214 ANIMAL AUTOMATISM. [LECT. 



of the high probability, that every molecular change 

 which gives rise to a state of consciousness, leaves a 

 more or less persistent structural modification, through 

 which the same molecular change may be regenerated 

 by other agencies than the cause which first pro- 

 duced it. 



Thus far, the propositions respecting the physiology 

 of the nervous system which are stated by Descartes 

 have simply been more clearly defined, more fully 

 illustrated, and, for the most part, demonstrated, by 

 modern physiological research. But there remains a 

 doctrine to which Descartes attached great weight, so 

 that full acceptance of .it became a sort of note of a 

 thorough-going Cartesian, but which, nevertheless, is 

 so opposed to ordinary prepossessions that it attained 

 more general notoriety, and gave rise to more discus- 

 sion, than almost any other Cartesian hypothesis. It 

 is the doctrine, that brute animals are mere machines 

 or automata, devoid not only of reason, but of any 

 kind of consciousness, which is stated briefly in the 

 "Discours de la Methode," and more fully in the 

 "Keponses aux Quatriemes Objections," and in the 

 correspondence with Henry More. 1 



The process of reasoning by which Descartes 

 arrived at this startling conclusion is well shown in 

 the folio wing passage of the " Keponses:" 



" But as regards the souls of beasts, although this is not the 



1 "Keponse de M. Descartes a M. Moras." 1649. " CEuvres," 

 tome x. p. 204. " Mais le plus grand de tous les prejuges que nous 

 ayons retenus de notre enfance, est celui de croire que les betes 

 pensent," etc. 



