2 On certain kinds of Groups or Series. [CHAP. I. 



to be disregarded and even broken up, and an entirely novel 

 arrangement of the objects to be made. In such cases it is 

 the study of the science that first gives the science its unity, 

 for till it is studied the objects with which it is concerned 

 were probably never thought of together. Here a definition 

 cannot be given at the outset, and the process of obtaining it 

 may become by comparison somewhat laborious. 



The science of Probability, at least on the view taken of 

 it in the following pages, is of this latter description. The 

 reader who is at present unacquainted with the science! 

 cannot be at once informed of its scope by a reference 

 objects with which he is already familiar. He will hav 

 to be taken in hand, as it were, and some little tim 

 and trouble will have to be expended in directing h 

 attention to our subject-matter before he can be expected 

 know it. To do this will be our first task. 



2. In studying Nature, in any form, we are continual 

 coming into possession of information which we sum up 

 general propositions. Now in very many cases these gener 

 propositions are neither more nor less certain and accura 

 than the details which they embrace and of which they a 

 composed. We are assuming at present that the truth 

 these generalizations is not disputed; as a matter of fa 

 they may rest on weak evidence, or they may be uncerta 

 from their being widely extended by induction ; what 

 meant is, that when we resolve them into their compone 

 parts we have precisely the same assurance of the truth 

 the details as we have of that of the whole. When I kno 

 for instance, that all cows ruminate, I feel just as certa 

 that any particular cow or cows ruminate as that the who 

 class does. I may be right or wrong in my original stat 

 ment, and I may have obtained it by any conceivable moc 1 

 in which truths can be obtained ; but whatever the value 





