As regards this second edition, first of all I am glad to say that after five and twenty years I find nothing to retract; so that my fundamental convictions have only been confirmed, as far as concerns myself at least. The alterations in the first volume therefore, which contains the whole text of the first edition, nowhere touch what is essential. Sometimes they concern things of merely secondary importance, and more often consist of very short explanatory additions inserted here and there. Only the criticism of the Kantian philosophy has received important corrections and large additions, for these could not be put into a supplementary book, such as those which are given in the second volume, and which correspond to each of the four books that contain the exposition of my own doctrine. In the case of the latter, I have chosen this form of enlarging and improving them, because the five and twenty years that have passed since they were composed have produced so marked a change in my method of exposition and in my style, that it would not have done to combine the content of the second volume with that of the first, as both must have suffered by the fusion. I therefore give both works separately, and in the earlier exposition, even in many places where I would now express myself quite differently, I have changed nothing, because I desired to guard against spoiling the work of my earlier years through the carping criticism of age. What in this regard might need correction will correct itself in the mind of the reader with the help of the second volume. Both volumes have, in the full sense of the word, a supplementary relation to each other, so far as this rests on the fact that one age of human life is, intellectually, the supplement of another. It will therefore be found, not only that each volume contains what the other lacks, but that the merits of the one consist peculiarly in that which is wanting in the other. Thus, if the first half of my work surpasses the second in what can only be supplied by the fire of youth and the energy of first conceptions, the second will surpass the first by the ripeness and complete elaboration of the thought which can only belong to the fruit of the labour of a long life. For when I had the strength originally to grasp the fundamental thought of my system, to follow it at once into its four branches, to return from them to the unity of their origin, and then to explain the whole distinctly, I could not yet be in a position to work out all the branches of the system with the fulness, thoroughness, and elaborateness which is only reached by the meditation of many years – meditation which is required to test and illustrate the system by innumerable facts, to support it by the most different kinds of proof, to throw light on it from all sides, and then to place the different points of view boldly in contrast, to separate thoroughly the multifarious materials, and present them in a well-arranged whole. Therefore, although it would, no doubt, have been more agreeable to the reader to have my whole work in one piece, instead of consisting, as it now does, of two halves, which must be combined in using them, he must reflect that this would have demanded that I should accomplish at one period of life what it is only possible to accomplish in two, for I would have had to possess the qualities at one period of life that nature has divided between two quite different ones. Hence the necessity of presenting my work in two halves supplementary to each other may be compared to the necessity in consequence of which a chromatic object-glass, which cannot be made out of one piece, is produced by joining together a convex lens of flint glass and a concave lens of crown glass, the combined effect of which is what was sought. Yet, on the other hand, the reader will find some compensation for the inconvenience of using two volumes at once, in the variety and the relief which is afforded by the handling of the same subject, by the same mind, in the same spirit, but in very different years. However, it is very advisable that those who are not yet acquainted with my philosophy should first of all read the first volume without using the supplementary books, and should make use of these only on a second perusal; otherwise it would be too difficult for them to grasp the system in its connection. For it is only thus explained in the first volume, while the second is devoted to a more detailed investigation and a complete development of the individual doctrines. Even those who should not make up their minds to a second reading of the first volume had better not read the second volume till after the first, and then for itself, in the ordinary sequence of its chapters, which, at any rate, stand in some kind of connection, though a somewhat looser one, the gaps of which they will fully supply by the recollection of the first volume, if they have thoroughly comprehended it. Besides, they will find everywhere the reference to the corresponding passages of the first volume, the paragraphs of which I have numbered in the second edition for this purpose, though in the first edition they were only divided by lines.

