ii4 ASSAYS SCIENTIFIC AND PHILOSOPHICAL. 



by which such conclusions are established. Still, 

 for understanding the theory of ethics developed in 

 Books III. and IV., it is necessary to do this. 



At the end of the Introduction two questions are 

 suggested for consideration, of which the second 

 depends upon a negative answer being given to 

 the first : 



" Can the knowledge of nature be itself a part or product 

 of nature in that sense of nature in which it is said to be an 

 object of knowledge ? " 



This is the question of Book I. If the answer 

 be in the negative the further question is suggested 

 namely, whether that principle in knowledge 

 which is not natural has not another expression 

 in the consciousness of a moral ideal. Thus the 

 Second Book leads us on from the critique of the 

 speculative to that of the practical reason. 



It would be difficult to find in the English lan- 

 guage so clear a statement of great metaphysical 

 principles as we have in Book I. on the metaphysic 

 of knowledge. Metaphysicians, from Heracleitus 

 to Hegel, have a tendency to adopt a defiant atti- 

 tude towards ordinary people. There is nothing 

 of this in Professor Green. Even when he is 

 dealing with the most abstruse subjects he wishes 

 to be understood ; and the wish to be understood 

 carries him on far towards the attainment of his 

 object. Whether it is that English people are too 

 matter-of-fact to be metaphysical, or that they 



