COEXISTENCES INDEPENDENT OF CAUSATION. 345 



In regard to all eubstances which are ch'emicq,l compoinids, and 

 which tlierefore may be regarded a^ })i-oducts of the juxtaposition of 

 substances different in Kind from themsclvas, there is considerable 

 reason to })resume that the specific properties of the compound are 

 conse(pient, as etiects, upon some of the properties of the elements, 

 although but little progTess has yet been made in tracing any invariable 

 relation between the latter and the former. Still more strongly will a 

 similar presumption exist, when the object itself, as in the case- of 

 organized beings, is no primeval agent, but an efllect, which depends 

 upon»a cause or causes for its very existence. The Kinds therefor'e 

 which are called in chemistry simple substances, or elementary natural 

 agents, are the only ones, any of whose properties can vvith certainty 

 be considered ultimate ; and of these the ultimate properties, are 

 probably much more numerous than we at present recognize, since 

 every successful instance of the resolution of the properties of their 

 compounds into simpler laws, generally leads to the recognition of 

 propei'ties in the elements distinct from any pi-eviously known. The 

 resolution of the laws of the heavenly motions, established the pre- 

 viously unknown ultimate property of a mutual attraction between all 

 bodies : the resolution, so far as it has yet proceeded, of the laws of 

 crystalization, of chemical composition, electricity, magnetism, &c., 

 pouits to various polarities, ultimately inherent in the particles of which 

 bodies are composed ; the comparative atomic weights of different 

 kinds of bodies were ascertained by resolving, into more general laws, 

 the uniformities observed in the proportions in which substances com- 

 bined with one another ; and so forth. Thus although every resolution 

 of a complex uniformity into simpler and more elementary laws has 

 an appai-ent tendency to diminish the number of the ultimate properties, 

 and really does remove many properties from the list; yet (since the 

 result of this simplifying process is to trace up an ever greater variety 

 of different effects to the same agents,) the further we advance in this 

 direction, the greater number of distihct properties we are f(n"ced to 

 recognize^in one and the same (object : the coexistences of which prop- 

 eities must accordingly be ranked among the ultimate generalities of 

 nature. 



§ 3. There are, therefore, only two kinds of propositions which assert 

 an uniformity of coexistence between properties. Either the properties 

 depend on causes, or they df) not. If they do, the proposition which 

 affirms them to be coexistent is a derivative law of coexistence between 

 effects, and until resolved into the laws of causation upon which it 

 depends, is an empirical law, and to be tried by the princij)leH of 

 induction to which such laws are amenable. If, on the other hand, 

 the properties do not depend upon causes, but are ultimate properties; 

 then if it be true that they invariably coexist, they must both be ulti- 

 mate properties of one and the same Kind ; and it is of these only that 

 the coexistences can be classed as a peculiar sort of laws of nature. 



Wlien we affirm that all crows arc; black, or that all negroes have 

 woolly hair, we assert an uniformity of coexistence. We assert that 

 the property of blackness, or of having woolly hair, invariably coexists 

 with the properties which, in common language, or in the scientific 

 classification that we adopt, are taken to constitute the class crow, or 

 the class negro. Now, supposing blackness to be an ultimate property 

 Xx 



