THE BELFAST ADDRESS 149 



compromising antagonism to those who deduced the phe- 

 nomena of nature from the caprices of the gods. They 

 are briefly these: 1. From nothing comes nothing. Noth- 

 ing that exists can be destroyed. All changes are due to 

 the combination and separation of molecules. 2. Nothing 

 happens by chance; every occurrence has its cause, from 

 which it follows by necessity. 3. The only existing things 

 are the atoms and empty space; all else is mere opinion. 



4. The atoms are infinite in number and infinitely various 

 in form; they strike together, and the lateral motions and 

 whirlings which thus arise are the beginnings of worlds. 



5. The varieties of all things depend upon the varieties 

 of their atoms, in number, size, and aggregation. 6. The 

 soul consists of fine, smooth, round atoms, like those of 

 fire. These are the most mobile of all: they interpene- 

 trate the whole body, and in their motions the phenomena 

 of life arise. 



The first five propositions are a fair general statement 

 of the atomic philosophy, as now held. As regards the 

 sixth, Democritus made his finer atoms do duty for the 

 nervous system, whose functions were then unknown. 

 The atoms of Democritus are individually without sensa- 

 tion; they combine in obedience to mechanical laws; and 

 not only organic forms, but the phenomena of sensation 

 and thought, are the result of their combination. 



That great enigma, "the exquisite adaptation of one 

 part of an organism to another part, and to the conditions 

 of life, 7 * more especially the construction of the human 

 body, Democritus made no attempt to solve. Empedocles, 

 a man of more fiery and poetic nature, introduced the no- 

 tion of love and hate among the atoms, to account for 

 their combination and separation; and bolder than De- 



