412 INDUCTION. 



tion 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 

 chaiMcterized. The first supposition would be proved true if we were to 

 discover casually a white crow among black ones, or if it were found that 

 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 gray 

 crows were found to exist. 



§ 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 absent without 

 any difference generally in the properties of the object, then it is not an 

 ultimate fact in the individuals themselves, but is certainly dependent on 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. Some flowers 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 their 

 properties are really ultimate. Color is generally esteemed the most varia- 

 ble 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 extrinsic cause, as of the sort of light thrown upon it, 

 the mechanical ai*rangement of the particles (as after fusion), etc. We do 

 not find that iron is sometimes fluid and sometimes solid at the same tem- 

 perature ; 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 proper- 

 ties. 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 differ- 

 ent, for example, in face and figure. But organized beings (from the ex- 

 treme 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 ; having also 

 themselves had a beginning, and therefore a cause ; there is reason to be- 

 lieve that none of their properties are ultimate, but all of them deriva- 

 tive, and produced by causation. And the jDi'esumption 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, supposes a cause, and implies, consequently, 

 that the properties are not independent of causation. 



If, therefore, blackness be merely accidental in crows, and capable of 



* This doctnne of course assumes that the allotropic forms of what is chemically the same 

 substance are so many different Kinds ; and such, in the sense in which the word Kind is 

 used in this treatise, they really are. 



