iv PARALLELISM AND MONISM 375 



tells us nothing of the kind. It shows us the inter 

 dependence of the mental and the physical, the necessity 

 of a certain cerebral substratum for the psychical state, 

 nothing more. From the fact that two things are mutu 

 ally dependent, it does not follow that they are equiva 

 lent. Because a certain screw is necessary to a certain 

 machine, because the machine works when the screw is 

 there and stops when the screw is taken away, we do not 

 say that the screw is the equivalent of the machine. For 

 correspondence to be equivalence, it would be necessary 

 that to any part of the machine a definite part of the 

 screw should correspond as in a literal translation in 

 which each chapter renders a chapter, each sentence a 

 sentence, each word a word. Now, the relation of the 

 brain to consciousness seems to be entirely different. 

 Not only does the hypothesis of an equivalence between 

 the psychical state and the cerebral state imply a down 

 right absurdity, as we have tried to prove in a former 

 essay, 1 but the facts, examined without prejudice, cer 

 tainly seem to indicate that the relation of the psychical 

 to the physical is just that of the machine to the screw. 

 To speak of an equivalence between the two is simply 

 to curtail, and make almost unintelligible, the Spinozis- 

 tic or Leibnizian metaphysic. It is to accept this philo 

 sophy, such as it is, on the side of Extension, but to 

 mutilate it on the side of Thought. With Spinoza, 

 with Leibniz, we suppose the unifying synthesis of the 

 phenomena of matter achieved, and everything in matter 

 explained mechanically. But, for the conscious facts, 

 we no longer push the synthesis to the end. We stop 

 half-way. We suppose consciousness to be coextensive 



1 &quot; Le Paralogisme psycho-physiologique &quot; (Revue de m/taphysique et de 

 morale, Nov. 1904, pp. 895-908). Cf. Matttre et mfmoire, Paris, 1896, 

 chap. i. 



