CHAP. XVII.] GENERAL METHOD IN PROBABILITIES. 275 



of events and the algebraic expressions of their values, we shall 

 be led to the same system of practical results. 2ndly, that 

 either of these definitions pursued to its consequences, and con- 

 sidered in connexion with the relations which it inseparably in- 

 volves, conducts us, by inference or suggestion, to the other 

 definition. To a scientific view of the theory of probabilities 

 it is essential that both principles should be viewed together, in 

 their mutual bearing and dependence. 



