VARIOUS THEORIES OF THE ORGANISM 29 



The living organism has often been compared to a machine made 

 by man, such as the steam engine, which converts a part of the 

 energy of the fuel into function as the organism transforms the 

 energy of nutrition into functional activity. This analogy is a 

 very imperfect one, for in the steam engine and in all other machines 

 constructed by man structure and function are separable. More- 

 over, the man-made machine does not construct itself by its func- 

 tional activity, but is completely passive as regards its construction, 

 being built up by an agent external to itself for a definite purpose, 

 and being unable to function until its structure is completed. The 

 organism, on the other hand, functions from the beginning and con- 

 structs itself by its own functional activity; and the structure 

 already present at any given time is a factor in determining the 

 function, and the function at any given time is a factor in determin- 

 ing the future structure. The organism is then a very different 

 thing from a man-made machine, and comparisons between the 

 two are likely to lead to incorrect conclusions concerning the organ- 

 ism. The machine corresponds more closely to a fully developed 

 morphological part of the organism which constitutes a definite 

 functional mechanism. But the structure and function of such a 

 part give us no conception of the organism as a whole and of its 

 action as a constructive and activating agent. 



The comparison between the living organism and the man- 

 made machine completely ignores the relation between structure 

 and function in the former. And any conception of the organism 

 which does not take into account its ability to construct its own 

 mechanism is very far from adequate. The whole living organism 

 may be compared with the machine plus the constructing and 

 activating agent, the intelligence that makes and runs it. It may 

 appear at first glance that this view leads necessarily to the assump- 

 tion that an intelligence more or less like that of man is concerned 

 in the development of every organism. This, however, is far from 

 being the case. In the broad sense, the man building and running 

 a machine is an organism constructing a part with a definite func- 

 tional mechanism which functions under the control of the whole. 



If intelligence is a function of the human or any other organism, 

 then the same laws must hold for its activity as for that of organisms 



