LIMITS OF COMPARATIVE PSYCHOLOGY 723 



preferred, but no methodological test can be allowed to determine 

 a question of fact; nor in the opinion of the speaker can it 

 have the authority of a metaphysical principle. In other words, 

 granting the equal significance of each in its own sphere, the 

 methodological law of simplicity ought not to outweigh the meta- 

 physical law of continuity. 



Evidently, then, the mechanist does not make his point. He has 

 tried to show that unvaried reflex movements are unconscious, but 

 has succeeded only in proving that they may be unconscious, and 

 that it is simplest to conceive them thus. His opponent, how- 

 ever, is not more successful. He has tried to prove that all animal 

 activities are ipso facto conscious; but has shown merely that they 

 may be conscious, and that there is a certain metaphysical support 

 for this conclusion. With regard to organisms whose reactions 

 are unvaried reflexes, it thus appears that neither doctrine is justi- 

 fied on purely scientific grounds. The one proves the possibility 

 that these fixedly reacting animals may be conscious, but does 

 not empirically disprove the possibility of their unconsciousness; 

 and the other empirically proves the possibility that they are un- 

 conscious, but does not disprove the possibility of their conscious- 

 ness. 



It is, however, highly important to observe that this unsettled 

 issue does not concern the animals which make adaptive move- 

 ments. For even the mechanists are agreed that non-mechanical 

 behavior, that is, adaptive reaction to a fixed environment, is a 

 sufficient guarantee of the presence of consciousness. Verworn, 1 

 Bethe, 2 and Loeb 3 unite in admitting this test of consciousness. 

 "Es scheint mir," Bethe says, "der Nachweis ob ein Wesen im 

 Stande ist modificiert zu handeln, der einzige Priifstein zu sein 

 um auf psychische Qualitaten zu schliessen." It is therefore wise 

 to waive the disputed question, does consciousness belong to ani- 

 mals whose reactions are mere fixed reflexes? and to ask, instead, 

 the question, what animals meet that test of consciousness which 

 is admitted by all, in other words, what animals make adaptive 

 reactions ? It is hardly necessary to remark that this argument 

 from the occurrence of adaptive movements constitutes no abso- 

 lute proof of the presence of consciousness, since the argument 

 rests on a mere analogy. Yet the completeness of this analogy of 

 the adaptive animal acts with conscious human movements and 

 the utter absence of an analogy with mechanical processes com- 

 bine to justify the conclusion that animals which act adaptively 

 are conscious. Fortified by the metaphysical argument from con- 



1 Protisten-Studien, pp. 137, 141. 



2 Op. cit., Pfliiger's Archiv, LXX, p. 19. 



3 Comparative Physiology, etc., pp. 12 et al. 



