i THE VITAL IMPETUS 101 



mutually coordinated elements, but the order is 

 necessarily complete and perfect. It could not be 

 partial, because, once again, the real process which gives 

 rise to it has no parts. That is what neither mechanism 

 nor finalism takes into account, and it is what we also 

 fail to consider when we wonder at the marvellous 

 structure of an instrument such as the eye. At the 

 bottom of our wondering is always this idea, that it 

 would have been possible for a part only of this co 

 ordination to have been realized, that the complete 

 realization is a kind of special favour. This favour the 

 finalists consider as dispensed to them all at once, by the 

 final cause ; the mechanists claim to obtain it little by 

 little, by the effect of natural selection ; but both see 

 something positive in this coordination, and conse 

 quently something fractionable in its cause, something 

 which admits of every possible degree of achievement. In 

 reality, the cause, though more or less intense, cannot 

 produce its effect except in one piece, and completely 

 finished. According as it goes further and further in 

 the direction of vision, it gives the simple pigmentary 

 masses of a lower organism, or the rudimentary eye 

 of a Serpula, or the slightly differentiated eye of the 

 Alciope, or the marvellously perfected eye of the bird ; 

 but all these organs, unequal as is their complexity, 

 necessarily present an equal coordination. For this 

 reason, no matter how distant two animal species may 

 be from each other, if the progress toward vision has 

 gone equally far in both, there is the same visual organ 

 in each case, for the form of the organ only expresses 

 the degree in which the exercise of the function has 

 been obtained. 



But, in speaking of a progress toward vision, are we 

 not coming back to the old notion of finality ? It 



