86 THE POPULAR SCIENCE MONTHLY 



unattainableness, not because the reality of things is unknowable, but because 

 of the innumerable multitude of things knowable. 3 



But even if nature were a limited system and we were able to get 

 into possession of all the conditions under which any event within this 

 system occurs, we should still be no better off, for the external condi- 

 tions under which our imaginary system would be what it is, could 

 never be known. The student of life, of chemistry, of physics land all 

 others, would find their experience hedged in by an impenetrable wall, 

 beyond which they could not go. In an unlimited world, however, there 

 can be no theoretical limit to experience, and while at any time we are 

 actually hedged in by our ignorance, this wall is fortunately capable of 

 being moved by human powers, and the road to further exploration is 

 clear for all who wish to go that way. 



Since exhaustive knowledge in an unlimited universe is clearly 

 unattainable by us, it follows that a scientific explanation is a growing 

 explanation, and of necessity always incomplete. So far as it goes, we 

 have a scientific explanation of life to-day, but it satisfies almost no one 

 because the most important things remain unknown, and our explana- 

 tions are inadequate to meet our practical let alone theoretical needs. 

 These inadequacies have tempted many to fill out with art what they lack 

 in knowledge, but the deficiencies of science, coupled with the certainty 

 that there is no limit in a limitless universe, to what we may find out, 

 to the man who is true to the scientific standard, are the greatest stimuli, 

 for there is no joy equal to that which comes from extending the bounds 

 of knowledge, for even though she tells us nought of " lunar politics," 

 nevertheless, " all the things thou canst desire are not to be compared 

 unto her." 



To many men the realization that the work of science is unending 

 and that she can extend no hope of ultimate explanations, comes as a 

 blow, but this is neither more nor less than the just reward of all who 

 take the universe lightly. This particular limitation biological science 

 chares with all her sisters, for her failure to give us anything else than 

 the physical symbols of life is a shortcoming by no means peculiar to 

 the application of scientific explanations to vital phenomena. The 

 physicist might analyze hydrogen and oxygen with the same magical 

 lens which we applied in imagination to man, and if present opinions 

 are correct, he would see the constellation of electrons that constitute 

 the hydrogen atom and the constellation that makes up the oxygen atom. 

 If he were an experimental physicist, he might take an electron out of 

 the hydrogen atom and replace it by one taken from the oxygen, and be 

 surprised, or not, according to his preconceptions, that substitution 

 makes no difference. Further analysis might tell him that the hydrogen 



2 Brooks, W. K., "Intellectual Conditions for the Science of Embryology," 

 Science, Vol. XV., pp. 453-454. 



V 



