140 On the Campus 



and at least the immediate effect. With secondary or 

 ulterior subjective effects we may not now concern our- 

 selves; but the immediate effect, which is the essential 

 part of the response, is the present subject of our in- 

 quiry. Now inasmuch as in any perception, say as of 

 light or sound, the promoting cause is, as we have seen, 

 physical and physical only, it is impossible for us to con- 

 ceive of the effect in any other light than as physical 

 also; so that when we know that the sense of sight, for 

 instance, is conditioned upon the impact of a certain 

 volume of energy delivered, as we say, in the form of 

 light-waves, it is impossible for us to think of the effect 

 in any other way than as resultant in physical change, 

 displacement of some sort or other, all apart from any 

 mental effects that may or may not be involved in what 

 we recognize as the perception of light. In the sense of 

 taste the approach and reaction are chemical; the form 

 of energy is somewhat different but the response is in 

 both its elements, both in cause and immediate effect 

 something, physical and physical alone. All our percep- 

 tions then have reference to the physical forces by which 

 we are surrounded and all our responses have their ini- 

 tiative in a physical reaction, dependent upon or related 

 to the impinging external force. I who speak to you 

 recognize your presence by the impact on my eyes of one 

 increasing tide of waves that comes up reflected here; 

 you that listen are assailed by yet another tide that in- 

 terrupts not the first ; and the response that is evidenced 

 in your attention, is conditioned upon a physical cause 

 and physical effect, just as really as though I were to toss 