I have already explained in the preface to the first edition, that my philosophy is founded on that of Kant, and therefore presupposes a thorough knowledge of it. I repeat this here. For Kant's teaching produces in the mind of every one who has comprehended it a fundamental change which is so great that it may be regarded as an intellectual new-birth. It alone is able really to remove the inborn realism which proceeds from the original character of the intellect, which neither Berkeley nor Malebranche succeed in doing, for they remain too much in the universal, while Kant goes into the particular, and indeed in a way that is quite unexampled both before and after him, and which has quite a peculiar, and, we might say, immediate effect upon the mind in consequence of which it undergoes a complete undeception, and forthwith looks at all things in another light. Only in this way can any one become susceptible to the more positive expositions which I have to give. On the other hand, he who has not mastered the Kantian philosophy, whatever else he may have studied, is, as it were, in a state of innocence; that is to say, he remains in the grasp of that natural and childish realism in which we are all born, and which fits us for everything possible, with the single exception of philosophy. Such a man then stands to the man who knows the Kantian philosophy as a minor to a man of full age. That this truth should nowadays sound paradoxical, which would not have been the case in the first thirty years after the appearance of the Critique of Reason, is due to the fact that a generation has grown up that does not know Kant properly, because it has never heard more of him than a hasty, impatient lecture, or an account at second-hand; and this again is due to the fact that in consequence of bad guidance, this generation has wasted its time with the philosophemes of vulgar, uncalled men, or even of bombastic sophists, which are unwarrantably commended to it. Hence the confusion of fundamental conceptions, and in general the unspeakable crudeness and awkwardness that appears from under the covering of affectation and pretentiousness in the philosophical attempts of the generation thus brought up. But whoever thinks he can learn Kant's philosophy from the exposition of others makes a terrible mistake. Nay, rather I must earnestly warn against such accounts, especially the more recent ones; and indeed in the years just past I have met with expositions of the Kantian philosophy in the writings of the Hegelians which actually reach the incredible. How should the minds that in the freshness of youth have been strained and ruined by the nonsense of Hegelism, be still capable of following Kant's profound investigations? They are early accustomed to take the hollowest jingle of words for philosophical thoughts, the most miserable sophisms for acuteness, and silly conceits for dialectic, and their minds are disorganised through the admission of mad combinations of words to which the mind torments and exhausts itself in vain to attach some thought. No Critique of Reason can avail them, no philosophy, they need a medicina mentis, first as a sort of purgative, un petit cours de senscommunologie, and then one must further see whether, in their case, there can even be any talk of philosophy. The Kantian doctrine then will be sought for in vain anywhere else but in Kant's own works; but these are throughout instructive, even where he errs, even where he fails. In consequence of his originality, it holds good of him in the highest degree, as indeed of all true philosophers, that one can only come to know them from their own works, not from the accounts of others. For the thoughts of any extraordinary intellect cannot stand being filtered through the vulgar mind. Born behind the broad, high, finely-arched brow, from under which shine beaming eyes, they lose all power and life, and appear no longer like themselves, when removed to the narrow lodging and low roofing of the confined, contracted, thick-walled skull from which dull glances steal directed to personal ends. Indeed we may say that minds of this kind act like an uneven glass, in which everything is twisted and distorted, loses the regularity of its beauty, and becomes a caricature. Only from their authors themselves can we receive philosophical thoughts; therefore whoever feels himself drawn to philosophy must himself seek out its immortal teachers in the still sanctuary of their works. The principal chapters of any one of these true philosophers will afford a thousand times more insight into their doctrines than the heavy and distorted accounts of them that everyday men produce, who are still for the most part deeply entangled in the fashionable philosophy of the time, or in the sentiments of their own minds. But it is astonishing how decidedly the public seizes by preference on these expositions at second-hand. It seems really as if elective affinities were at work here, by virtue of which the common nature is drawn to its like, and therefore will rather hear what a great man has said from one of its own kind. Perhaps this rests on the same principle as that of mutual instruction, according to which children learn best from children.

