually come along and do the same, until finally Motherby would arrive in the room at a certain hour and wake up the party, which would then converse over the most interesting topics until seven o’clock.⁵⁵ Kant made many new acquaintances there, including Green’s younger business partner, Robert Motherby (1736-1801), and Kant eventually found himself spending every Sunday (along with Green) in the Motherby home, where Kant would play with the children.⁵⁶

Green was companionable, well-regulated, and clearly possessed of a good mind, as we are told that Kant had him read every line that went into the Critique of Pure Reason (1781).⁵⁷ Green’s death in 1786 was hard for Kant and appears to have marked his life in various ways. He gave up all evening commitments after that and confined himself to eating only a midday meal, which he now took in his own home purchased a few years earlier, and perhaps it was Green’s death that led Kant to have a kitchen installed in 1787 and to hire a cook, although he continued his pattern of dining at Motherby’s each Sunday.⁵⁸ For the first few years Kant’s younger colleague, C. J. Kraus, the full professor of practical philosophy, was a daily dinner guest, having agreed to split the costs with Kant.⁵⁹ Jachmann notes that there were usually one or two dinner companions, and at most five, since the table could seat no more than six.⁶⁰

Two memoirs – by Hasse (1804) and by Reusch (1848) – refer to Kant’s dinner parties in their titles, underscoring the centrality of this aspect of Kant’s life.⁶¹ Kant was above all else a social creature and a famous conversationalist, and several hours of each day were devoted to this practice, normally around the table. Abegg wrote that “Kant could sit at the table until seven or eight at night, so long as someone stayed to talk with him,”⁶² and all topics of conversation were open at dinner, except philosophy. An Austrian nobleman who studied Kant under Reinhold at Halle and then traveled to Königsberg in 1795 to attend Kant’s lectures on logic and physical geography, wrote that Kant invited me to lunch every fourth day, and I’ve accepted a few times. He has not yet spoken a word of theoretical philosophy, and I never try to bring it up, but always let him guide the conversation, and it seems that he does not enjoy discussing abstractions.⁶³

In the Anthropology from a Pragmatic Point of View (1798), Kant discusses the natural tension between pursuing the moral and the physical good. Balancing this tension is at the core of humanity, Kant argues, and nothing strikes the balance quite so well as a good dinner party: “The good living that still seems to harmonize best with true humanity is a good meal in good company” (An 7:278), and earlier in that text Kant noted that “[t]here is no situation in which sensibility and understanding unite in one enjoyment that can be continued as long and repeated with satisfaction as often as a good meal in good company” (An 7:242).

Kant loved to eat, but not alone – a practice “unhealthy for a scholar who philosophizes,” as one then foregoes the differing ideas that dinner companions provide (An 7:279-80). These dinners could be seen as examples of the public sphere where one follows the maxims of the sensus communis, namely to think for oneself (so that one might make a contribution to the conversation), to think from the perspective of everyone else, and to think consistently (CJ 5:294). Kant’s concern with the rules governing these dinners fell well beyond mere table etiquette. For instance, the number of guests was to be such as could support a single conversation – Kant recommended between three and nine – thus allowing each to talk to all (An 7:278-79); dogmatic assertions were discouraged (An 7:281); and the discussion was to be held in a spirit of trust and discretion (An 7:279) – all with an eye toward a free and open exchange of ideas.⁶⁴

In the early years, Kant dined in public inns when he lacked an invitation into someone’s home, but these invitations came frequently and from an impressive assortment of aristocrats, military officers, and government officials. Kant enjoyed a close relationship with the Keyserlings, especially with Countess Charlotte, who sat him on her right side so long as no visiting dignitary required that place of honor instead. Kant had a standing invitation to dinner at their palace every Tuesday, a tradition continuing until near her death in 1791.⁶⁵

When one reflects on Kant’s humble origins, it is remarkable how far he had come in polite society. His years tutoring in the von Hülsen family (c. 1751-53) were perhaps his first introduction to that society, after which his visits with the Keyserlings, beginning after his return to Königsberg in 1754, completed the education. The Russian occupation of Königsberg that soon followed (lasting between 1758-62)⁶⁶ opened up society and its dinners and dances to a wider range of citizens, with professors now mingling with the aristocratic and military classes. Kant thrived in this environment.

Completing the system: Kant’s third Critique

The Critique of the Power of Judgment (1790) was Kant’s most influential work for the generation of philosophers that followed, bringing to center stage the concepts of purpose and systematicity, and marking the emergence of aesthetics as a serious philosophical discipline. Kant himself gave the book a preeminence in his system, writing in the preface that “with this I bring my entire critical enterprise to an end” (CJ 5:170).

