LIFE FROM A PHYSICAL STANDPOINT. 3 



missed the spirits from service. In his Principia he says he 

 framed no hypotheses ; nevertheless he was a great framer of 

 hypotheses, as for instance the corpuscular theory of light 

 which he worked out, and his theory of a necessary ether 

 which he did not work out. So hypotheses are absolutely 

 needful for guidance in all profitable efforts, and as much so in 

 science as anywhere else. Indeed, what is science if not our 

 correlated experiences ? It is interesting to see how men have 

 tried to define it. Buckle says, " Science is a body of generali- 

 zations so irrefragably true, that though they may be covered 

 by subsequent generalizations, can never be overthrown by 

 them." Spencer says, " Science is a higher development of 

 common knowledge." Others say, "Science is classified 

 knowledge." 



Our experiences of all sorts are the subject matter of 

 science, our interpretation of them is our attempt to be logical, 

 our attempt to be scientific, and a true interpretation of any 

 phenomenon will not be inconsistent with any other truth, that 

 is, it will be consistent with all we know and all we can know, 

 so that any hypothesis that is plainly incompatible with the 

 best we know has no place in science. 



So much to clear the way for a proper consideration of life 

 from a scientific standpoint. Some sort of a theory of it is 

 needful for giving direction to research, for if it be a proper 

 subject for investigation the implication is that its explanation 

 will be found to be consistent with what else we know, and if 

 it be not a proper subject, then research is a waste of time. 

 If one assumes that life is some sort of transcendental thing or 

 property not necessarily related to the other things and prop- 

 erties we describe and explain, such an one sets bounds to 

 knowledge on the basis of what he does not know. If on the 

 other hand he is to correlate it with other knowledge, his in- 

 duction must be wide enough to include all phenomena into 

 which life enters in any degree. 



The old theory of a vital force did the former. It assumed 

 that there was in a living thing some sort of an entity 

 capable of directing the functions and that the physical and 

 chemical conditions present were subject to its domination. It 



