LIMITS OF COMPARATIVE PSYCHOLOGY 719 



larity of conduct is added likeness of structure. So Binet 1 describes 

 the ocular spot of a ciliated infusory," composed of a convex crys- 

 talline humor, having the form of a watch-crystal enveloped by 

 pigment," and concludes that the "identity of structure" with that 

 of the eyes of higher animals "naturally leads to the assumption of 

 the identity of functions." 



An examination of these arguments discloses, however, certain 

 flaws, of which the more significant are the following: In the first 

 place, the law of continuity proves too much. If the sudden ap- 

 pearance of consciousness at any stage of organic development 

 be irrational, so also is the sudden appearance of consciousness 

 at any point of development inorganic as well as organic. Con- 

 sciousness must, in other words, be attributed to vegetable as well 

 as to animal organisms, and must be claimed also, on this same 

 principle, for inorganic matter: it must be attributed to the iron- 

 filings attracted by the magnet, no less than to the infusoria at- 

 tracted by the food. 



The chief objection to the empirical argument of the continuity 

 theory is less readily stated in a compact form. The argument, 

 it will be remembered, rests on the analogy of such acts as the move- 

 ments of bacteria to the light or the hiding of young gulls in the 

 crevices of rocks, with corresponding acts of human beings, which 

 it is assumed are consciously performed. But this assump- 

 tion is obviously in fault, as far as individual human acts are con- 

 cerned. Motions even more complicated for example, the avoid- 

 ance of obstacles in walking and the muscular contractions neces- 

 sary to a musical performance may be unconsciously performed 

 by human beings; and the mere likeness with human movements 

 cannot, then, prove animal actions to be conscious. To rescue 

 the analogy, modern upholders of the continuity theory therefore 

 make a further hypothesis. They admit that even complex human 

 acts may be unconsciously performed, but they conceive all such acts 

 as habitual, and they assume that all habitual movements were 

 originally performed with consciousness and that they have grown 

 unconscious with practice. 2 Many of these unconscious human 

 movements may be traced back, it is shown, to consciously per- 

 formed acts in the past life of the individual. Others, for example 

 the characteristic bodily expressions of emotion, have remained 

 unconscious throughout individual experience, but these, it is 

 urged, were consciously performed by the animal ancestors of the 

 human being: in a word, they have grown unconscious through 

 racial experience. 



1 Op. tit., p. 28. 



2 Cf. Spencer, Principles of Psychology, vol. n, part ix, chap, iv, pp. 546 seq.; 

 Wundt, Grundriss, 6th edition, iv, sec. 19, p. 339; Schneider, op. tit., v, pp. 150- 

 155; E. B. Titchener, Pop. Sti. Mo., vol. LX, pp. 465-467, 1902. 



