To my great joy I have lived to revise even this little work, after a lapse of nineteen years, and that joy is enhanced by the special importance of this treatise for my philosophy. For, starting from the purely empirical, from the observations of unbiassed physical investigators--themselves following the clue of their own special sciences--I here immediately arrive at the very kernel of my Metaphysic; I establish its points of contact with the physical sciences and thus corroborate my fundamental dogma, in a sense, as the arithmetician proves a sum: for by this I not only confirm it more closely and specially, but even make it more clearly, easily, and rightly understood than anywhere else. The improvements in this new edition are confined almost entirely to the Additions; for scarcely anything that is worth mentioning in the First Edition has been left out, while I have inserted many and, in some cases, important new passages. But, even in a general sense, it may be looked upon as a good sign, that a new edition of the present treatise should have been found necessary; since it shows that there is an interest in serious philosophy and confirms the fact that the necessity for real progress in this direction is now more strongly felt than ever. This is based upon two circumstances. The first is the unparalleled zeal and activity displayed in every branch of Natural Science which, as this pursuit is mostly in the hands of people who have learned nothing else, threatens to lead to a gross, stupid Materialism, the _more immediately_ offensive side of which is less the moral bestiality of its ultimate results, than the incredible absurdity of its first principles; for by it even vital force is denied, and organic Nature is degraded to a mere chance play of chemical forces.[166] These knights of the crucible and retort should be made to understand, that the mere study of Chemistry qualifies a man to become an apothecary, but not a philosopher. Certain other like-minded investigators of Nature, too, must be taught, that a man may be an accomplished zoologist and have the sixty species of monkeys at his fingers' ends, yet on the whole be an ignoramus to be classed with the vulgar, if he has learnt nothing else, save perhaps his school-catechism. But in our time this frequently happens. Men set themselves up for enlighteners of mankind, who have studied Chemistry, or Physics, or Mineralogy and nothing else under the sun; to this they add their only knowledge of any other kind, that is to say, the little they may remember of the doctrines of the school-catechism, and when they find that these two elements will not harmonize, they straightway turn scoffers at religion and soon become shallow and absurd materialists.[167] They may perhaps have heard at college of the existence of a Plato and an Aristotle, of a Locke, and especially of a Kant; but as these folk never handled crucibles and