When Kant published the Critique of Pure Reason in 1781, he did not have in mind to write any more critiques: one was to be quite enough. But while working up the second edition of this Critique (published in 1787), the material that he was developing on practical reason – primarily his defense of God, freedom of the will, and the immortality of the soul as “postulates of practical reason” – expanded to the point that an entirely separate treatment was in order,⁶⁷ which he then published as the Critique of Practical Reason (1788; CPrR 5:1-164).

The origins of the third Critique are less straightforward, with the idea to write it falling hard on the heels of working out the second. A letter to C. G. Schütz in June 1787 (C 10:490) indicated Kant’s intentions, and six months later we find him writing in a letter to Reinhold: I am now at work on the critique of taste, and I have discovered a new sort of a priori principles. … For there are three faculties of the mind: the faculty of cognition, the faculty of feeling pleasure and displeasure, and the faculty of desire. … This systematicity put me on the path to recognizing the three parts of philosophy …: theoretical philosophy, teleology, and practical philosophy. … (C 10:514-15)

Teleological explanation, where one understands nature as a system of ends or purposes rather than as a large clockwork following Newtonian laws, had yet to be properly addressed by Kant. The structure of the third Critique strikes the casual reader as simply odd, for Kant appears to have published two books under a single cover: the first concerns aesthetics (the nature of the beautiful and the sublime, of genius, and of the moral dimensions of aesthetic judgment), while the second concerns primarily biology (the use of purpose or final causation in our explanation of living organisms, as well as the purpose of nature as a whole). What unites these two halves is the concept of purposiveness guiding judgment, whether that judgment is aesthetic or teleological. With aesthetic judgments, beautiful works of art or natural objects fill us with a disinterested pleasure suggesting a harmonious fit between the mind and the object contemplated; with teleological judgments of nature, organisms appear purposive in their growth and development.

With this third Critique, Kant intended to complete his critical project by bridging the “incalculable gulf fixed between the domain of the concept of nature, as the sensible, and the domain of the concept of freedom, as the supersensible” (CJ 5:175-76). He hoped to demonstrate the possibility of these two realms forming a coherent whole, and so to bring within a single focus the starry heavens above (the domain of nature as legislated a priori by the understanding) and the moral law within (the domain of freedom as legislated a priori by reason). Unifying theoretical and practical philosophy under a single principle or system was a preoccupation passed on to those following Kant.

Kant and religion

Prussia’s first patron of the Enlightenment, Friedrich the Great, died on August 17, 1786, and was succeeded by his religiously conservative nephew, Friedrich Wilhelm II. Kant’s long-time admirer and ally at the Berlin court, K. A. von Zedlitz, was eventually replaced as Minister of Education and Religious Affairs by J. C. Wöllner – the man whom Friedrich the Great had described as “a deceitful and intriguing parson” – and after just one week in office, on July 9, 1788, Wöllner issued a religious edict aimed at suppressing the display of Enlightenment beliefs among teachers and clerics, followed in December by a censorship edict to exert more control over religious publications. Kant himself was reprimanded on October 1, 1794, for his publication the previous year of Religion within the Boundaries of Mere Reason (1793; Rel 6:1-202), and perhaps also for his more recent essay “The End of All Things” (1794; EAT 8:327-39) that satirized the government censors. Kant was forbidden to teach or write on matters of religion because he had, in the words of the cabinet order, misused his philosophy “to distort and disparage many of the cardinal and foundational teachings of the Holy Scriptures and of Christianity” (Ak 11:525). Kant responded to the Berlin government on Sunday, October 12, the day before the beginning of the winter semester, writing that he would forgo any further public discussion of religion, both in lecture and in publications (C 11:525-26, 530), a pledge that he is said to have kept until the death of Friedrich Wilhelm II in 1797.⁶⁸

Kant’s early life had been deeply informed by religion, and he remained steadily engaged with religious questions until the very end. In his publications, beginning with his New Elucidation (1755) and The Only Possible Argument in Support of a Demonstration of the Existence of God (1763), he criticized the ontological proofs found in Descartes and Wolff, but then developed a proof based on the necessary conditions for the possibility of existence in general. By the time of his critical writings, however, Kant was quite certain that all such proofs for God’s existence fail and that the scope of natural theology was rather narrow. In general, religious doctrine is beyond the domain of human knowledge, incapable of either proof or disproof, but since certain supersensible ideas – including God, the afterlife, and freedom of the will – have important practical implications for us, Kant found it important “to deny knowledge in order to make room for faith” (Bxxx).

