456 Additional Notes. 



mon sense, reason and philosophy, are in a lamentable con- 

 dition when such theories gain ground among men. He who 

 would be a materialist in the nineteenth century, would have 

 been a believer in the doctrine of transubstantiation in the 

 twelfth.* 



Modern Materialists, p. 33. 



The principal materialists of the eighteenth century dif- 

 fered, in some of the details of their opinions, from those 

 philosophers of preceding rimes who held the same gene- 

 ral doctrine. Epicurus supposed the soul of man to be a 

 material substance, but a very refined and attenuated kind of 

 matter. He taught that this substance, notwithstanding the 

 extreme subtlety of its texture, is composed of four distinct 

 parts ; fire, which causes animal heat • an ethereal principle, 

 which is moist vapour; air ; and a fourth principle, which 

 is the cause of sensation. This sentient principle he supposed 

 to differ essentially from the three former, but to be, like the 

 rest, corporeal, because it is capable both of acting and being 

 acted upon by bodies. From the union of the soul, thus 

 constituted, with the body, he believed life and sensation to 

 result. Something like this seems to have been the opinion 

 of almost all the ancient materialists. Spinoza and Hobbes 

 held a system of materialism quite as gross as any of their 

 predecessors; for they seem to have thought that every ma- 

 terial atom is, in a greater or less degree, animated or en- 

 dowed with sensation. Dr. Hartley (if he be ranked in 

 this class, and it is not easy to give him any other place) 

 sometimes appears to recognize a sentient principle, which, if 

 not wholly immaterial, differs from any ideas which he seems 

 to have formed of ordinary matter. Dr. Priestley's opi- 

 nions on this subject, considered as a connected system, are 

 new. He denies that there is any ground for making a dis- 

 tinction between the soul of man and the body ; supposing 

 the whole human constitution to be made up of one homo- 

 geneous substance. He denies that we have any evidence that 

 the Deity himself is immaterial, in die commonly received 

 sense of this word; and, finally, by the adoption of Father 

 Boscovich's theory, he so refines and spiritualizes matter, 

 as to make it an extremely different thing from that gross and 

 impenetrable substance which it is generally represented to be. 

 He differs from preceding materialists, then, in* his views of 



o 



