10 The Universe and Life 



Thus the biologist has two sets of data, discovered 

 in somewhat different ways, one set being discoverable 

 only through the fact that the biologist is himself a 

 biological specimen. We shall require some brief 

 method of distinguishing the two ways of discovering 

 facts about biological material. For this purpose I 

 shall use the common words outer and inner. We shall 

 call the method of observing other things and other in- 

 dividuals, as the physicist does, the outer view ; while 

 discovering things through the fact that the biologist 

 is himself a biological specimen, we shall call the inner 

 view. And we shall call the things discovered by the 

 outer view, the physical phenomena or aspects, while 

 for the things that are discoverable only by the inner 

 view — by being one's self a biological specimen — we 

 shall use the word mental. There are objections to all 

 these terms, but they may serve. Under the mental, 

 therefore, we shall include sensations, feelings, de- 

 sires, purposes, thoughts, and kindred phenomena. 

 Whether the two sets of data — the physical and the 

 mental — differ in some other fundamental way, so 

 that they can be said to be different in kind, is a matter 

 with which we need not concern ourselves. The verifi- 

 able fact is that the two sets of data exist, and that 

 they are discovered in somewhat different ways. 



These two sets of data then are the materials with 

 which the biologist has to deal. But with relation to 

 them, an extraordinary situation has arisen in biologi- 

 cal science; a situation that must excite surprise in 

 anyone who is not a technical biologist ; but a situation 

 which one must have in mind if he is to understand the 