One word more for the professors of philosophy. I have always been compelled to admire not merely the sagacity, the true and fine tact with which, immediately on its appearance, they recognised my philosophy as something altogether different from and indeed dangerous to their own attempts, or, in popular language, something that would not suit their turn; but also the sure and astute policy by virtue of which they at once discovered the proper procedure with regard to it, the complete harmony with which they applied it, and the persistency with which they have remained faithful to it. This procedure, which further commended itself by the great ease of carrying it out, consists, as is well known, in altogether ignoring and thus in secreting – according to Goethe's malicious phrase, which just means the appropriating of what is of weight and significance. The efficiency of this quiet means is increased by the Corybantic shouts with which those who are at one reciprocally greet the birth of their own spiritual children – shouts which compel the public to look and note the air of importance with which they congratulate themselves on the event. Who can mistake the object of such proceedings? Is there then nothing to oppose to the maxim, primum vivere, deinde philosophari? These gentlemen desire to live, and indeed to live by philosophy. To philosophy they are assigned with their wives and children, and in spite of Petrarch's povera e nuda vai filosofia, they have staked everything upon it. Now my philosophy is by no means so constituted that any one can live by it. It lacks the first indispensable requisite of a well-paid professional philosophy, a speculative theology, which – in spite of the troublesome Kant with his Critique of Reason – should and must, it is supposed, be the chief theme of all philosophy, even if it thus takes on itself the task of talking straight on of that of which it can know absolutely nothing. Indeed my philosophy does not permit to the professors the fiction they have so cunningly devised, and which has become so indispensable to them, of a reason that knows, perceives, or apprehends immediately and absolutely. This is a doctrine which it is only necessary to impose upon the reader at starting, in order to pass in the most comfortable manner in the world, as it were in a chariot and four, into that region beyond the possibility of all experience, which Kant has wholly and for ever shut out from our knowledge, and in which are found immediately revealed and most beautifully arranged the fundamental dogmas of modern, Judaising, optimistic Christianity. Now what in the world has my subtle philosophy, deficient as it is in these essential requisites, with no intentional aim, and unable to afford a means of subsistence, whose pole star is truth alone the naked, unrewarded, unbefriended, often persecuted truth, and which steers straight for it without looking to the right hand or the left, – what, I say, has this to do with that alma mater, the good, well-to-do university philosophy which, burdened with a hundred aims and a thousand motives, comes on its course cautiously tacking, while it keeps before its eyes at all times the fear of the Lord, the will of the ministry, the laws of the established church, the wishes of the publisher, the attendance of the students, the goodwill of colleagues, the course of current politics, the momentary tendency of the public, and Heaven knows what besides? Or what has my quiet, earnest search for truth in common with the noisy scholastic disputations of the chair and the benches, the inmost motives of which are always personal aims. The two kinds of philosophy are, indeed, radically different. Thus it is that with me there is no compromise and no fellowship, that no one reaps any benefit from my works but the man who seeks the truth alone, and therefore none of the philosophical parties of the day; for they all follow their own aims, while I have only insight into truth to offer, which suits none of these aims, because it is not modelled after any of them. If my philosophy is to become susceptible of professorial exposition, the times must entirely change. What a pretty thing it would be if a philosophy by which nobody could live were to gain for itself light and air, not to speak of the general ear! This must be guarded against, and all must oppose it as one man. But it is not just such an easy game to controvert and refute; and, moreover, these are mistaken means to employ, because they just direct the attention of the public to the matter, and its taste for the lucubrations of the professors of philosophy might be destroyed by the perusal of my writings. For whoever has tasted of earnest will not relish jest, especially when it is tiresome. Therefore the silent system, so unanimously adopted, is the only right one, and I can only advise them to stick to it and go on with it as long as it will answer, that is, until to ignore is taken to imply ignorance; then there will just be time to turn back. Meanwhile it remains open to every one to pluck out a small feather here and there for his own use, for the superfluity of thoughts at home should not be very oppressive. Thus the ignoring and silent system may hold out a good while, at least the span of time I may have yet to live, whereby much is already won. And if, in the meantime, here and there an indiscreet voice has let itself be heard, it is soon drowned by the loud talking of the professors, who, with important airs, know how to entertain the public with very different things. I advise, however, that the unanimity of procedure should be somewhat more strictly observed, and especially that the young men should be looked after, for they are sometimes so fearfully indiscreet. For even so I cannot guarantee that the commended procedure will last for ever, and cannot answer for the final issue. It is a nice question as to the steering of the public, which, on the whole, is good and tractable. Although we nearly at all times see the Gorgiases and the Hippiases uppermost, although the absurd, as a rule, predominates, and it seems impossible that the voice of the individual can ever penetrate through the chorus of the befooling and the befooled, there yet remains to the genuine works of every age a quite peculiar, silent, slow, and powerful influence; and, as if by a miracle, we see them rise at last out of the turmoil like a balloon that floats up out of the thick atmosphere of this globe into purer regions, where, having once arrived, it remains at rest, and no one can draw it down again.

Written at Frankfort-on-the-Maine in February 1844.