82 



SCIENCE 



[N. S. Vol. XLIV. No. 1125 



THE BASIS OF INDIVIDUALITY IN 



ORGANISMS. A DEFENSE OF 



VITALISM i 



In his presidential address before the 

 Zoological ■ Section of the British Associa- 

 tion for the Advancement of Science, Pro- 

 fessor D'Arcy W. Thompson ('11) said: 



While we keep an open mind on this question of 

 vitalism, or while we lean, as so many of us now 

 do, or even cling with a great yearning, to the be- 

 lief that something other than the physical forces 

 animates the dust of which we are made, it is 

 rather the business of the philosopher than of the 

 biologist, or of the biologist only when he has 

 served his humble and severe apprenticeship to 

 philosophy, to deal with the ultimate problem. It 

 is the plain bounden duty of the biologist to pur- 

 sue his course unprejudiced by vitalistic hypoth- 

 eses, along the road of observation and experiment, 

 according to the accepted discipline of the natural 

 and physical sciences. ... It is an elementary 

 scientific duty, it is a rule that Kant himself laid 

 down, that we should explain, just as far as we 

 possibly can, all that is capable of such explana- 

 tion, in the light of the properties of matter and 

 of the forms of energy with which we are already 

 acquainted. 



This quotation will serve as a text for, 

 and the keynote of, the remarks I shall 

 make this morning. For to Professor 

 Thompson's thesis I heartily subscribe. 

 And if in what I say any statement seems 

 irreconcilable with his assertions, such in- 

 consistency is unintentional and, as I be- 

 lieve, apparent rather than real. But that 

 all will follow me as sympathetically as I 

 assume you have listened to the remarks I 

 have quoted is more than I venture to hope. 



As I interpret the topic under discussion, 

 two main problems are involved : 

 1. The scientific problem of vitalism and 

 mechanism. 



i An address delivered before the American So- 

 ciety of Zoologists and Section P (Zoology) of 

 the American Association for the Advancement of 

 Science at Columbus, Ohio, December 29, 1915, in 

 a symposium upon ' ' The Basis of Individuality 

 in Organisms." 



2. The philosophical problem of idealism 

 and materialism. 



I. THE SCIENTIFIC PROBLEM OF INDIVIDUALITY 

 VITALISM VS. MECHANISM 



The scientific problem of vitalism vs. 

 mechanism has recently been formulated by 

 Jennings ('14, p. 17) as follows: 



"Is individuality a phenomenon not 

 determined by the perceptual conditions, 

 but requiring to account for it the agency 

 of a non-perceptual agent?" To the dis- 

 cussion of this problem we shall first turn. 



The analysis of the concept of individual- 

 ity — at least human individuality — reveals 

 that individuality presents itself in two 

 aspects, distinguishable in thought if not in 

 reality : 



1. The objective or physical aspect of indi- 



viduality ; 



2. The subjective or psychical aspect of 



individuality. 

 Turning our attention, then, to 



1. The Objective or Physical Aspect of 

 Individuality. — In this aspect, the organic 

 individual is a persistent, complex, coherent 

 and spatially-distinct whole, consisting of 

 interdependent parts. The organic indi- 

 vidual is distinguishable from the inorganic 

 individual by the chemical process of pro- 

 teid metabolism, growth by the intussuscep- 

 tion of new material, and by the process of 

 reproduction. In the higher animals and 

 man integration of the highly differentiated 

 body is effected through the mechanism of 

 a central nervous system and the secretions 

 (hormones) of certain glands. As a phys- 

 ical body the organic individual is sub- 

 servient to the laws of sequential mechan- 

 istic causation, and derives all its energy 

 directly or indirectly from the sun. 



2. The Subjective or Psychical Aspect of 

 Individuality. — Each organic individual — 

 at least in the case of man — is directly 

 aware of a series of "states" or "moments" 



