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SCIENCE 



[N. S. Vol. XXXVII. No. i 



of physical chemistry to a relatively few vital 

 phenomena, do not prove that life and all its 

 manifestations are mechanistic in any but the 

 most general sense of this term, if, indeed, in 

 this way. While a reviewer, then, may not, 

 perhaps, be in a position to take issue with 

 Professor Loeb's specific experiments and re- 

 sults, he may be permitted to make a few com- 

 ments concerning the method which con- 

 ceivably might lead to the establishment of 

 Professor Loeb's broad generalizations, or, at 

 least, would clarify them. 



It would certainly seem, if one wished to 

 demonstrate that life is, or is not, mechanistic 

 in any exact sense, that one should, for ex- 

 ample, state with precision that meaning of 

 this term which is commonly accepted by 

 authorities on mechanics. The term thus 

 defined is, that mechanics is the science of 

 masses moving, and acted upon by forces, in 

 accordance with Newton's laws and the prin- 

 ciples of d'Alembert, of Hamilton and of 

 Lagrange. Having thus defined the term 

 either in this or in some other precise way, 

 one could then ascertain whether the organ- 

 ism has such characteristics as warrant put- 

 ting it in its entirety, or in part, under the 

 conception of mechanism. But Professor 

 Loeb nowhere pursues this method. For his 

 broad generalization, his only real argument, 

 stripped of its rhetorical clothing, is, that, 

 since certain relatively isolated life phenom- 

 ena can be experimented with by the methods 

 of chemistry, physics and physical chemistry, 

 and accounted for by the results of these sci- 

 ences, all life in all of its aspects is mech- 

 anistic. However, it is clear that this con- 

 clusion in any precise sense follows, provided 

 only that chemical, physical and chemical- 

 physical phenomena are themselves mechan- 

 istic in some precise and technical sense of 

 the term. But, whether they are this or not, 

 and, if they are, to what extent, are them- 

 selves questions which are to-day undecided, 

 or, at least, usually not made clear. Vital 

 phenomena do undoubtedly involve chemical 

 and physical processes, but these processes at 

 the present time have themselves not been 

 successfully treated by all the orthodox mech- 



anistic principles. At best one finds physico- 

 chemical phenomena treated only from the 

 standpoint of the law of the conservation of 

 energy and the second law of thermodynamics. 

 However, the criticism which on this ground 

 can be made against Professor Loeb is one 

 that is by no means to be directed against him 

 alone, but can be made a very general one. 

 For the only argument that is usually found 

 among biologists for the mechanistic concep- 

 tion is the one which he presents. In fact, 

 with this the case, it must be said, that really 

 all that most biologists mean by " mechan- 

 istic " is what Professor Loeb means, namely, 

 that which is physical, chemical and physical- 

 chemical, or, more precisely, simply that which 

 is determined or caused. However, there is a 

 more exact scientific meaning of the term in 

 accordance with which it may fairly be asked, 

 if physical and chemical phenomena are ever 

 wholly and exclusively mechanistic. Put with 

 precision, the question is, whether these phe- 

 nomena are wholly and exclusively moving 

 masses acted on by forces, as defined, de- 

 scribed and explained by Newton's laws and 

 the classical principles previously mentioned. 

 Thus stated, the question suggests the broader 

 and more important ones, scientifically and 

 philosophically : Are all the things with which 

 we are acquainted in this universe of ours 

 mechanistic in this precise sense, and, if they 

 are, what does this mean? Does it mean that 

 all phenomena are reducible to masses in 

 motion in the sense that they ultimately con- 

 sist of nothing but these moving masses, or 

 does it mean only that all phenomena are 

 compatihle with the laws of moving masses 

 acted on by forces, but are nevertheless more 

 than motion and masses, even as, for example, 

 physical objects are numerical, but are more 

 than the positive integers with which they are 

 in one-one correspondence? These two con- 

 cepts, " reducible to " and " compatible with," 

 are radically different in their implications, 

 and it is difficult to find either the biologist or 

 the physicist who, holding to the universal 

 applicability of the mechanistic conception, 

 makes them clear. However, if one contends 

 that something, say, the organism, is mech- 



