RELATION TO PSYCHIC BEHAVIOR 329 



jective states. This has the additional ground that the ideal of most 

 scientific men is to explain behavior in terms of matter and energy, so 

 that the introduction of psychic implications is considered superfluous. 



While this exclusive use of objective terms has great advantages, it 

 has one possible disadvantage. It seems to make an absolute gulf be- 

 tween the behavior of the lower organisms on the one hand, and that of 

 man and higher animals on the other. From a discussion of the be- 

 havior of the lower organisms in objective terms, compared with a dis- 

 cussion of the behavior of man in subjective terms, we get the impression 

 of complete discontinuity between the two. 



Does such a gulf actually exist, or does it lie only in our manner of 

 speech? We can best get evidence on this question by comparing the 

 objective features of behavior in lower and in higher organisms. In 

 any animal outside of man, and even in man outside of the self, the 

 existence of perception, choice, desire, memory, emotion, intelligence, 

 reasoning, etc., is judged from certain objective facts — certain things 

 which the organisms do. Do we find in the lower organisms objective 

 phenomena of a similar character, so that the same psychic names would 

 be applied to them if found in higher organisms? Do the objective 

 factors in the behavior of lower organisms follow laws that are similar 

 to the laws of psychic states ? Only by comparing the objective factors 

 can we determine whether there is continuity or a gulf between the be- 

 havior of lower and higher organisms (including man), for it is only 

 these factors that we know. 



Let us then examine some of the concepts employed in discussions 

 of the behavior of higher animals and man, determining whether there 

 exist any corresponding phenomena in lower organisms. We shall not 

 attempt to take into consideration the scholastic definitions of the terms 

 used, but shall judge of them merely from the objective phenomena on 

 which they are based. 



When we say that an animal perceives something, or that it shows 

 perception of something, we base this statement on the observation that 

 it reacts in some way to this thing. On the same basis we could make 

 the statement that Amoeba perceives all classes of stimuli which we our- 

 selves perceive, save sound (which is, however, essentially one form of 

 mechanical stimulation). Perception as judged from our subjective 

 experiences means much more: how much of this may be present in 

 animals outside the self we cannot know. 



Discrimination is a term based, so far as objective evidence goes, 

 upon the observed fact that organisms react differently to different 

 stimuli. In this sense Paramecium, as we have seen, discriminates 

 acids from alkalies ; Amoeba discriminates a Euglena cyst from a grain 



