IOWA ACADEMY OF SCIENCES* 1 97 



appear to have definite purposes, to form plans and act upon 

 them, both intelligently and rationally. 



Again, it may be urged that the focal and marginal inter- 

 grade so completely that it is impossible as a matter of fact to 

 distinctly separate them in consciousness. For example, 

 I say that a certain person in this room becomes focal in my 

 consciousness. This is inexact because, perhaps, I see only a 

 small part of that person, perhaps the head and shoulders; or 

 my attention may be fixed on his eyes alone and all the rest 

 may be focal. In practice, then, it is almost impossible to sepa- 

 the marginal from the focal, just as it would be almost impossi- 

 ble to discriminate exactly between the crest and body of a 

 wave We know in general what is meant by the terms, but 

 the one blends completely with the other as an actual fact. 

 But this distinction between marginal and focal is the very 

 thing upon which Morgan bases his denial of reasoning to the 

 brutes. He says that in animals the relation is marginal, but 

 never becomes focal. How can he assert this thus positively 

 when focal and marginal denote completely interblending parts 

 of the wave of consciousness? How can he maintain his position 

 in the face of the fact that in actual practice we cannot clearly 

 distinguish the two? 



To sum up the argument. 



First. — The canon of Morgan appears to be an unjust and 

 inexact law for the comparison of mental phenomena by these 

 physical manifestations in conduct because it ignores the mul- 

 titude of homologies that exist between man and the higher 

 mammalia. 



Second. — These homologies should justify us in assuming 

 that like activities in man and mammals are indices of like 

 mental causes to psychological processes, unless we have 

 independent evidence to the contrary. 



Third. — Experience and observation prove that that which is 

 marginal in consciousness may become focal in both man and 

 animals. If this be true the burden of proof rests with those 

 who say that one particular kind of marginal impression never 

 becomes focal in mammals lower than man. 



Fourth.— The psychology of dreams may furnish an example 

 of mental activity which is composed of sense impressions or 

 reinstatements without the relations becoming focal. Animals 

 do not act as if dreaming, but show continuity both of conduct 

 and of purpose. 