In sum, the purpose of religion is to bolster our moral lives in community by helping to make actual the moral kingdom of ends (see, for instance, Rel 6:97-99). At the same time, any religion demanding assent to a creed is an affront to our humanity and a breeding ground for hypocrites. In a letter of April 28, 1775, to the Swiss theologian J. C. Lavater (1741-1801), Kant wrote:

You ask for my opinion of your discussion of faith and prayer. Do you realize whom you are asking? A man who believes that, in the final moment, only the purest candor concerning our most hidden inner convictions can stand the test and who, like Job, takes it to be a crime to flatter God and make inner confessions, perhaps forced out by fear, that fail to agree with what we freely believe. I distinguish the teachings of Christ from the report we have of those teachings. In order that the former may be seen in their purity, I seek above all to separate out the moral teachings from all the dogmas of the New Testament.(C 10:175-76)

As for special revelation, Kant rejected from the very start any use of it to explain physical phenomena, and eventually of morality as well. His Universal Natural History and Theory of the Heavens (1755) offered an account of the universe’s design based strictly on Newtonian mechanics. In addition, his three earthquake essays of 1756⁶⁹ sought to dissuade his readers from viewing the Lisbon earthquake, and earthquakes in general, as anything more than physical events. They are neither punishments meted out by an angry god nor do they offer any clues about God’s nature or existence. Kant had little patience for claims of special revelation, which he found deeply problematic – for by what criterion could we ever be certain that some event had a divine origin, much less what it might mean? One special revelation considered central to Judaism, Christianity, and Islam – namely, God’s command that Abraham sacrifice his son Isaac – was singled out for special scorn in his Conflict of the Faculties (1798):

For if God should really speak to a human being, the latter could still never know that it was God speaking. It is quite impossible for a human being to apprehend the infinite by his senses, distinguish it from sensible beings, and be acquainted with it as such. – But in some cases the human being can be sure that the voice he hears is not God’s; for if the voice commands him to do something contrary to the moral law, then no matter how majestic the apparition may be, and no matter how it may seem to surpass the whole of nature, he must consider it an illusion. (CF 7:63) [Here Kant adds a note:] We can use, as an example, the myth of the sacrifice that Abraham was going to make by butchering and burning his only son at God’s command (the poor child, without knowing it, even brought the wood for the fire). Abraham should have replied to this supposedly divine voice: “That I ought not to kill my good son is quite certain. But that you, this apparition, are God – of that I am not certain, and never can be, not even if this voice rings down to me from (visible) heaven.” (CF 7:63n)

Personally, Kant appears to have had little use for organized religion, and perhaps just as little for a personal god. As an adult he rarely passed through a church door,⁷⁰ and when a friend asked Kant near the end of his life what he thought about an afterlife, Kant replied: “Nothing certain.”⁷¹ Johann Brahl, a frequent dinner guest and longtime editor of the Hartung newspaper, noted in 1798 that, “while Kant postulates God, he does not himself believe in it,” nor does he fear death.⁷²

Kant’s end

Two stories have come down to us of how Kant might have died, but did not; and in both cases someone had thought to murder him during one of his regular afternoon walks. The first involved a deranged butcher, whom Kant skillfully talked down. The second involved an escaped prisoner who resolved to shoot dead the first person he met, which turned out to be Kant on his walk, but the sight of the elderly professor so moved the convict that he instead shot a young boy who happened by.⁷³ As it turns out, Kant died peacefully in his own bed, just a month shy of his eightieth birthday, on February 12, 1804 – although for all practical purposes he had disappeared sometime the previous year. In both body and mind, by the end Kant was an entirely wasted man.

A number of publications appeared under Kant’s name during his last years. The occasional pieces were no more than a few paragraphs in length: a short preface to R. B. Jachmann’s book on religion (1800; Ak 8:441), an afterword for a German-Lithuanian dictionary (1800; Ak 8:445), a public notice denouncing Fichte’s philosophical innovations (1799; C 12:370-71), and another denouncing Gottfried Vollmer’s unauthorized publication of Kant’s physical geography lectures (1801; Ak 12:372). Younger colleagues edited three volumes from manuscripts – G. B. Jäsche’s Logic (1800; JL 9:1-150), and F. T. Rink’s Physical Geography (1802; PG 9:151-436)and Pedagogy (1803; LP 9:439-99) – but Kant had no hand in any ofthese.

