Preface to the First Edition. ix 



With regard to the remarks in the last few paragraphs, 

 prominent exceptions must be made in the case of two recent 

 works at least 1 . The first of these is Professor de Morgan s 

 Formal Logic. He has there given an investigation into the 

 foundations of Probability as conceived by him, and nothing 

 can be more complete and precise than his statement of 

 principles, and his deductions from them. If I could at all 

 agree with these principles there would have been no neces 

 sity for the following essay, as I could not hope to add 

 anything to their foundation, and should be far indeed from 

 rivalling his lucid statement of them. But in his scheme 

 Probability is regarded very much from the Conceptualist 

 point of view ; as stated in the preface, he considers that 

 Probability is concerned with formal inferences in which the 

 premises are entertained with a conviction short of absolute 

 certainty. With this view I cannot agree. As I have entered 

 into criticism of some points of his scheme in one of the 

 following chapters, and shall have occasion frequently to refer 

 to his work, I need say no more about it here. The other 

 work to which I refer is the profound Laws of Thought of 

 the late Professor Boole, to which somewhat similar remarks 

 may in part be applied. Owing however to his peculiar 

 treatment of the subject, I have scarcely anywhere come 

 into contact with any of his expressed opinions. 



The view of the province of Probability adopted in this 

 Essay differs so radically from that of most other writers on 

 the subject, and especially from that of those just referred to, 

 that I have thought it better, as regards details, to avoid all 

 criticism of the opinions of others, except where conflict was 



1 I am here speaking, of course, of History of the Theory of Probability 



those only who have expressly treated being, as the name denotes, mainly 



of the foundations of the science. Mr historical, such enquiries have not 



Todhunter s admirable work on the directly fallen within his province. 



