Preface to the First Edition. vii 



qualification. Questions might arise in other sciences, in 

 Geology, for example, which could only be answered by the 

 aid of arithmetical calculations. In such a case any one 

 would admit that the arithmetic was extraneous and acci 

 dental. However many questions of this kind there might 

 be here, those persons who do not care to work out special 

 results for themselves might still have an accurate know 

 ledge of the principles of the science, and even considerable 

 acquaintance with the details of it. The same holds true in 

 Probability; its connection with mathematics, though cer 

 tainly far closer than that of most other sciences, is still of 

 much the same kind. It is principally when we wish to 

 work out results for ourselves that mathematical knowledge 

 .s required; without such knowledge the student may still 

 have a firm grasp of the principles and even see his way to 

 many of the derivative results. 



The opinion that Probability, instead of being a branch of 

 ;he general science of evidence which happens to make much 

 use of mathematics, is a portion of mathematics, erroneous as 

 it is, has yet been very disadvantageous to the science in 

 several ways. Students of Philosophy in general have thence 

 conceived a prejudice against Probability, which has for the 

 most part deterred them from examining it. As soon as a 

 subject comes to be considered mathematical its claims 

 seem generally, by the mass of readers, to be either on the 

 me hand scouted or at least courteously rejected, or on the 

 )ther to be blindly accepted with all their assumed conse 

 quences. Of impartial and liberal criticism it obtains little 

 &amp;gt;r nothing. 



The consequences of this state of things have been, I 

 think, disastrous to the students themselves of Probability. 

 No science can safely be abandoned entirely to its own devo 

 tees. Its details of course can only be studied by those who 