Kant was buried on February 28, 1804, just north of the church where he had been baptized eighty years earlier.  Wasianski had been present at his death and filed this last report: “the mechanism faltered and the machine stopped moving.”⁷⁴

Notes

1. I have drawn primarily from the following early sources: Johann Christoph Mortzfeld, Fragmente aus Kants Leben. Ein biographischer Versuch (Königsberg: Hering und Haberland, 1802); Ludwig Ernst Borowski, Darstellung des Lebens und Charakters Immanuel Kants, Von Kant selbst genau revidirt und berichtigt (Königsberg: Nicolovius, 1804); Reinhold Bernard Jachmann, Immanuel Kant geschildert in Briefen an einen Freund (Königsberg: Nicolovius, 1804); Ehregott Andreas Christoph Wasianski, Immanuel Kant in seinen letzten Lebensjahren. Ein Beitrag zur Kenntnis seines Charakters und häuslichen Lebens aus dem täglichen Umgange mit ihm (Königsberg: Nicolovius, 1804); Johann Gottfried Hasse, Letzte Äusserungen Kants von einem seiner Tischgenossen (Königsberg: Nicolovius, 1804); Friedrich Theodor Rink, Ansichten aus Immanuel Kants Leben (Königsberg: Goebbels und Unzer, 1805); and material gathered in 1804 for Samuel Gottlieb Wald’s memorial address for Kant, but first published in Rudolf Reicke, Kantiana. Beiträge zu Immanuel Kants Leben und Schriften (Königsberg: Theile, 1860). Emil Arnoldt assessed the above and other material in his “Kants Jugend und die fünf ersten Jahre seiner Privatdocentur,” Altpreussische Monatsschrift 18 (1881): 606-86. Still definitive is Karl Vorländer, Immanuel Kant, der Mann und das Werk, 2 vols. (Leipzig: Meiner, 1924); and the more recent (and in English) Manfred Kuehn, Kant: A Biography (Cambridge: Cambridge University Press, 2001), both of which I have made constant use. Finally, an excellent brief developmental summary of Kant’s writings can be found in Paul Guyer, Kant (London: Routledge, 2006), ch. 1.  An earlier version of the present essay appeared in The Palgrave Kant Handbook, edited by Matthew C. Altman (Palgrave Macmillan, 2017), pp. 21-47.
2. Vorländer, Immanuel Kant, 2:385. The Kant family papers are printed in Arnoldt, “Kants Jugend,” 608.
3. Johann Friedrich Goldbeck, Nachrichten von der Königlichen Universität zu Königsberg in Preußen, und den daselbst befindlichen Lehr- Schul- und Erzeihungsanstalten (Leipzig: Buchhandlung der Gelehrten, 1782), 254-55; and Fritz Gause, Die Geschichte der Stadt Königsberg in Preussen, 2nd ed. (Köln: Böhlau, 1996), 2:126.
4. Vorländer, Immanuel Kant, 1:20-21.
5. Borowski claims that Kant hoped to erect a monument in Schultz’s honor; see his biography (Darstellung, 152) and his notes for Wald (quoted in Reicke, Kantiana, 31). In the latter he refers to Schultz as one of Kant’s valued teachers at the Collegium Fridericianum, alongside Kant’s Latin teacher, Johann Friedrich Heydenreich.
6. Reported by Theodor Gottlieb von Hippel in his autobiography and reprinted in Friedrich Schlichtegroll, Biographie des Königl. Preuß. Gehimenkriegsraths zu Königsberg, Theodor Gottlieb von Hippel, zum Theil von ihm selbst verfaßt (Gotha: Perthes, 1801), 78-79.
7. On Kant’s experiences here, see Heiner F. Klemme, Die Schule Immanuel Kants. Mit dem Text von Friedrich Schiffert über das Königsberger Collegium Fridericianum, 1741 (Hamburg: Meiner, 1994), esp. 32-60.
8. Wald, quoted in Reicke, Kantiana, 6.
9. Borowski, Darstellung, 161-62.
10. Isaiah Berlin, Three Critics of the Enlightenment: Vico, Hamann, Herder, ed. Henry Hardy (Princeton: Princeton University Press, 2000), 258.
11. Lewis White Beck, Early German Philosophy: Kant and His Predecessors (Cambridge: Harvard University Press, 1969), 258-59.
12. Wald, quoted in Reicke, Kantiana, 6; a nearly verbatim quote is given by Hippel in Schlichtegroll, Hippel, 160.
13. Hippel, quoted in Schlichtegroll, Hippel, 162.
14. Benno Erdmann, Martin Knutzen und seine Zeit: Ein Beitrag zur Geschichte der Wolfischen Schule und insbesondere zur Entwicklungsgeschichte Kants (Leipzig: Voss, 1876), 116.
15. Arthur Warda, “Ergänzungen zu E. Fromms zweitem und drittem Beitrage zur Lebensgeschichte Kants,” Altpreussische Monatsschrift 38 (1901): 402.
16. Heilsberg, quoted in Reicke, Kantiana, 48.
17. Ibid., 49.
18. Ibid., 48; and Borowski, Darstellung, 28. See also Manfred Kuehn, “Kant’s Teachers in the Exact Sciences,” in Kant and the Sciences, ed. Eric Watkins (Oxford: Oxford University Press, 2001), 11-30.
