failed to perceive the necessity of such a procedure must be ascribed to the dogmatic mode of thought which characterized his age, and on this point the philosophers of his time, as well as of all previous times, have nothing to reproach each other with. Those who reject at once the method of Wolf, and of the Critique of Pure Reason, can have no other aim but to shake off the fetters of science, to change labour into sport, certainty into opinion, and philosophy into philodoxy. In this second edition, I have endeavoured, as far as possible, to remove the difficulties and obscurity which, without fault of mine perhaps, have given rise to many misconceptions even among acute thinkers. In the propositions themselves, and in the demonstrations by which they are supported, as well as in the form and the entire plan of the work, I have found nothing to alter; which must be attributed partly to the long examination to which I had subjected the whole before offering it to the public and partly to the nature of the case. For pure speculative reason is an organic structure in which there is nothing isolated or independent, but every Single part is essential to all the rest; and hence, the slightest imperfection, whether defect or positive error, could not fail to betray itself in use. I venture, further, to hope, that this system will maintain the same unalterable character for the future. I am led to entertain this confidence, not by vanity, but by the evidence which the equality of the result affords, when we proceed, first, from the simplest elements up to the complete whole of pure reason and, and then, backwards from the whole to each part. We find that the attempt to make the slightest alteration, in any part, leads inevitably to contradictions, not merely in this system, but in human reason itself. At the same time, there is still much room for improvement in the exposition of the doctrines contained in this work. In the present edition, I have endeavoured to remove misapprehensions of the aesthetical part, especially with regard to the conception of time; to clear away the obscurity which has been found in the deduction of the conceptions of the understanding; to supply the supposed want of sufficient evidence in the demonstration of the principles of the pure understanding; and, lastly, to obviate the misunderstanding of the paralogisms which immediately precede the rational psychology. Beyond this point--the end of the second main division of the "Transcendental Dialectic"--I have not extended my alterations,* partly from want of time, and partly because I am not aware that any portion of the remainder has given rise to misconceptions among intelligent and impartial critics, whom I do not here mention with that praise which is their due, but who will find that their suggestions have been attended to in the work itself. [*Footnote: The only addition, properly so called--and that only in the method of proof--which I have made in the present edi- tion, consists of a new refutation of psychological idealism, and a strict demonstration--the only one possible, as I believe--of the objective reality of external intuition. However harmless idealism may be considered--although in reality it is not so--in regard to the essential ends of metaphysics, it must still remain a scandal to philosophy and to the general human reason to be obliged to assume, as an article of mere belief, the existence of things external to ourselves (from which, yet, we derive the whole material of cognition for the internal sense), and not to be able to oppose a satisfactory proof to any one who may call it in question. As there is some obscurity of expression in the demonstration as it stands in the text, I propose to alter the passage in question as follows: "But this permanent cannot be an intuition in me. For all the determining grounds of my existence which can be found in me are representations and, as such, do themselves require a permanent, distinct from them, which may determine my existence in relation to their changes, that is, my existence in time, wherein they change." It may, probably, be urged in opposition to this proof that, after all, I am only conscious immediately of that which is in me, that is, of my representation of external things, and that, consequently, it must always remain uncertain whether anything corresponding to this representation does or does not exist externally to me. But I am conscious, through internal experience, of my existence in time (consequently, also, of the determinability of the former in the latter), and that is more than the simple consciousness of my representation. It is, in fact, the same as the empirical consciousness of my existence, which can only be determined in relation to something, which, while connected with my existence, is external to me. 13 This consciousness of my existence in time is, therefore, identical with the consciousness of a relation to something external to me, and it is, therefore, experience, not fiction, sense, not imagination, which inseparably connects the external with my internal sense. For the external sense is, in itself, the relation of intuition to something real, external to me; and the reality of this something, as opposed to the mere imagination of it, rests solely on its inseparable connection with internal experience as the condition of its pos- sibility. If with the intellectual consciousness of my existence, in the representation: I am, which accompanies all my judgements, and all the operations of my understanding, I could, at the same time, connect a determination of my existence by intellectual intuition, then the consciousness of a relation to something external to me would not be necessary. But the internal intuition in which alone my existence can be determined, though preceded by that purely intellectual consciousness, is itself sensible and attached to the condition of time. Hence this determination of my existence, and consequently my internal experience itself, must depend on something permanent which is not in me, which can be, therefore, only in something external to me, to which I must look upon myself as being related. Thus the reality of the external sense is necessarily connected with that of the internal, in order to the possibility of experience in general; that is, I am just as certainly conscious that there are things external to me related to my sense as I am that I myself exist as determined in time. But in order to ascertain to what given intuitions objects, external me, really correspond, in other words, what intuitions belong to the external sense and not to imagination, I must have recourse, in every particular case, to those rules according to which experience in general (even internal experience) is distinguished from imagination, and which are always based on the proposition that there really is an external experience. We may add the remark that the representation of something permanent in existence, is not the same thing as the permanent representation; for a representation may be very variable and changing--as all our representations, even that of matter, are--and yet refer to something permanent, which must, therefore, be distinct from all my representations and external to me, the existence of which is necessarily included in the determination of my own existence, and with it constitutes one experience--an experience which would not even be possible internally, if it were not also at the same time, in part, external. To the question How? we are no more able to reply, than we are, in general, to think the stationary in time, the coexistence of which with the variable, produces the conception of change.] In attempting to render the exposition of my views as intelligible as possible, I have been compelled to leave out or abridge various passages which were not essential to the completeness of the work, but which many readers might consider useful in other respects, and might be unwilling to miss. This trifling loss, which could not be avoided without swelling the book beyond due limits, may be supplied, at the pleasure of the reader, by a comparison with the first edition, and will, I hope, be more than compensated for by the greater clearness of the exposition as it now stands. I have observed, with pleasure and thankfulness, in the pages of various reviews and treatises, that the spirit of profound and thorough investigation is not extinct in Germany, though it may have been overborne and silenced for a time by the fashionable tone of a licence in thinking, which gives itself the airs of genius, and that the difficulties which beset the paths of criticism have not prevented energetic and acute thinkers from making themselves masters of the science of pure reason to which these paths conduct--a science which is not popular, but scholastic in its character, and which alone can hope for a lasting existence or possess an abiding value. To these deserving men, who so happily combine profundity of view with a talent for lucid exposition--a talent which I myself am not conscious of possessing--I leave the task of removing any obscurity which may still adhere to the statement of my doctrines. For, in this case, the danger is not that of being refuted, but of being misunderstood. For my own part, I must hencefor-ward abstain from controversy, although I shall carefully attend to all suggestions, whether from friends or adversaries, which may be of use in the future elaboration of the system of this propaedeutic. As, during these labours, I have advanced pretty far in years this month I reach my sixty-fourth year--it will be necessary for me to economize time, if I am to carry out my plan of elaborating the metaphysics of nature as well as of morals, in confirmation of the correctness of the principles established in this Critique of Pure Reason, both speculative and practical; and I must, therefore, leave the