224 EVOLUTION AND MAX S PLACE IN NATURE 



elated by his sense of sinell, and his sight, and his 

 appetite ? Do we get beyond interpretation of signs ? 

 The porridge and the biscuit, the white and the 

 hard, all influence his susceptibilities; but there is 

 not sufficient evidence that he has ideas such as we 

 have, when we use these terms. 



Risks of onesidedness need to be guarded against 

 here. These may be escaped, by passing from com 

 parative biology, into a section of our literature dealing 

 with the characteristics of human intelligence. We 

 shall thus be placed in possession of descriptions and 

 definitions bearing on the intelligent life of man, 

 which were shaped with no other end in view than 

 that of securing an accurate understanding of our own 

 familiar mental exercise. Take for example that 

 section in the history of British philosophy represented 

 by the names of Locke, Hume, and Reid. The three 

 names are representative of three distinct phases of 

 thought, while the thinkers are historically related. 

 The combination of the three secures several ad 

 vantages. Locke says the term idea serves best 

 to stand for whatsoever is the object of the under 

 standing when a man thinks: I have used it to 

 express whatever is meant by phantasm, notion, 

 species, or whatever it is which the niind may be 

 employed about in thinking/ l Hume distinguishes 

 between impressions and ideas. By impressions he 

 means all our sensations, passions, and emotions, as 

 they make their first appearance in the soul. By 

 ideas he means * the faint images of these in thinking 

 and reasoning. 2 Reid, conducting a polemic against 



1 Locke s Essay concerning the Human Understanding, Bk. I. Ch. i. 

 S. Hume s Human Xatttre, Bk. i. Pt. i. sec. 1. 



