CO-EXISTENCES INDEPENDENT OF CAUSATION. 411 



vantasje as if, in our inquiries into causation, we were compelled to let in, as 

 one of the possibilities, that the effect may in that particular instance have 

 arisen without any cause at all. 



To overlook this grand distinction was, as it seems to me, the capital 

 error in Bacon's view of inductive philosophy. The principle of elimina- 

 tion, that great logical instrument which he had the immense merit of first 

 bringing into general use, he deemed applicable in the same sense, and in 

 as unqualified a manner, to the investigation of the co-existences, as to that 

 of the successions of phenomena. He seems to have thought that as every 

 event has a cause, or invariable antecedent, so every property of an object 

 has an invariable co-existent, which he called its form ; and the examples 

 he chiefly selected for the application and illustration of his method, were 

 inquiries into such forms ; attempts to determine in what else all those 

 objects resembled, which agreed in some one general property, as hardness 

 or softness, dryness or moistness, heat or coldness. Such inquiries could 

 lead to no result. The objects seldom have any such circumstances in 

 common. They usually agree in the one point inquired into, and in noth- 

 ing else. A great proportion of the properties which, so far as we can 

 conjecture, are the likeliest to be really ultimate, would seem to be inher- 

 ently properties of many different kinds of things not allied in any other 

 respect. And as for the properties which, being effects of causes, we are 

 able to give some account of, they have generally nothing to do with the 

 ultimate resemblances or diversities in the objects themselves, but depend 

 on some outward circumstances, under the influence of which any objects 

 whatever are capable of manifesting those properties ; as is emphatically 

 the case with those favorite subjects of Bacon's scientific inquiries, hotness 

 and coldness, as well as with hardness and softness, solidity and fluidity, 

 and many other conspicuous qualities. 



In the absence, then, of any universal 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 simpli- 

 cem, iibi non reperitur instantia contradictoria. The reason we have for 

 believing that all crows are black, is simply that we have seen and heard of 

 many black crows, and never one of any other color. 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 toward its solution. This, I think, 

 happens in the present instance. The degree of certainty of any generaliza- 

 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 im- 

 probability that crows of any other color should have existed to the pres- 

 ent 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 

 be crows which are not black, and under what conditions we can be justi- 

 fied 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 distinc- 



