AND ITS SELF-CONSERVATIOK. 27 



assumed at the same time, by the same group of particles, 

 it can be true only in a special sense. If true in the same 

 sense it can be only in different times. At the moment 

 when the particles constitute diamond in reality, they can 

 at that moment be said to constitute not-diamond (woody 

 fiber, coal, etc.) only in the sense of potentiality. Or, in 

 general terms, any given quantity of matter can be in one 

 and only one state at one and the same time; so that, 

 whatever the number of states possible for such given 

 quantity of matter, those states can be realized by and for 

 it only serially, or through successive periods of time. 



Thus the law of contradiction might also be called the 

 law of consistency as exhibited in the actual world the 

 law of precision in the modes of existence. 



It would seem then that the true significance of the law 

 of contradiction is rather this: First, that whatever the 

 forms successively assumed by any portion of substance, 

 that portion of substance, through whatever transforma- 

 tions it may pass, still exists absolutely, and is wholly 

 excluded from non-existence in the sense of mere nothing- 

 ness; secondly, throughout its transformations a given 

 portion of substance can as a unit assume at any given 

 moment but one consistent grouping of its parts, from 

 which it follows that no two contrary descriptions could 

 be true of it at the same time. It is perfectly consistent 

 with our conception of the existent that it should assume 

 all possible forms of existence; but it is wholly inconsist- 

 ent with that conception to suppose that the existent 

 in any of its possible aspects should ever become utterly 

 null or non-existent. 



It is to be noted, too, that while the law of identity 

 would seem on first view to exclude change, and while it 



