Esteemed Sir,

He who has the pleasure of delivering this letter to you is the son of one of the finest men serving Frederick the Great. His worthy father, who knows you, thought that to this significant recommendation my own recommendation would make an additional contribution. Since this opinion of how you estimate my worth is so flattering to me, I would like in any case to be able to preserve it among good people, and you, dearest Herr Professor, you love me really too well to impute this to my vanity. In any case, every young person who strives after wisdom is recommended like a son to you and this one has authenticated witnesses testifying that he is worthy of your guidance.

I don't know what persons from Königsberg assured me several months ago that you were going to visit us this summer, traveling beyond here to Pyrmont or Spa. Can your friends hope for this? Such a journey would on the whole be good for you, even without bath and springs, and I should think that you were obligated to sacrifice to Aesculapius your convenience and the whole army of scruples which a clever hypochondria can bring up to oppose the journey. You would find many open arms in Berlin, but also many an open heart, among them one that belongs to a man who voices his admiration for you even if he cannot follow you.

Dear and revered Sir,

The reason I delayed so long in telling you of the pleasure your letter gave me is that I value your time too highly, so that I allow myself to pilfer some of it only when it will serve to relieve my heart and not merely satisfy an impulse, and this you have already done for me once, when my spirit was most turbulent and I appealed to you for help, you understood me so perfectly that because of your kindness and your precise comprehension of the human heart I am encouraged to describe to you without embarrassment the further progress of my soul. The lie on account of which I appealed to you was no cloaking of a vice but only a sin of omission, holding something back out of consideration for the friendship (still veiled by love) that existed then. The conflict I felt, foreseeing the terribly painful consequences and knowing the honesty one owes to a friend, was what made me disclose the lie to my friend after all, but so late. Finally I had the strength, and with the disclosure I got rid of the stone in my heart at the price of the tearing away of his love. I enjoyed as little peace before, when I begrudged myself the pleasure I possessed, as afterward, when my heart was torn apart by the suffering and anguish that plagued me and that I wouldn't wish on anyone, even someone who would want to prove his wickedness in a court of law.

Dear Sir,

Worthiest friend,

I received your kind gift, the plaster cast of Herr Mendelssohn's medallion, via Herr von Nolte, a pleasant young gentleman, and I thank you for it.

Dr. Heintz assures me, through letters from Secretary Biester, that your lectures have been received with unusual and universal applause. Now Herr Kraus tells me exactly the same thing and informs me of the thoroughgoing respect you have earned from the Berlin public. I need not assure you of the exceptional pleasure that this evokes in me; it is obvious. What is unexpected in this is not your astuteness and insight, which I already have cause to believe in completely, but the popularity you have achieved that, in a project of this sort, would have made me fearful. For some time I have been reflecting in idle moments on the principles needed to achieve popularity in the sciences generally (obviously I mean sciences that are capable of popularity, for mathematics is not), especially in philosophy, and I think that from this perspective I can not only describe a different selection but also a wholly different organization than the methodical, scholastic one that always remains fundamental requires. However, your success shows that you have the knack for this even in your first attempts.

How I wish I had a better manuscript to give you than the one Herr Kraus will deliver to you.

Dear Sir,

I am in every way obliged to you for your most treasured letter of December 31 and should like especially to render my sincerest thanks for your efforts in connection with Herr Kanter. If it suits him I should be very pleased to see him here at Easter and to make the necessary appointments with him. I shall also have various matters to discuss with him in connection with the calendar revision that I have undertaken for the Academy. Might I beg you, sir, to inform Herr Kanter of all this when you have time. I have nothing else to say in answer to his letter. But do think up ways in which, perhaps because of my location [in Berlin], I can be of service to you, so that I shall not remain your debtor.

There is no denying it: whenever a science needs methodical reconstruction and cleansing, it is always metaphysics. The universal, which is supposed to reign in that science, leads us to suppose ourselves omniscient, and thus we venture beyond the limits of possible human knowledge. I think this shows that if we want to avoid omissions, premature inferences, and circular reasoning, we had better work piecemeal, demanding to know at every step only what is capable of being known. I think it has been an unrecognized but perennial error in philosophy to force the facts and, instead of leaving anything unexplained, to load up with conjectures, thus actually delaying the discovery of the truth.