19. Rink, Ansichten, 27.
20. Borowski, Darstellung, 28, 29, 163-64. See also Jachmann, Immanuel Kant, 10; and C. J. Kraus, quoted in Reicke, Kantiana, 7.
21. See Hans-Joachim Waschkies, Physik und Physikotheologie des jungen Kant. Die Vorgeschichte seiner Allgemeinen Naturgeschichte und Theorie des Himmels (Amsterdam: Grüner, 1987), 20n4.
22. Both Erdmann (Martin Knutzen) and Waschkies (Physik und Physikotheologie) promote the view of a close relationship between Knutzen and Kant. A more skeptical position is found in Kuehn, Kant, 78-84; and Kuehn, “Kant’s Teachers,” 22-23.
23. From a recently discovered reflection of Kant’s, reproduced in Steve Naragon and Werner Stark, “Ein Geschenk für Rose Burger. Notizen und Hinweise zu einem neu aufgefundenen Kant-Blatt,” Kant-Studien 104, no. 1 (March 2013): 5. In the context of discussing Kant’s logic lectures, Jachmann wrote that “it was never his intention merely to recite a logic to his listeners, but rather to teach them to think” (Immanuel Kant, 28-29). See also the Dohna logic lectures of 1792: “Not to learn philosophy – but rather to learn to philosophize, otherwise it remains only imitation …” (DWL 24:698). See also Kant’s discussion of the “zetetic method” of the Announcement (1765; APL 2:307).
24. Borowski, Darstellung, 84, 188. The same sentiment is found in Kant’s essay “An Answer to the Question: What Is Enlightenment?” (1784; WE 8:35), and at the end of “What Does It Mean to Orient Oneself in Thinking?” (1786): “Thinking for oneself means seeking the supreme touchstone of truth in oneself (i.e. in one’s own reason); and the maxim of always thinking for oneself is enlightenment” (OT 8:146n).
25. Most universities were arranged with four faculties: philosophy, plus the three higher faculties of theology, law, and medicine. Graduation was possible from any of them. A graduate of the philosophy faculty became a Doctoris Philosophiae seu Magistri – a “doctor of philosophy or magister,” although he was commonly called a “Magister” (designated by an ‘M.’ printed before one’s name) and a graduate from any of the higher faculties was called a “Doctor” (designated by a ‘D.’ printed before one’s name). The words themselves are nearly synonymous: a magister is one who teaches, and a doctor is one who has been taught.
26. Waschkies, Physik und Physikotheologie, 25-27, offers the best evidence for this disputed date of Kant’s departure. This early chronology is contested. For an account, see “The Hofmeister” at www.manchester.edu/kant/Students/studentHofmeister.htm.
27. Bernard Haagen, “Auf den Spuren Kants in Judtschen. Ein Beitrag zur Lebensgeschichte des Philosophen,” Altpreußische Monatsschrift 48 (1911): 382-411, 528-56; at 390.
28. This matter had already been resolved by Jean le Rond d’Alembert in 1743, although Kant had not heard the news, which presumably had not yet reached Königsberg.
29. Kant was also studying the work of academics such as Wolff, who taught at Halle and Marburg, and Crusius, who taught at Leipzig. But Lambert and Maupertuis were outside the university, as was Euler (other than for a brief stint at St. Petersburg). Hume and Rousseau were non-academics, but Kant did not read them until later.
30. Johann Friedrich Goldbeck, Nachrichten von der Königlichen Universität zu Königsberg in Preußen, und den daselbst befindlichen Lehr- Schul- und Erzeihungsanstalten (Leipzig: Buchhandlung der Gelehrten, 1782), 102, estimates student living expenses (room, board, and firewood) at sixty thaler per year, so these tuition fees for private lectures were not trivial. For comparison, Kant’s starting annual professor’s salary in 1770 was 166 2/3 thaler; see the Cabinet order from King Friedrich II of March 31, 1770 (reprinted at Ak 10:94).
31. F. J. Buck held the logic/metaphysics position – he had been preferred over Kant in 1759 when J. D. Kypke’s death made available the position – and Kant petitioned the government to give the vacant mathematics chair to either K. A. Christiani (1707-80), the current professor of moral philosophy, or to Buck, with the resulting vacancy to go to Kant. The king chose the latter course, but it appears from his letter that Kant would have been equally comfortable assuming either chair (moral philosophy or logic/metaphysics).
