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THE 



POPULAR SCIENCE 

 MONTHLY. 



JANUARY, 1912 



THE MECHANISTIC CONCEPTION OF LIFE^ 



By JACQUES LOEB 



EOCKEFELLER INSTITUTE FOE MEDICAL EESEAECH 



1. Introductory 

 rriHE reader is aware that two conflicting conceptions are held in 

 -L regard to the nature of life, namely, a vitalistie and a mechan- 

 istic. The vitalists deny the possibility of a complete explanation of 

 life in terms of physics and chemistry. The mechanists proceed as 

 though a complete and unequivocal physico-chemical analysis of life 

 were the attainable goal of biology. It should also be stated that when- 

 ever a vitalist desires to make a contribution to science which is more 

 substantial and lasting than mere argument or metaphor, he forgets or 

 lays aside his vitalism and proceeds on the premises and methods of the 

 mechanist. It is thus obvious that as far as the progress of biology is 

 concerned the difference of viewpoint between vitalists and mechanists 

 is of no consequence. 



The difference between the two opposite views becomes only of 

 importance when the results of biology are applied to ethical and so- 

 ciological problems. Since applications of this kind present them- 

 selves constantly, the biologist may be pardoned if he raises the question 

 whether or not our present state of knowledge justifies the expectation 

 that life phenomena may ultimately be completely explained in terms 

 of physics and chemistry. I intend to put before you a brief survey of 

 some results, in the main recent, of scientific inquiry which I think 

 may be utilized for an answer to this question. 



Before going into these data, it may be necessary to allude briefly 

 to a not uncommon misapprehension in regard to the nature of biolog-. 

 ical " truth " and methods. It is seemingly often taken for granted- 



* Address delivered at the First International Congress of Monists at Ham-^ 

 burg, September 10, 1911. 



