480 GENERAL REFLECTIONS ON 



mals are all distinguished from man, by having no imma- 

 terial agent connected with their bodies. This opinion has 

 two branches, the most improbable of which has been 

 adopted by no less men than Bacon, Locke, Gassendi and 

 Willis. It is that the sentient principles of brutes are 

 wholly material. As Willis was the only one of these ce- 

 lebrated persons who had any pretensions to be a Zo- 

 ologist, he is the only one that can be charged with incon- 

 sistency. When he admitted the existence of an immate- 

 rial soul in man, he must have considered the medullary 

 matter to be an instrument, or medium only. Now if 

 nerves be the instrument or medium in one case to produce 

 certain effects, it is almost inconceivable, and certainly in 

 opposition to the established rules of philosophy, that they 

 should be the causes of the same effects in another. If 

 medullary matter in man be acted upon by an immaterial 

 agent, and brutes be allowed the faculty of perception, 

 the nerves of these must also be acted upon by an im- 

 material agent, unless indeed we make all the lower animals, 

 as materialists apparently make man, to consist each of 

 an infinite number of sentient beings. 



In order to avoid this absurdity, Descartes and Male- 

 branche denied to animals the faculty of perception. This 

 is the second branch of that theory which allows no im- 

 material agent to act on the nerves of the lower animals. 

 It is said to have been borrowed by the Cartesian school, 

 from Vivez and Pereira, but it is probably still more an- 

 cient. Descartes was too good a catholic not to make the 

 human soul an immaterial being, attendant during this life 

 on the body ; and too proud probably of the powers of his 

 own mind to believe in the existence of any similar prin- 

 ciple in brutes. He thus came to view them as mere ma- 



