THE FORCE BEHIND NATURE. 353 



" the antecedents which exerts active force." As this mode of 

 expressing the facts is sanctioned by high authorities at the 

 present time, it may be well for me to explain more fully the 

 basis of my original contention, that our cognition oi force is quite 

 as immediate and direct as our cognition of motion ; in fact (as 

 I think I shall be able to prove), even more fundamental, inas- 

 much as our cognition of matter itself is in great degree dependent 

 upon it. 



It has been recently well said that " all true science involves 

 " both the knowledge of Nature and the knowledge of Man ; it 

 "includes the study of mind, as well as of matter. A philo- 

 " sopher may pursue either, but he can have no complete know- 

 " ledge of what he investigates, without borrowing from the other 

 "department of investigation."* Many of the nature-philo- 

 sophers who affirm that we have no knowledge of anything but 

 the matter and motion which lie within the range of " experience," 

 show themselves very imperfectly acquainted with what "ex- 

 perience " really means ; unhesitatingly ranking as actual objec- 

 tive facts their own mental interpretations of the sensory 

 impressions they receive from external objects. Many meta- 

 physicians, on the other hand, have reasoned as if our concern 

 were with mental operations alone, and as if the abstractions in 

 which they deal had an existence per se, without any relation to 

 the phenomena of nature. But among the ablest thinkers of the 

 present time, there seems to be now a pretty general recognition 

 of the necessity for the replacement of the abstract definitions of 

 metaphysics — so far, at least, as they relate to the external world 

 — by psychological expressions of the modes in which the human 

 ego is affected by its changes. Thus the ordinary metaphysical 

 definition of " matter " is that which possesses " extension." But 

 for this definition to convey any definite idea to our minds, we 

 must know what " extension " means ; and this, we are told, is 

 the " occupation of space." Now, the conception of " space," in 

 the opinion of most psychologists, is ordinarily derived from our 

 interpretation of visual sensations ; and yet these may be alto- 

 gether deceptive. When we look at a window from a short 



* "Natural Theo'iogy of the Doctrine of the Forces." By Professor Ben- 

 jamin Martin, of the University of the City of New York. 



