1$^ THE PHILOSOPHY 



CHAPTER VI. 



Of the Zenfes. 



JN O animal of which we have any knowledge is 

 endowed with more than the five external fenfes of fmelling, 

 tafting, hearing, touch, and feeing ; and no animal, hov;- 

 ever, imperfecSt, is deftitute of the whole. "Without organs 

 of fenfation, in a fmaller or greater number, animal or intel- 

 ledlual exiftence is to us an inconceivable idea. Hence the 

 notion of the aacients, and of a very few moderns, that this 

 earth, as well as all the heavenly bodies, are intelligent be- 

 ings, though they have not the veftige of any inftrument of 

 fenfation, or of any thing analogous to our ideas of animation, 

 except mechanical motion, is too abfurd even to be ferioufly 

 mentioned. 



Upon this interefting fubje^V, as it comprehends every 

 fource of information, and every motive to a6lion in man, as 

 well as in the inferior animals, it is not furprifing that fo 

 much has been written, and that fo many different theories 

 have been invented, and fubmitted to public infpe£lion. 

 Some of thefe theories (liall be taken notice of in a curfory 

 manner, and others, as unworthy of attention, fliall be paiTeci 

 over in filence. 



Our obfervations on the different inftruments of fenfation 

 fhall proceed in the following order, namely, of the fenfes of 

 fmelling, of tafting, of hearing, of touch, and of feeing. In 

 general, it may be remarked, that all fenfation is conveyed 

 to the mind by an unknown influence of the nerves. If the 

 optic, olfactory, or any nerve diftributed over an organ of 

 fenfation, be cut, or rendered paralytic, the animal inftantly 

 lofes that particular fenfe. This is a fa6l univerfally eftab- 

 lifhed by experiment. But that the nerves, which are per- 



