376 PHILOSOPHICAL THOUGHT. 



these, such as Sir John Herschel, William Whewell, 

 George Peacock, A. de Morgan, belonged to the Cam- 

 bridge school : they not only aimed at enlarging and 

 deepening the mathematical sciences by introducing the 

 French methods, but they also strove to understand more 

 clearly the logical foundations of the mathematical or 

 exact sciences. They felt the necessity of rewriting the 

 Novum Organum of Bacon. Each of them worked in an 

 independent way at the same task. Herschel published 

 in 1831 his "Preliminary Discourse on the Study of 

 Natural Philosophy," where in a number of examples he 

 showed how the generalisations and discoveries of science 

 were actually arrived at. William Whewell published 

 in 1837 his "History of the Inductive Sciences" as 

 Prolegomena to a " Philosophy of the Inductive Sciences 

 founded upon their History" (1840). Peacock was one 

 of the first who expounded the logical premises of general 

 arithmetic. De Morgan's publications begin in the year 

 1831 with an essay " On the Study and Difficulties of 

 Mathematics," which was followed by a series of writings 

 dealing with the borderland of Logic and Mathematics, 

 such as his essay "On Probabilities" (1838) and his 

 "Logic" (1839). Some of these writings helped to 

 stimulate Mill to the composition of his Logic, the first 

 edition of which appeared in 1843. But there were two 

 other influences which combined to give to Mill's work 

 its representative character, both of which came from 

 his father, James Mill. The first was the Association- 

 psychology to which I referred in the last chapter ; the 

 other was the strong political bias which Mill inherited 

 from his father, as well as from his father's friend, 



