THEORETIC CONSIDERATIONS 375 



same stimulus by bending to one side. No structural 

 change is evident, so that all we can say is that the physio- 

 logical state of the organism has changed. The same organ- 

 ism in different physiological states reacts differently 

 to the same stimuli. It is evident that the anatomical 

 structure of the organism and the different physical or 

 chemical action of the stimulating agents are not sufficient 

 to account for the reactions. The varying physiological 

 states of the animal are equally important factors. In 

 Stentor we are compelled to assume at least five differ- 

 ent physiological states to account for the five different 

 reactions given under the same conditions." It is thus 

 evident, without further argument, that while there is 

 some evidence bearing on physiological states, we know 

 but little about their nature and regulation. Even in 

 those cases where it appears evident that they are depend- 

 ent upon metabolic processes, it must be said that we 

 know practically nothing about their regulation, since we 

 know almost nothing concerning the fundamentals in 

 metabolism. It is evident, then, that for all that is known 

 to the contrary, subjective factors, entelechies, or psy- 

 choids, factors foreign to inorganics, may have a hand in 

 controlling physiological changes and consequently the 

 reactions. Such factors have been postulated by the vital- 

 ists and neovitalists, notably by Hans Driesch. 



Driesch postulated a non-energetic factor to account for 

 form regulation and regulation in behavior. He claims 

 that if certain organisms, starfish eggs, for instance, are 

 divided into halves in any direction, each half will produce 

 a new individual. Such organisms, he says, form harmo- 

 nious equipotential systems. Every part has the same 

 potency (future possibilities) as every other part, no 

 matter how the whole is divided. No machine^ (using 

 the term in its broadest sense), he holds, could account for 



^ "A machine is a typical configuration of physical and of chemical 

 constituents, by the acting of which a typical effect is attained." (Driesch, 

 Vol. I, pp. 138, 139.) 



