COSMIC PHILOSOPHY 



from a single instance ; a universal proposition 

 from a singular one. Now mark another case, 

 and contrast it with this. Not all the instances 

 which have been observed since the beginning 

 of the world, in support of the general proposi- 

 tion that all crows are black, would be deemed 

 a sufficient presumption of the truth of the 

 proposition, to outweigh the testimony of one 

 unexceptionable witness who should affirm that 

 in some region of the earth not fully explored, 

 he had caught and examined a crow, and had 

 found it to be gray." 



What is the explanation of this difference ? 

 " Why is a single instance in some cases suffi- 

 cient for a complete induction, while in others 

 myriads of concurring instances, without a single 

 exception known or presumed, go such a very 

 little way towards establishing a universal pro- 

 position ? " The solution is to be sought in the 

 extreme complexity of the conditions in the 

 one case as contrasted with their extreme sim- 

 plicity in the other. The scientific thinker does 

 not consider blackness a necessary attribute of 

 a crow, because he believes that some inappre- 

 ciable variation in the nutrition of the bird, by 

 altering the deposit of pigment in the feathers, 

 might give us a gray or a white crow instead of 

 a black one. Or if we do not reflect upon the 

 matter so carefully as this, we at least regard a 

 crow as a very complex aggregate of conditions 

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