iv MECHANISM AND TELEOLOGY 297 



process to some end of value which it subserves. This 

 value may, though it need not necessarily, appertain 

 directly or indirectly to the working of some complex 

 system as a whole, and if so, it is the point of departure from 

 which the entire arrangement is to be understood, every 

 element in the system being determined by the part it plays 

 in interaction with others in contributing to the general 

 purpose. 



So far then as a system has value, every part in it is 

 determined by relation to other parts. This determination 

 has a very precise sense. Quite literally, this particular 

 eccentric is to be seen at work in this machine, was cast 

 and made true and pivoted on to its shaft because there 

 is a slide valve to be moved to and fro and a cylinder with 

 a piston moving back and forth. A modification in one of 

 these parts may produce corresponding modifications. A 

 different type of valve may require a different gearing, and 

 a turbine postulates a wholly different arrangement. In a 

 word, ideologically considered, the parts of an arrangement 

 are not indifferent to each other. They are brought into 

 existence, they are put together, they perform each its 

 proper function as parts of a totality schemed on certain 

 lines to produce a given result. In this totality each bit 

 exists (a) because the whole has an end of value to sub- 

 serve, (b) because the residue of the plan requires precisely 

 this bit to be added to make up the whole. The absence 

 or essential change of this bit must then involve either a 

 modification of the whole, i.e. a change in, if not the total 

 disruption of, its peculiar value, or a corresponding modi- 

 fication of the residual plan. It is in this sense that in 

 any teleological arrangement the parts interact and involve 

 one another. 



2. So far the purpose of the lever, eccentric, or whatever 

 the mechanism be. We have now to observe, secondly, that 

 to the why ' of the process it is equally possible to give an 

 answer on quite different lines. This lever has a recipro- 

 cating motion at the one end and an elliptical motion at the 

 other, because it is screwed into an eccentric and pivoted to 

 a reciprocating rod. The eccentric in turn is rotated by an 



