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The aSI'ive, efficient caiifes of events are thus enumerated in the 

 Ethics of Ariftotle, " the feveral caufes appear to be nature, ne- 

 '.' ceffity, and chance, and befides thefe, mind or intelled, and 

 " whatever operates by or through man." L. 3. c. 3. Chance 

 therefore is an adive, efficient caufe ; but it is 2X^0 an accidental 

 caiife, " ad caufam per accidens revocatur fortuna et cafus," Burgefd. 

 Chance therefore is an efficient, accidental caufe of an event. 



The probability of an event, according to De Moivre and Simpfon, 

 is greater or lefs according to the number of chances by which it 

 may happen, compared with the whole number of chances by 

 which it may either happen or fail. 



As, fuppofing it were required to exprcfs the probability of 

 throwing either an ace or duce at the firft throw with a fingle die; 

 then there being in all 6 diifercnt chances or ways that the die 

 may fall, and only 2 of them for the ace or duce to come upward, 

 the probability of the happening of one of thefe will be | or -L. 



Wherefore if we conftitute a fradion, whereof the numerator 

 fhall be the number of chances whereby an event may happen, 

 and the denominator the number of chances whereby it may either 

 happen or fail,- that fradion will be a proper exponent of the pro- 

 bability of happening. 



For 



