THE HIS TORY OF ZOOLOGY 503 



It is interesting to note that this same difficulty was felt at 

 about the same time by the great German philosopher, Kant 

 (1724-1804). His views, so clearly stated in 1790, represent the 

 most advanced thought of the century on the subject ol evolu- 

 tion. He says : " The agreement of so many kinds of animals 

 in a certain common plan of structure, which scorns to be visible 

 not only in their skeletons, but also in the arrangement of the 

 other parts, so that a wonderfully simple typical form, by the 

 shortening and lengthening of some parts and by the suppres- 

 sion and development of others, might be able to produce an 

 immense variety of species, gives us a ray of hope, though 

 feeble, that here perhaps some results may be obtained, by the 

 application of the principle of the mechanism of Nature, with- 

 out which, in fact, no science can exist. This analogy of forms 

 (in so far as they seem to have been produced in accordance 

 with a common prototype, notwithstanding their great variety) 

 strengthens the supposition that they have an actual blood rela- 

 tionship due to derivation from a common parent; a supposition 

 which is arrived at by observations of the gradual approxi- 

 mation of one class of animals to another, beginning with the 

 one in which the principle of purposiveness seems to be most 

 conspicuous, namely man, and extending down to the polyps, 

 and from these even down to mosses and lichens, and arriving 

 finally at raw matter, the lowest stage of nature observable by 

 us. From this raw matter and its forces, the whole apparatus 

 of Nature seems to have been derived according to mechanical 

 laws (such as those which resulted in the production of crystals) ; 

 yet this apparatus, as seen in organic beings, is so incompre- 

 hensible to us, that we feel ourselves compelled to conceive for 

 it a different principle." And elsewhere he writes : " It is quite 

 certain that we cannot become sufficiently acquainted with 

 organized creatures and their hidden potentialities by aid of 

 purely mechanical natural principles, much less can we explain 

 them ; and this is so certain, that we may boldly assert that it is 

 absurd for man even to conceive such an idea, or to hope that a 

 Newton may one day arise to make even the production of a 

 blade of grass comprehensible, according to natural laws or- 

 dained by no intention; such an insight we must absolutely 

 denv to man." 



