As I have absolutely nothing to advance against these reproaches, I only hope for some small thanks from such readers for having warned them in time, so that they may not lose an hour over a book which it would be useless to read without complying with the demands that have been made, and which should therefore be left alone, particularly as apart from this we might wager a great deal that it can say nothing to them, but rather that it will always be only _pancorum hominum_, and must therefore quietly and modestly wait for the few whose unusual mode of thought may find it enjoyable. For apart from the difficulties and the effort which it requires from the reader, what cultured man of this age, whose knowledge has almost reached the august point at which the paradoxical and the false are all one to it, could bear to meet thoughts almost on every page that directly contradict that which he has yet himself established once for all as true and undeniable? And then, how disagreeably disappointed will many a one be if he finds no mention here of what he believes it is precisely here he ought to look for, because his method of speculation agrees with that of a great living philosopher,(1) who has certainly written pathetic books, and who only has the trifling weakness that he takes all he learned and approved before his fifteenth year for inborn ideas of the human mind. Who could stand all this? Therefore my advice is simply to lay down the book. But I fear I shall not escape even thus. The reader who has got as far as the preface and been stopped by it, has bought the book for cash, and asks how he is to be indemnified. My last refuge is now to remind him that he knows how to make use of a book in several ways, without exactly reading it. It may fill a gap in his library as well as many another, where, neatly bound, it will certainly look well. Or he can lay it on the toilet-table or the tea-table of some learned lady friend. Or, finally, what certainly is best of all, and I specially advise it, he can review it. ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ And now that I have allowed myself the jest to which in this two-sided life hardly any page can be too serious to grant a place, I part with the book with deep seriousness, in the sure hope that sooner or later it will reach those to whom alone it can be addressed; and for the rest, patiently resigned that the same fate should, in full measure, befall it, that in all ages has, to some extent, befallen all knowledge, and especially the weightiest knowledge of the truth, to which only a brief triumph is allotted between the two long periods in which it is condemned as paradoxical or disparaged as trivial. The former fate is also wont to befall its author. But life is short, and truth works far and lives long: let us speak the truth. _Written at Dresden in August 1818._ PREFACE TO THE SECOND EDITION.