3S2 



INDUCTION. 



A great proportion of the properties 

 which, so far as we can conjecture, 

 are the likeliest to be really ultimate 

 would seem to be inherently pro- 

 perties of many different Kinds of 

 things, not allied in any other respect. 

 And as for the properties which, be- 

 ing efiFects of causes, we are able to 

 give some account of, they have gene- 

 rally nothing to do with the ultimate 

 resemblances or diversities in the ob- 

 jects themselves, but depend on some 

 outward circumstances, under the in- 

 fluence of which any objects what- 

 ever are capable of manifesting those 

 properties, as is emphatically the case 

 with those favourite subjects of Bacon's 

 scientific inquiries, hotness and cold- 

 ness, as well as with hardness and 

 softness, solidity and fluidity, and 

 many other conspicuous qualities. 



In the absence, then, of any uni- 

 versal law of co-existence, similar to 

 the universal law of causation which 

 regulates sequence, we are thrown 

 back upon the unscientific induction 

 of the ancients, per enumerationem 

 simplicein ubi non reperitur instantia 

 coiitradictoria. The reason we have 

 for believmg that all crows are black 

 is simply that we have seen and heard 

 of many black crows, and never one 

 of any other colour. It remains to 

 be considered how far this evidence 

 can reach, and how we are to measure 

 its strength in any given case. 



§ 5. It sometimes happens that a 

 mere change in the mode of verbally 

 enunciating a question, though nothing 

 is really added to the meaning ex- 

 pressed, is of itself a considerable step 

 towards its solution. This, I think, 

 happens in the present instance. The 

 degree of certainty of any generalisa- 

 tion which rests on no other evidence 

 than the agreement, so far as it goes, 

 of all past observation, is but another 

 phrase for the degree of improbability 

 that an exception, if any existed, could 

 have hitherto remained unobserved. 

 The reason for believing that all crows 

 are black is measured by the impro- 

 \)ability that crows of any other colour 



should have existed to the present 

 time without our being aware of it. 

 Let us state the question in this last 

 mode, and consider what is implied 

 in the supposition that there may ba 

 crows which are not black, and under 

 what conditions we can be justified iu 

 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 de- 

 scription by which crows have hither- 

 to been characterised. The first sup- 

 position 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 grey crows were found to 

 exist. 



§ 6. The former of these supposi- 

 tions necessarily implies that the 

 colour 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 indi- 

 viduals 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 

 ahvavs the same in the same Kind. 



