x Preface to the First Edition. 



unavoidable. With regard to that radical difference itself 

 Bacon s remark applies, behind which I must shelter myself 

 from any change of presumption. &quot;Quod ad universalem 

 istam reprehensionem attinet, certissimum vere est rem re- 

 putanti, earn et magis probabilem esse et magis modestam, 

 quam si facta fuisset ex parte.&quot; 



Almost the only writer who seems to me to have ex 

 pressed a just view of the nature and foundation of the rules 

 of Probability is Mr Mill, in his System of Logic 1 . His 

 treatment of the subject is however very brief, and a consi 

 derable portion of the space which he has devoted to it is 

 occupied by the discussion of one or two special examples. 

 There are moreover some errors, as it seems to me, in what 

 he has written, which will be referred to in some of the 

 following chapters. 



The reference to the work just mentioned will serve to 

 convey a general idea of the view of Probability adopted in 

 this Essay. With what may be called the Material view of 

 Logic as opposed to the Formal or Coriceptualist, with that 

 which regards it as taking cognisance of laws of things and 

 not of the laws of our own minds in thinking about things, 

 I am in entire accordance. Of the province of Logic, regarded 

 from this point of view, and under its widest aspect, Proba 

 bility may, in my opinion, be considered to be a portion. The 

 principal objects of this Essay are to ascertain how great a 

 portion it comprises, where we are to draw the boundary be 

 tween it and the contiguous branches of the general science 



1 This remark, and that at the Probability. I have given a pretty 



Gommencement of the last paragraph, full discussion of the general prin- 



having been misunderstood, I ought ciples of this view in the tenth 



to say that the only sense in which chapter, and have there pointed out 



originality is claimed for this Essay some of the peculiarities to which it 



is in the thorough working out of the leads. 

 Material view of Logic as applied to 



