348 INDUCTION. 



which are not black, and under what conditions we can be justified in 

 regarding this as incredible. 



If there really exist crows which are not black, one of two things 

 must be the fact. Either the circumstance of blackness, in all crows 

 hitherto observed, must be, as it were, an accident, not connected with 

 any distinction of Kind ; or if it be a property of Kind, the crows 

 •which are not black must be a new Kind, a Kind hitherto overlooked, 

 though coming under the same general description by which crows 

 have hitherto been characterized. The first supposition would be 

 jiroved true if we were to discover casually a white crow among black 

 ones, or if it were found tha-t black crows sometimes turn white. The 

 second would be shown to be the fact if in Australia or Central Africa 

 a species or a race of white or gi'ay crows were found to prevail. 



§ 6. The former of these suppositions necessarily implies, that the 

 color is an effect of causation. If blackness, in the crows in which it 

 has been observed, be not a property of Kind, but can be present or ab- 

 sent without any difference, generally, in the properties of the object ; 

 then it is not an ultimate fact in the individuals themselves, but is cer- 

 tainly dependent upon a cause. There are, no doubt, many properties 

 which vary from individual to individual of the same Kind, even the 

 same infima species, or lowest Kind. A flower may be either white 

 or red, without differing in any other respect. But these properties 

 are not ultimate ; they depend on causes. So far as the properties of 

 a thing belong to its own nature, and do not arise from some cause 

 extrinsic to it, they are always the same in the same Kind.* Take, 

 for instance, all simple substances and elementary powers ; the only 

 things of which we are certain that some at least of the properties are 

 really ultimate. Color is generally esteemed the most variable of all 

 properties : yet we do not find that sulphur is sometimes yellow and 

 sometimes white, or that it varies in color at all, except so far as color 

 is the effect of some exti'insic cause, as of the sort of light thrown upon 

 it, the mechanical arrangement of the particles, &c. (as after fusion).. 

 We do not find that iron is sometimes fluid and sometimes solid at the 

 same temperature ; gold sometimes malleable 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 compounds, 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 organized beings (from the extreme complication of 

 the laws by which they are regulated) being more eminently modifi- 

 able, that is, liable to be influenced by a greater number and variety 

 of causes, than any other phenomena whatever; having, moreover, 

 themselves had al)eginning, and therefore a cause; there is reason to 



* I do not here include among properties the accidents of quantity and local position. 

 Every one is aware that no distinctions of Kind can be grounded upon these ; aud that they 

 are incident equally to things of different Kinds and to things of the same. 



