176 READINGS IN BIOLOGICAL SCIENCE 



organization of the egg, will require relatively new principles peculiar to 

 colloid systems, balanced salt solutions, semipermeable membranes, phase 

 boundaries, etc.; but if these "principles" are still found to follow physical 

 and chemical laws, whether the old ones or new ones, for large-scale phe- 

 nomena with \\'hich embryology appears to be concerned, the study of 

 embryology would still come to range itself under a broader conception 

 of natural processes, including in its scope both living and dead material. 

 If, on the other hand, it should turn out that an understanding of living 

 materials calls for something quite new to the physical sciences, it will then 

 be time to examine the nature or un-nature of this something. Meanwhile 

 it seems clear that the next step should be a determined effort to learn 

 all that we can about the kind of system or configfuration that constitutes 

 the tgg. This statement does not mean that we should resort entirely to 

 the kind of analyses which chemists and physicists have invented for the 

 study of their kinds of materials, but that we should not neglect any pos- 

 sible means of penetrating further by experimental methods, on the bi- 

 ological level, into the behavior of such systems. 



It is unsafe to say that the physico-chemical problems are different from 

 the biological problem until we know more about the latter. For it must 

 be obvious to every student of embryology that we have only begun to 

 get information as to the "organization" of the egg on the biological level, 

 and know as yet very Httle about the chemistry and physics of develop- 

 ment. Should it turn out that neither the classical mechanics, nor the new 

 physics suffice, the ground will at least be prepared for the discovery of 

 some new kinds of principles that apply to living things. But until it has 

 been shown that what we call the property or properties of living things 

 are entirely out of line with what is known as non-living systems, it may 

 be short-sighted to resort to obviously metaphysical principles, or even 

 to temporize with them. It is this alternative that separates those whom the 

 philosophers insist on calling mechanists, and those whom the biologists 

 call metaphysicians. There is no need to attempt a compromise by saying 

 that each has his own realm, because the scientist regards mysticism as an 

 outmoded way of attempting to offer a finalistic solution of the problems 

 he studies. 



Most modern biologists are not, however, so much impressed by the idea 

 that there is a principle of life as they are by the great variety of phe- 

 nomena shown by living things. It seems to them premature as well as 

 pretentious to discuss some imaginary ideal property of hfe when there 

 is abundant evidence pointing to the conclusion that there are many prop- 

 erties of living things of many different kinds, each crying out for solution 

 before attempting to synthesize them into life. Of course one may pick 

 out one or more of these, such as consciousness, or purpose, or free will, 

 and make it the si7je qua non of living things, but it should not pass un- 

 noticed that the selection is usually one of the most obscure phenomena of 



