No. 588] SHORTER ARTICLES AND DISCUSSION 



709 



analogous agent that is e definitione not solely immaterial, but 

 also non-spatial. 



If the entire weight of antivitalistic criticism is directed and 

 concentrated wholly against such ideas as that of Entelechy; 

 and if the mechanist will agree with me that a spatial localiza- 

 tion of a center of forces may be assumed without necessarily 

 combining this with a material bearer, I shall be much gratified. 

 But I fear that this is not the case. The "dynamical prefor- 

 mation of the morphe," as I have elsewhere called the imma- 

 terial but spatial factors of morphogenesis, 9 must, I fear, fall 

 under the same anathema as the classical vitalism. 



To resume the chief postulate of my own "vitalism": if mor- 

 phogenetic investigation is led in a rigorous inductive way to 

 assume a spatial factor at a definite point inside or outside the 

 embryo, no difficulty or contradiction or nonsense arises if no 

 "embryonic" matter, or what is the same, no material "bearer" 

 for this factor can be found at that point. Yet of course no 

 one can be prohibited from forming any sort of hypothesis as 

 to such functionless bearers. It may be even a psychological 

 necessity to form such hypothesis, for we love a ' ' Ding an sich. ' ' 

 But such will form no part of empirical research. 



The right to work with such immaterial factors, and in the in- 

 ductive way set forth above, is, for me, the essence of practical 

 vitalism. 



We have now to examine consequences and postulates de- 

 rived from our fundamental assumption, which seem to present 

 very great difficulty. If we admit a dynamical factor localized 

 in space but not derived from a material bearer, it will be asked, 

 whence comes and how arises this factor? 



The question of causation is based on a postulate of knowledge 

 that can not be eluded; it must be answered in some manner. 



I will attempt to point out briefly how one can think the 

 origin or evolution of such an immaterial morphogenetic factor, 

 although it must be insisted that we have here a problem which 

 does not stand in immediate connection with the purely empir- 

 ical method of investigating the factors considered, so to say, 

 per se in their activity. 



I see no difficulty in assuming an immaterial causality; that 

 is, the arising of an immaterial factor having a certain property 



9 Biologisches Centrablatt, Bd. 32; Archiv. f. Entwicklungsmechanik, Bd. 

 39; Festschrift fUr Schwalbe, 1914. 



