INTRODUCTION. 



geology, not to imaginary " catastroplies," but to the forces 

 which we see at work in the world around us. And in 

 like manner, as I believe, the question of the origin of The ques- 

 species, which is the great question of the science of life, ^^^^^ ^f ^ 

 Avill be solved, and has already begun to be solved, by species. 

 means of the ordinary laws of variation and development. 

 I purpose to devote several chapters to this subject, and 

 hope to throw on it a few rays of original light. 



But the modern sense of the connexion and inter- 

 dependence of all things goes very much deeper than the 

 mere identification of physical laws. A most valuable 

 habit has become general among men of mental cultivation. Habit of 

 of regarding every subject, not as if it were alone and u'lf ^Jubj^elt 

 isolated, but in its connexion with other subjects. ^s isolated. 



Perhaps the best instance of this is one which I have 



already mentioned, namely, the altered way in wliich the 



questions of mental science are now regarded. Instead of 



beginning with the opposition of mind to matter, modern 



psvcholoav begins with the connexion of the mental with Counexion 

 r J e>j o .of mental 



the bodily nature. This modern sense of the connexion science 



of all things is altogether opposed to the tendency of the ^^1^*^^^ 

 scholastic period, which carried the love of system so far life, 

 as to endeavour to map out the whole realm of knowledge Thisiscon- 

 into provinces separated from each other by hard and ^jth the 

 definite lines. I think we may safely afQrm that if at l^^f^^^^' 

 any time the love of system were to become stronger than to isolate 

 the love of truth, the effect would be the same. And ifg^Se. 

 the attempt thus to define the province of every science 

 by means of a rigid boundary were to be successful, — 

 which of course is an impossible supposition, — it would 

 condemn science to an immobility like that of the scho- 

 lastic period. 



But a still more important effect of the modern sense of 

 the mutual connexion of all things in the bonds of law is 

 shown in the wider, and, as I believe, truer meaning with Wider 

 which we are beginning to use the word science. For g^^^^g 

 generations past, science has been usually understood to the word 



■ -. -, 1 • ^ • ^ i.i-1 science 



mean mathematical and physical science only : yet they than 

 have no exclusive right to the name. All knowledge is formerly. 