32. Most of the data regarding Kant’s teaching comes from Emil Arnoldt, Gesammelte Schriften, ed. Otto Schöndörffer, 10 vols. (Berlin: Cassirer, 1906-11), vols. 4-5.
33. This was an introductory course that surveyed the philosophical disciplines (logic, metaphysics, practical philosophy) and their history.
34. Franz Eulenburg, Die Frequenz der deutschen Universitäten von ihrer Gründung bis zur Gegenwart (Leipzig: Teubner, 1904), 296.
35. Jensch, quoted in Johann Friedrich Abegg, Reisetagebuch von 1798 (Frankfurt: Insel, 1976), 251.
36. By government decree, professors had to use an approved textbook in each of their courses. Purgstall describes the tattered condition of Kant’s copy of Meier’s logic text (this was near the very end of Kant’s teaching career): “He always brings the book along. It looks so old and soiled, I believe that he has brought it daily to class with him for forty years. All the blank leaves are covered with writing in a small hand, and besides, many of the printed pages have leaves pasted on them, and lines are frequently crossed out, so that, as you might imagine, scarcely anything of Meyer’s Logic is left.” Even by the early 1760s, Jensch reported that Kant’s copy of Baumgarten’s Metaphysica was “covered with notes all over” (Karl Hugelmann, “Ein Brief über Kant,” Altpreussische Monatsschrift 16 [1879]: 608-9).
37. Christian Friedrich Reusch, Kant und seine Tischgenossen. Aus dem Nachlaß des jüngsten derselben, des Geh. Ob.-Reg.-Rats Dr. Chr. F. Reusch (Königsberg: Tag & Koch, 1848), 291-92.
38. From a letter written by Purgstall and quoted in Hugelmann, “Ein Brief über Kant,” 608-9.
39. Borowski, Darstellung, 85, 185-86.
40. Wald, quoted in Reicke, Kantiana, 18. Hippel, who matriculated at the university in 1756, wrote that he took the less challenging courses from Buck before attending Kant’s lectures (Hippels sämmtliche Werke, vol. 12: Hippels Leben, ed. Gottlieb Hippel [Berlin: Reimer, 1835], 91). Kant was aware of these difficulties and encouraged students to attend K. L. Pörschke’s lectures first in preparation (Jachmann, Immanuel Kant, 30).
41. Ten years earlier, Kant considered a similar challenge – this time from the side of Wolffian rationalism. In A New Elucidation of the First Principles of Metaphysical Cognition (1755; NE 1:387-416), Kant addressed this conflict between rationalism and human freedom, but at the time sided with Wolff over Crusius’s “liberty of indifference” (NE 1:398-405). Kant eventually abandoned the rationalist account of freedom – calling it “the freedom of a turnspit” in his Critique of Practical Reason (CPrR 5:97).
42. David Hume, Philosophical Essays Concerning Human Understanding [later editions: An Enquiry Concerning Human Understanding] (London: Millar, 1748), sect. 7 (“Of the Idea of Necessary Connection”), pt. 2. Kant first raised this worry about causal connection in his essay Attempt to Introduce the Concept of Negative Magnitudes into Philosophy (1763; ANM 2:167204): “I fully understand how a consequence is posited by a ground in accordance with the rule of identity: analysis of the concepts shows that the consequence is contained in the ground. … But what I should dearly like to have distinctly explained to me, however, is how one thing issues from another thing, though not by means of the law of identity” (ANM 2:202).
43. An early version of this plan can be found in Kant’s letter to J. H. Lambert (December 31, 1765) (C 10:56).
44. Apart from Kuehn’s biography (Kant), see also Manfred Kuehn, “Kant’s Critical Philosophy and Its Reception – the First Five Years (1781-1786),” in The Cambridge Companion to Kant and Modern Philosophy, ed. Paul Guyer (Cambridge: Cambridge University Press, 2006), 63063; Karl Ameriks, Kant and the Fate of Autonomy: Problems in the Appropriation of the Critical Philosophy (Cambridge: Cambridge University Press, 2000); Brigitte Sassen, Kant’s Early Critics: The Empiricist Critique of the Theoretical Philosophy (Cambridge: Cambridge University Press, 2000); and Frederick C. Beiser, The Fate of Reason: German Philosophy from Kant to Fichte (Cambridge: Harvard University Press, 1987).
45. Published in the January 19, 1782 issue of the Göttingen Gelehrten Anzeigen.
