April 17, 1914] 



SCIENCE 



553 



emplified by our own conscious voluntary 

 activities. We deliberate, plan and choose. 

 It seems to us as if certain things and oc- 

 currences in the world were due to these 

 our plans and choices, and are different 

 from what they would be were our will not 

 a factor in the world-process. On the other 

 hand, some things and events in the nat- 

 ural world — notably the recurrent move- 

 ments of the heavenly bodies, and the proc- 

 esses which attend the workings of ma- 

 chines, seem to us to be, in some or in 

 many respects essentially different from 

 the processes which result from our plans, 

 our choices and our voluntary deeds. 

 What is called a mechanical theory of na- 

 ture, or, more generally still, materialism, 

 undertakes to account for the vital proc- 

 esses, for the activities of organisms, by 

 supposing that they too are not essentially 

 different from the other material processes, 

 and that they really exemplify the same 

 natural laws which the movements of the 

 heavenly bodies and the workings of ma- 

 chines illustrate. 



The contrast between vitalism and ma- 

 terialism is, in the history of science and 

 of philosophy, very ancient. The Greeks 

 began with doctrines which were, in a 

 somewhat confused way, both materialistic 

 and vitalistic. The natural world was 

 viewed as, in one of its aspects, a sort of 

 machine, a chariot whose mechanical move- 

 ment was an essential feature of its very 

 being. The natural world was also re- 

 garded as through and through alive — a 

 world of love and strife, of mixing and of 

 sundering, of wisdom and of something re- 

 sembling contrivance. 



To this early Greek vitalism, which had 

 various forms, the materialism of Demoe- 

 ritus opposed a mechanical theory of na- 

 ture which was much more ingenious and 

 considerate than were the earliest forms in 



which the machine-like aspect of nature 

 was described. On the whole, however, 

 vitalism, the doctrine that nature acts not 

 in vain, but in an essentially planful and 

 designing way, was predominant in Greek 

 thought. 



The greatest Greek vitalist was Aristotle. 

 Materialism remained in the background 

 of ancient thought, and was destined to be 

 revived, and to take on the form of the 

 modern mechanical theory of nature, only 

 after the beginnings of the new science in 

 the seventeenth century of our era. 



These ancient problems as to whether 

 nature is rather a mechanism or an expres- 

 sion of something which essentially involves 

 or resembles wisdom and contrivance, are 

 certainly not questions which belong to any 

 one natural science or group of natural 

 sciences. From time to time, however, they 

 come nearer to the surface of popular or of 

 scientific discussion. The present is a 

 moment when a certain interest in various 

 forms of vitalism has once more become 

 prominent in the discussions not only of 

 philosophers and of leaders in popular in- 

 quiry, but of some professional students of 

 the natural sciences of life as well. 



I do not know how far it will prove to be 

 interesting or profitable for you, as scien- 

 tific men, to discuss, in your future meet- 

 ings, if you have any future meetings, 

 problems directly connected with vitalism, 

 or with its old opponent, the mechanistic 

 theory of the nature of life. I know only 

 that when we mention such problems we 

 call attention to one of the ancient boun- 

 dary lines, or, as one may say, to one of the 

 beaches where, in the realms of inquiry, 

 sea and land come face to face with each 

 other; so that two widely contracting 

 realms of nature here seem to clash. Here, 

 then, the waves of experience tumble, and 