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.

2. […]

Esteemed Sir,

This is the second time in my life that I write to you; you will recall that some years ago I sent you a little tract, “Glimpses into the Secrets of Natural Philosophy,” which I had had printed anonymously. But now I speak to you in an entirely different tone; now what I must do is to thank you with my whole heart.

The total story of my life, which has been published by Decker in Berlin under the title “Stilling,” demonstrates how much reason I have to believe in a God, a Redeemer, a teacher of mankind, and in a special providence. My biography shows how dreadful philosophical confusion and nonsense, Pro and Contra rationalizing, made it necessary to hold fast to the New Testament if I were to avoid sinking into a bottomless, groundless abyss. Yet my reason struggled perpetually for apodictic certainty, which neither the Bible nor Wolf nor mystics nor Hume nor Loke [sic] nor Swedenborg nor Helvetius could give me. Unconditional, fearful, anxious faith was thus my lot, while at the same time Determinism with all its conquering power pressed on my heart, my understanding, my reason, imprisoning me completely and gradually subduing me. No foe was ever more horrible to me than determinism; it is the greatest despot of humanity, strangling every incipient attempt at goodness and every pious trust in God, and yet determinism is so reliable, so certainly true, so evident to every thinking mind, that the world is inescapably lost, religion and morality are destroyed, just as soon as we isolate our sense world and believe the world to be in itself exactly as we imagine it and think.

Dear Friend,

Aren't you surprised that I dare to write to you, a great philosopher? I thought I would find you in my garden yesterday, but since my girlfriend and I crept through all the alleys and failed to find our friend under this circle of heaven I spent my time finishing a rapier ribbon, it is dedicated to you. I make claim on your company tomorrow afternoon. I hear you say, “Yes, yes, I'll come.” Well good, we shall await you and then my watch will get wound. Forgive me this reminder. My girlfriend and I send you a kiss by means of sympathy – surely the air must be the same in Kneiphoff, so our kiss won't lose its sympathy-power. May you live happily and well

Worthiest friend,

I have made you wait a long time for a response to your letter of December 9 of last year, but it is not my fault. For pressing labors hang about my neck and my age imposes on me a necessity I would not otherwise feel, to devote my thoughts to the project before me until I am finished with it. I must not let anything alien interrupt my thinking, for once I let go of the thread, I cannot find it again.

You have presented me with your thorough investigation of what is just the hardest thing in the whole Critique, namely, the analysis of an experience in general and the principles that make experience in general possible. – I have already made plans for a system of metaphysics to handle this difficulty and to begin with the categories, in their proper order (having first merely expounded, without investigating their possibility, the pure intuitions of space and time in which alone objects can be given to the categories); and I would demonstrate, at the conclusion of the exposition of each category (for example, Quantity and all predicables included under it, along with examples of their use), that no experience of objects of the senses is possible except insofar as I presuppose a priori that every such object must be thought of as a magnitude, and similarly with all the other categories.

Reverend, esteemed Sir,

I seize this opportunity to express to you the respect and friendship which my customary negligence in letter writing might otherwise have made you doubt. It is with a certain vanity that I observed the discriminating approbation which your recent essays have received from the public, even though they are entirely your own achievement and owe nothing to my instruction. If criticism did not have the unfortunate tendency to make a man of genius timorous, and if nicety of judgment did not make self-approval so difficult, I would venture the hope, based on the fragments I have from you, that I might live to see you become in time a master of that sort of philosophical poetry in which Pope excels. Observing the precocious development of your talents I anticipate with pleasure the time when your fertile mind, no longer so buffeted by the warm winds of youthful feeling, will achieve that gentle but sensitive tranquility which is the contemplative life of a philosopher, just the opposite of the life that mystics dream about. I look forward to that epoch of your genius with confidence – confidence being a frame of mind that is most beneficial both to its possessor and to the world; it is a frame of mind that Montange [sic] possessed hardly at all and Hume, as far as I know, exemplifies to the highest degree.