46. Reinhold published his letters in installments in C. M. Wieland’s Teutsche Merkur (August 1786 to October 1787), and Kant publicly thanked Reinhold in “On the Use of Teleological Principles in Philosophy” (1788; TelP 8:160, 184).
47. Kant replied to Eberhard with “On a Discovery whereby Any New Critique of Pure Reason Is to Be Made Superfluous by an Older One” (1790; NCR 8:187-251), and also enlisted his colleague Johann Schultz to critically review Eberhard’s magazine.
48. Kant, “Against Schlettwein” (1797; Ak 12:367-68). See Johann Schultz, Erläuterungen über des Herrn Professor Kant Critik der reinen Vernunft (Königsberg: Dengel, 1784); and Johann Schultz, Prüfung der Kantischen Critik der reinen Vernunft, 2 vols. (Königsberg: Hartung, 1789).
49. Schultz’s criticisms are found in his anonymous review of J. A. H. Ulrich, Institutiones logicae et metaphysicae scholae suae scripsit (Jena: Cröker, 1785), in Allgemeine LiteraturZeitung (December 13, 1785), 247-49, translated into English in Sassen, Kant’s Early Critics, 210-14. See also Kant’s Metaphysical Foundations of Natural Science (1786; MFS 4:467-565), where he publicly answers Schultz, in part by demoting the Transcendental Deduction’s role (MFS 4:474-76).
50. Heinrich Heine, On the History of Religion and Philosophy in Germany and Other Writings, ed. Terry Pinkard, trans. Howard Pollack-Milgate (Cambridge: Cambridge University Press, 2007), 79. The claim that housewives set their clocks to Kant’s passing was likely inspired by Jachmann’s account of the evenings Kant would spend at Green’s house, which always ended at the same time: “The group always disbanded so punctually at 7 o’clock that I often heard the neighbors on the street say: It can’t yet be seven, since Professor Kant has yet to pass by” (Immanuel Kant, 81-82). Heine’s claim regarding the name of the walk sounds likely, but is false, as it bore that name long before Kant ever walked there; see Christopher Hartknoch, Alt- und Neues Preussen, oder Preüssischer Historien (Frankfurt & Leipzig: Hallervorden, 1684), 395.
51. Karl Gottfried Hagen, “Bemerkungen, die Entstehung des Bernsteins betreffend,” in Beiträge zur Kunde Preußens, 8 vols. (Königsberg, 1821), 4:207-27; the Kant anecdote is in a note on p. 209. Jachmann (Immanuel Kant, 147) mentions Hagen as one of Kant’s regular dinner guests. A photograph of presumably the same watch was published in a German newspaper sometime after 1933, although the amber pendant appears to have gone missing. The source of the clipping is unknown, but it was reproduced in Lorenz Grimoni and Martina Will, eds., Immanuel Kant: Erkenntnis – Freiheit – Frieden (Husum: Husum, 2004), 183.
52. Jachmann’s account (Immanuel Kant, 1804, 77-79), written in 1804 or earlier, describes the argument between Kant and Green as concerning the “English-North American War” and the conflict between the English and the Americans.  August Hagen, who as a young boy would have met Kant, but whose information would have been second-hand from older family and friends, also re-tells this story (“Kantiana,” Neue Preußische Provinzial-Blätter 6 [1848]: 8), describing the conflict between England and the “North Americans who broke away form the motherland.” Most modern readers would see no inconsistency between Jachmann’s and Hagen’s accounts, but as Gerfried Horst has recently pointed out (“Immanuel Kant, Joseph Green, Robert Motherby and the Americans,” 2021 [online at: www.freunde-kants.com/kantgreen-motherby-eng]), an ‘American’ in Kant’s lexicon was a Native American, not a European colonist.  Kant was quite consistent in this usage throughout his career and Jachmann, who studied with Kant and otherwise spent many years in conversation with him, would have most likely adopted this usage as well.  What this means is that the war Jachmann mentions was not the American Revolutionary War (1775-1783), which was in any event too late for a “first meeting” between Kant and Green, but rather the French and Indian Wars in North America that began in 1754 and were an early phase of the Seven Years War (1756-63) centered in Europe and which resulted in the Russian occupation of Königsberg (January 1758 to July 1762).  
53. Der Mann nach der Uhr, oder der ordentliche Mann, published in 1765, first performed in Hamburg the following year (Hagen, “Kantiana,” 9-10). Jachmann, as well as Hagen, draws this connection to Green (Immanuel Kant, 80).
