3H 



NATURE 



\Angust 15, 1889 



supposed substratum of qualities. But, according to 

 Kant, Berkeley confused matter as a substratum of 

 qualities with matter as a thing per se. No doubt we 

 can never prove the existence of matter as a thing per se. 

 On the other hand, the notion of a substratum is neces- 

 sary in our knowledge in order to account for that 

 permanence without which there would be for us no real 

 world at all. This permanent substratum is \\.'s,&\i pheno- 

 vteital, because we can form no notion of permanence 

 except in space, and space is a form of sensible intuition. 

 Hence Kant would be the last to sanction any speculations 

 on the permanence of unknown things per se : he is no 

 materialist in the vulgar sense of the word ; but he is, to 

 the extent above explained, a problematical realist, in so 

 far as he accepts the necessary principle of a permanent 

 phenomenal substratum. If we further ask. Whence do 

 we obtain this notion of permanence ? Kant answers that 

 we derive it " from the fact that all our experience is 

 comprised in one time, which time cannot be perceived 

 in itself, but only when occupied by some perception. 

 Hence we infer the permanence of the matter of ex- 

 perience, of phenomenal substance, the changing states 

 of which correspond to the various portions of changing 

 time comprised in the one great complex of time. Thus 

 we represent to ourselves the permanent, even though we 

 have no permanent representation ; and as an empirical 

 criterion of this permanence in time, we use impene- 

 trability, or modes of resistance in space " (p. 213). 



Kant was, however, not content with merely indicating 

 the equal authority of external experience as compared 

 with internal experience. He advances to a still bolder 

 position. While both external and internal experience, 

 although they can give us no information concerning, 

 objects /^r se, are equally immediate and equally certain 

 Kant thinks that it can also be proved that in some re- 

 spects external experience is the more important of the 

 two. For internal experience is, after all, only possible if 

 we presuppose external experience. Internal experience is 

 subject to the form of time ; it is made up of changing 

 modes of consciousness. But change can only be under- 

 stood if we already have the notion of permanence (" only 

 the permanent can change," says Kant), and the notion 

 of permanence is to be found in that permanent sub- 

 stratum which underlies all our external experience. 

 Hence it is so little true that internal experience is more 

 certain than external that the reverse is almost the case. 

 Without external experience there would be for us no 

 possibility of internal. Where Kant's critics have gener- 

 ally gone wrong is in assuming that where Kant speaks 

 of a permanent substratum he means a thing per se. But 

 this is not the case. What he means is a phenomenal 

 substratum, the non-recognition of which is the fatal error 

 of Berkeley. 



We have spent so much time and space over this 

 point that we have left ourselves but little opportunity 

 to speak of others. But we do not think we are wrong in 

 assuming it as the point of capital importance in Dr. 

 Mahaffy's new edition, especially as it is at once the most 

 original and the most effective part of his polemic against 

 Kuno Fischer and other German critics. But there are 

 many other features which deserve attention, although we 

 can do no more than refer to them. We would especially 

 direct the reader to the following. Let him observe Dr. 



Mahaffy's clear explanations of Kant's passage from the 

 ordinary table of logical judgment to that of the cate- 

 gories (pp. 80 ef seq.), his treatment of the categories 

 themselves (pp. 88 et seq.), as well as his vindication o^ 

 Kant against Mansel, Fichte, and other critics of the 

 categories (pp. 100 ct seq.). Chapter vii., on the deduc- 

 tion of the categories, is an important one, especially as 

 it compares the " Prolegomena " with the " Kritik." If Dr. 

 Mahaffy has not been able to bring into clearer light the 

 difficult and unsatisfactory treatment which Kant has 

 given to his principle of causality (pp. 180 ei seq.), he at 

 all events has effectively criticized Schopenhauer's carpings 

 at the Kantian categories and schemata (pp. i^i et seq.). 

 Mr. Bernard' s contributions to the commentary beginwith 

 chapter xvii., and deal with Kant's " Dialectic of the Pure 

 Reason," but we believe that for most students the chief 

 interest of this new edition will be found to be con- 

 centrated in the commentary on the "Analytic." It should 

 be added that the second volume is a translation of Kant's 

 " Prolegomena," and contains also, in the appendi.x, the 

 suppressed passages of the first edition of the " Kritik.'' 

 The whole edition forms a striking and valuable version 

 of the logical views of Kant, and we can imagine no more 

 helpful text-book both for older and younger students 

 of Kant's immortal " Kritik." W. L. Courtney. 



OUR BOOK SHELF. 



Monograph of the Mariiie and Fresh-water Ostracoda of 

 the North Atlantic and of North- Western Europe. By 

 Dr. G. S. Brady and Rev. A. M. Norman. (London : 

 Williams and Norgate, 1889.) 



About twenty-one years ago Dr. G. S. Brady published, 

 in the Transactions of the Linnean Society of London, a 

 monograph of recent British Ostracoda. The present 

 monograph is to some extent a supplement to the former 

 one, but as it embraces the description of the forms be- 

 longing to a greatly extended area, it may be regarded in 

 the light of a new work, in the publication of which the 

 authors have been ably assisted by the contributions of 

 most of those zoologists interested in this group of Crus- 

 tacea. The present memoir deals only with the section of 

 the Podocopa. The geographical-area embraces the Arctic 

 Seas, the North Atlantic Ocean, and North-Western 

 Europe. The North Atlantic area is fixed at 35° N., 

 thus excluding the tropical species of the West indies 

 and the Gulf of Mexico ; the Mediterranean is not 

 included, as the doing so would have too greatly extended 

 the limits of the work; and the North-Western European 

 area embraces Austria, Germany, France, Belgium, 

 Holland, Denmark, Scandinavia, and the British Islands. 

 The distribution of the living species, as far as known, 

 is recorded. One hundred and eighty-eight species in- 

 habiting salt water are recorded, and sixty-one fresh-water 

 forms, and yet it is certain that the record is still very 

 incomplete. While the marine species of Norway and 

 Sweden have been in part studied, little has been done 

 with respect to the marine species of Denmark and 

 Germany. The knowledge of the Dutch marine forms 

 has been derived from some dredgings in the Rivers Maas 

 and Scheldt. Those of the Belgian and French coasts 

 are also but little known, and the same may be said of 

 the truly Arctic species, while nothing is known of the 

 forms inhabiting the coasts of the United States or 

 Canada. 



The fresh-water Ostracods of Norway and Sweden, 

 have been more or less investigated by G. O. Sars anc' 

 Lilljeborg ; in Denmark by no one since the time of O. 

 F. Miiller (1785) ; in Holland not at all ; in Belgium onlj^ 