Noble Sir,

Esteemed Herr Professor,

With sincerest pleasure I take this opportunity, while carrying out an assignment I have been given, to let you know of my great sympathy for your excellent school, the Philanthropin.

Herr Robert Motherby, a local English merchant and my dear friend, would like to entrust his only son, George Motherby, to the care of your school. Herr Motherby's principles agree completely with those upon which your institution is founded, even in those respects in which it is farthest removed from ordinary assumptions about education. The fact that something is unusual will never deter him from freely agreeing to your proposals and arrangements in all that is noble and good. His son will be six years old on the seventh of August this year. But though he has not reached the age you require, I believe that his natural abilities and motivations are already such as to satisfy the intent of your requirement. That is why his father wants no delay in bringing the boy under good guidance, so that his need for activity may not lead him to any bad habits that would make his subsequent training more difficult. His education thus far has been purely negative, which I regard as the best that can be done for a child in those years. He has been allowed to develop his nature and his healthy reason in a manner appropriate to his years, without compulsion, and has been restrained only from those things that might set his mind in a wrong direction.

Noble Sir,

Esteemed friend,

It pleases me to receive news of the good progress of your endeavors, but even more to see the signs of kind remembrance and of friendship in the communications imparted to me. Training in the practice of medicine, under the guidance of a capable teacher, is exactly what I wish. The cemetery must in the future not be filled before the young doctor has learned how to attack the disease properly. Do make many careful observations. Here as elsewhere, theories are often directed more to the relief of the idea than to the mastery of the phenomenon. Macbride's Systematic Medical Science (I believe you are already acquainted with it) appealed to me very much in this regard. In general, I now feel much better than before. The reason is that I now understand better what makes me ill. Because of my sensitive nerves, all medicines are without exception poison for me. The only thing I very occasionally use is a half teaspoonful of fever bark with water, when I am plagued by acid before noon. I find this much better than any absorbentia. But I have given up the daily use of this remedy, with the intention of strengthening myself. It gave me an irregular pulse, especially toward evening, which rather frightened me, until I guessed the cause and, adjusting it, relieved the indisposition.

Esteemed friend and teacher,

I thank you sincerely for your kind letter which did my heart good. My veneration for you is so great that you could not offend me in any way; certainly not by anything as easily explained as your delay in responding to me. But it would have depressed me, having achieved what I took to be your good opinion of me, to see it lost. I live in the midst of people who delight in gossip and story-mongering. I don't mean by that our Jena, where for the most part people have more serious things to do, but the whole area around here. For years I have heard anecdotes of all sorts. I can well imagine how one might finally get sick of philosophy. It is not the natural air for human beings to breathe – it is not the end but the means. A person who has achieved the end – full development of his mind and complete harmony with himself – will put aside the means. That is your situation, esteemed old man.

Since you yourself say that “you gladly leave to others the subtlety of theoretical speculation, especially when it concerns the outer apexes,” I feel more at ease about the adverse judgments of my system which practically everybody in the multitudinous ranks of German philosophers claims to have heard from you.

Dear Sir:

I believe that the similarity of our ways of thinking will excuse this letter, its frankness, and the omission of customary circumlocutions. I need no such artificial mannerisms, since Professor and Pastor Reccard's trip to Königsberg gives me such a fine opportunity to express to you the pleasure I feel at our agreement on so many new thoughts and investigations. You may already have learned from the Reverend Dr. Reccard, dear sir, that he lives for the sake of astronomy, and finds his pleasure in the depths of the firmament. I need not recommend him further.

A year ago Professor Sulzer showed me your Only Possible Proof for the Existence of God. I found in it my own thoughts and even the phrases I would choose to express them, and I decided at once that if you were to see my Organon you too would find yourself mirrored in most of its pages. Since then, I had worked out my Architektonic and the book was already prepared for publication a year ago. And now I learn, dear sir, that you are going to publish a Proper Method for Metaphysics this coming Easter. What could be more natural than my desire to see whether what I have done is in accord with the method you propose? I have no doubts as to the correctness of the method.