COEXISTENCES INDEPENDENT OF CAUSATION. 383 



Take, for instance, all simple sub- 

 stances and elementary powers ; the 

 only things of which we are certain 

 that some at least of their properties 

 are really ultimate. Colour is gene- 

 rally esteemed the most rariable of 

 all properties ; yet we do not find 

 that sulphur is sometimes yellow and 

 sometimes white, or that it varies in 

 colour at all, except so far as colour 

 is the effect of some extrinsic cause, 

 as of the sort of light thrown upon it, 

 the mechanical arrangement of the 

 particles, (as after fusion,) &c. We 

 do not find that iron is sometim.es 

 fluid and sometimes solid at the same 

 temperature ; gold sometimes malle- 

 able and sometimes brittle ; that 

 hydrogen will sometimes combine 

 with oxygen and sometimes not ; or 

 the like. If from simple substances 

 we pass to any of their definite com- 

 pounds, as water, lime, or sulphuric 

 acid, there is the same constancy in 

 their properties. When properties 

 vary from individual to individual, it 

 is either in the case of miscellaneous 

 aggregations, such as atmospheric air 

 or rock, composed of heterogeneous 

 substances, and not constituting or 

 belonging to any real Kind,* or it is 

 in the case of organic beings. In 

 them, indeed, there is variability in 

 a high degree. Animals of the same 

 species and race, human beings of the 

 same age, sex, and country, will be 

 most different, for example, in face 

 and figure. But organised beings 

 (from the extreme complication of 

 the laws by which they are regulated) 

 being more eminently modifiable, that 

 is, liable to be influenced by a greater 

 number and variety of causes than 

 any other phenomena whatever, hav- 

 ing also themselves had a beginning, 

 and therefore a cause, there is reason 

 to believe that none of their properties 

 are ultimate, but all of them deriva- 



* This doctrine of course asstimes that 

 the allotropic forms of what is chenucally 

 the same substance are so many different 

 Kinds ; and such, in the sense in which 

 the word Kind is used in tiu« treatise, 

 they really «re, 



tive, and produced by causation. And 

 the presumption is confirmed by the 

 fact that the properties which vary 

 from one individual to another also 

 generally vary more or less at different 

 times in the same individual ; which 

 variation, like any other event, sup- 

 poses a cause, and implies, conse- 

 quently, that the properties are not 

 independent of causation. 



If, therefore, blackness be merely 

 accidental in crows, and capable of 

 varying while the Kind remains the 

 same, its presence or absence is doubt- 

 less no ultimate fact, but the effect of 

 some unknown cause ; and in that 

 case the universality of the experience 

 that all crows are black is sufficient 

 proof of a common cause, and estab- 

 lishes the generalisation as an empiri- 

 cal law. Since there are innumerable 

 instances in the affirmative, and 

 hitherto none at all in the negative, 

 the causes on which the property 

 depends must exist everywhere in the 

 limits of the observations which have 

 been made ; and the proposition may 

 be received as universal within those 

 limits, and with the allowable degree 

 of extension to adjacent cases. 



§ 7. If, in the second place, the 

 property, in the instances in which it 

 has been observed, is not an effect of 

 causation, it is a property of Kind ; 

 and in that case the generalisation 

 can only be set aside by the discovery 

 of a new Kind of crow. That, how- 

 ever, a peculiar Kind, not hitherto 

 discovered, should exist in nature, is 

 a supposition so often realised, that it 

 cannot be considered at all improbable. 

 We have nothing to authorise us in 

 attempting to limit the Kinds of 

 things which exist in nature. The 

 only unlikelihood would be that a 

 new Kind should be discovered in 

 localities which there was previously 

 reason to believe had been thoroughly 

 explored ; and even this improbability 

 depends on the degree of conspicuous- 

 ness of the difference between the 

 newly-discovered Kind and all others, 

 since new Kinds of minerals, plants, 



