42 THE PHILOSOPHY OF BIOLOGY 



our thought, concepts that facilitate our descriptions. 

 When an anatomist gives an account of the structure 

 of an animal he does not say what it looks like, nor as 

 a rule does he content himself by making a photograph 

 of his dissections. For him the animal is a complex of 

 muscles, skeleton, nerves, glands, and so on, and in his 

 drawings all these things are given an individuality 

 that they do not really possess. In the living creature 

 there were no such sharply-distinguished organs as a 

 good drawing represents : all are bound together and 

 are continuous. But for practical convenience in 

 description — that is, in the long run, that we may 

 act upon these things, we isolate from each other aspects 

 that are in reality one unitary whole. 



The universe, that is, all that is given to us, presents 

 itself as immediately perceived phenomena which are 

 then conceptually transformed. It is an aggregate of 

 things — gross matter, particles, molecules, atoms, and 

 electrons. These things have separate existence and 

 shape, so that each of them lies outside all other things 

 — we apply to them the category of extension. They 

 possess properties — that is, they are hard, or heavy, or 

 hot, or cold, or they are coloured, or they smell, and 

 so on — we thus apply to them the category of in- 

 herence. They are not things that are immutable, for 

 they change in place, or are transformed in other ways, 

 that is, they are acted upon by energies. But beneath 

 the properties of the things, or the transformations 

 that they undergo, we imagine something that has 

 properties and which transforms : it is not convenient 

 that we speak solely of attributes or transformations 

 as entities in themselves, for we think of things as 



