156 FRAGMENTS OF SCIENCE 



is entirely renewed. How is the sense of personal iden- 

 tity maintained across this flight of molecules? To man, 

 as we know him, matter is necessary to consciousness; 

 but the matter of any period may be all changed, while 

 consciousness exhibits no solution of continuity. Like 

 changing sentinels, the oxygen, hydrogen, and carbon 

 that depart, seem to whisper their secret to their com- 

 rades that arrive, and thus, while the Non-ego shifts, 

 the Ego remains the same. Constancy of form in the 

 grouping of the molecules, and not constancy of the 

 molecules themselves, is the correlative of this constancy 

 of perception. Life is a wave which in no two consecu- 

 tive moments of its existence is composed of the same 

 particles. 



Supposing, then, the molecules of the human body, 

 instead of replacing others, and thus renewing a pre- 

 existing form, to be gathered first hand from nature and 

 put together in the same relative positions as those which 

 they occupy in the body. Supposing them to have the 

 self-same forces and distribution of forces, the self-same 

 motions and distribution of motions — would this organ- 

 ized concourse of molecules stand before us as a sentient 

 thinking being? There seems no valid reason to believe 

 that it would not. Or, supposing a planet carved from 

 the sun, set spinning round an axis, and revolving round 

 the sun, at a distance from him equal to that of our 

 earth, would one of the consequences of its refrigeration 

 be the development of organic forms? I lean to the 

 affirmative. Structural forces are certainly in the mass, 

 whether or not those forces reach to the extent of form- 

 ing a plant or an animal. In an amorphous drop of 

 water lie latent all the marvels of crystalline force; 