54. As suggested by Hamann’s correspondence (quoted in Vorländer, Immanuel Kant, 2:28). C. J. Kraus also notes that the daily gatherings occurred in later years, when Green’s gout prevented him from leaving his house easily (Reicke, Kantiana, 60).
55. Jachmann, Immanuel Kant, 81.
56. Borowski, Darstellung, 102; and Jachmann, Immanuel Kant, 51-52, 145, 148. The Motherbys had eleven children in all. Jachmann later served as a tutor to one of the sons, William Motherby, who attended Kant’s lectures in the early 1790s and later distinguished himself as a physician.
57. Jachmann, Immanuel Kant, 80.
58. Earlier, in the 1760s, Kant seems to have spent many of his Sundays just north of the city in Moditten with the head forester Michael Wobser. This is where Kant stayed for a few weeks in 1763 while composing Observations on the Feeling of the Beautiful and Sublime; see Dr. Michelis, “Kant – Hauslehrer in Judtschen?” Kant-Studien 38, nos. 1-2 (Jan. 1933): 492-93.
59. This arrangement came to an end around 1789 after a falling out between the two men, on which see Kuehn, Kant, 331-34. Kant continued with his dinners, of course, only without Kraus, and when they were both invited to someone else’s home, “they never sat right next to each other, but also not very far from each other” (Abegg, Reisetagebuch, 255-56).
60. Jachmann, Immanuel Kant, 146-47.
61. The title of Hasse, Letze Äusserungen, could be translated as “Kant’s last remarks, by one of his dinner companions” and Reusch, Kant und seine Tischgenossen as “Kant and his dinner companions.”
62. Abegg, Reisetagebuch, 255. This topic might strike some as too trivial to discuss, but these dinners were a central part of Kant’s life. Kuehn draws a plausible connection between this conversational form of life and Kant’s critical philosophy (Kant, 273-74).
63. Quoted in Hugelmann, “Ein Brief,” 610. See also Hasse, Letze Äusserungen, 6-7. Nor did Jachmann ever hear Kant mention any of his writings during these dinnertime conversations (Immanuel Kant, 137). Vorländer offers a close description of the rituals surrounding Kant’s dinner parties in his home (Immanuel Kant, 2:297-300).
64. This idea is usefully explored in Alix A. Cohen, “The Ultimate Kantian Experience: Kant on Dinner Parties,” History of Philosophy Quarterly 25, no. 4 (Oct. 2008): 315-36.
65. C. J. Kraus, quoted in Reicke, Kantiana, 60. Johann Ludwig Schwarz was staying with the Keyserlings in February or March of 1787 and mentions dining with Kant four of the five days he was there, so clearly Kant was often more than just a Tuesday guest. See Schwarz, Denkwürdigkeiten aus dem Leben eines Geschäftsmannes, Dichters und Humoristen (Leipzig: Kollmann, 1828), 180.
66. This was a peacefully conducted arrangement that occurred during the Seven Years War.
67. A note in the November 21, 1786, issue of the Allgemeinen Literaturzeitung claims that the new edition of the Critique of Pure Reason would also include a “Critique of Pure Practical Reason” (Ak 3:556).
68. And yet we know from the Vigilantius metaphysics notes from that very semester that Kant did indeed lecture on natural theology, some 36 pages’ worth, although unfortunately we have only the very end of the discussion.
69. “On the Causes of the Earthquakes, on the Occasion of the Calamity that befell the Western Countries of Europe towards the End of Last Year” (Ak 1:419-27; NS, 329-36), “History and Natural Description of the Most Noteworthy Occurrences of the Earthquake that Struck a Large Part of the Earth at the End of the Year 1755” (Ak 1:431-61; NS, 339-64), and “Continued Observations of the Terrestrial Convulsions that have been Perceived for Some Time” (Ak 1: 465-72; NS, 367-73).
70. Reusch, Kant und seine Tischgenossen, 5.
71. Hasse, Letzte Äusserungen, 28-29.
72. Abegg, Reisetagebuch, 147. Professor Pörschke, a former student and then colleague of Kant’s, told Abegg that Kant had assured him that “he had been teaching for a long time without ever doubting any of the Christian dogma, [but] gradually one piece after another fell away” (Abegg, Reisetagebuch, 184).
73. Hagen, “Kantiana,” 16.
74. Wasianski, Immanuel Kant, 217.  

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