V GENERAL REFLECTIONS AND CONCLUSIONS 291 



and physical terms, exists as must exist in development. This 

 entity is not a form of energy but a vital constant, analogous 

 to the constants or ultimate conceptions of mechanics and physics 

 and chemistry and crystallography, but not reducible to these, 

 just as these cannot be translated into one another. Driesch 

 describes it as rudimentary feeling and willing, as a ' psychoid \ 

 as ' morphaesthetic ', or perceptive of that form which is the 

 desired end towards which it controls and directs all the material 

 elements of differentiation. Its activities are thus verae causae 

 unconditional and invariable antecedents psychical factors which 

 can intervene in the purely physical series of causes and effects, 

 and for it he revives the Aristotelian term c Entelechy '. Such 

 is the ' vitalism ' introduced by Hans Driesch, a teleological 

 theory clearly, but not the ' static ' teleology of the AnalyliscJte 

 T/teorie ; rather it is a ' dynamic ' teleology which not only sees 

 an end in every organic process but postulates an immaterial 

 entity to guide the merely mechanical forces towards the realiza- 

 tion of that end. 



This theory would seem to be open to serious criticism, and 

 from two sides, the scientific and the philosophical. 



In the first place, we must remind Driesch that on his own 

 showing a comparatively simple structure is all that is necessary 

 to form the starting-point of a developmental process, however 

 complex that may be, and that there is no reason why such a 

 structure should not be divisible into portions, each of which will 

 possess all the parts of the structure in correct proportions, and 

 be therefore totipotent. But such division cannot continue 

 indefinitely, for as we know, and as Driesch knows too, there is 

 always, sooner or later, a restriction of potentialities, and this is 

 due to the manner of distribution ab origine of the constituent parts 

 of the whole. When Driesch asserts that this restriction is due 

 to size alone, to mere lack of material, and not lack of specific 

 material, when he tells us that the blastomeres can be dislocated 

 indefinitely without prejudice to a normal development, when he 

 exclaims that ( Jedes jedes kann ', he is manifestly led away by 

 the reaction against the theory of the preformation of as many 

 units as there are inheritable characters on the one hand, and 

 on the other by his own erroneous presuppositions as to the con- 



u a 



