THE MECHANICAL SYSTEM AND ITS LIMITS 365 



without there being any aim that influences the whole 

 series. What often seems to us to be the goal or end 

 of the series is only a link in it, followed uninterruptedly 

 by other links. Thus, for instance, the construction of 

 a living thing from the ovum is not a halting-place in 

 the series of causes ; they continue their endless course 

 beyond it. 



But in teleological causality there is such a thing as an 

 end or purpose. It is true that here also cause and 

 effect follow necessarily on each other, but the end has 

 the power of attracting causes and effects to itself so that 

 they do not run beyond but realise it. According to the 

 teleological view the construction of an organism is the 

 end which the whole embryonic development is aiming to 

 realise. The end, as it were, observes and controls the 

 series of causes, and is realised in the ultimate effect. 

 The very first causes were controlled by a fact that was 

 still in the future. The ordinary causes, which we have 

 discussed, can only produce an effect when they them- 

 selves have already been brought into existence as an 

 effect. Teleological causes or ends act before they are 

 themselves realised. 



We rejected in the previous chapter the notion that 

 organisms aim at the realisation of ends. Seeking an 

 end would be the greatest conceivable form of purposive- 

 ness. But the rudimentary organs, the erratic instincts, 

 and the many imperfections in nature prove that the 

 evolution of animals is not wholly controlled by pur- 

 posiveness. Moreover, how is it that an end is merely 

 sought in some animals and realised in others? We 



