102 CREATIVE EVOLUTION ichap. 



circumstances are forces evolution must reckon with, 

 another to claim that they are the directing causes of 

 evolution. This latter theory is that of mechanism. It 

 excludes absolutely the hypothesis of an original impetus, 

 I mean an internal push that has carried life, by more and 

 more complex forms, to higher and higher destinies. Yet 

 this impetus is evident, and a mere glance at fossil species 

 shows us that life need not have evolved at all, or might 

 have evolved only in very restricted limits, if it had chosen 

 the alternative, much more convenient to itself, of be- 

 coming anchylosed in its primitive forms. Certain Fora- 

 minifera have not varied since the Silurian epoch. Un- 

 moved witnesses of the innumerable revolutions that have 

 upheaved our planet, the Lingulae are to-day what they 

 were at the remotest times of the paleozoic era. 



The truth is that adaptation explains the sinuosities of 

 the movement of evolution, but not its general directions, 

 still less the movement itself. 1 The road that leads to 

 the town is obliged to follow the ups and downs of the hills; 

 it adapts itself to the accidents of the ground; but the 

 accidents of the ground are not the' cause of the road, nor 

 have they given it its direction. At every moment they 

 furnish it with what is indispensable, namely, the soil on 

 which it lies; but if we consider the whole of the road, in- 

 stead of each of its parts, the accidents of the ground appear 

 only as impediments or causes of delay, for the road aims 

 simply at the town and would fain be a straight line. Just 

 so as regards the evolution of life and the circumstances 

 through which it passes — with this difference, that evo- 

 lution does not mark out a solitary route, that it takes 

 directions without aiming at ends, and that it remains 

 inventive even in its adaptations. 



1 This view of adaptation has been noted by M. F. Marin in a re- 

 markable article on the origin of species, "L'Origine des especes" 

 (Revue scientifique, Nov. 1901, p. 580). 



