[ 37 1 ] 
circumftances, it has happened a certain number of 
times, and failed a certain other number of times. 
He adds, that he foon perceived that it would not be 
very difficult to do this, provided fome rule could be 
found according to which we ought to eftimate the 
chance that the probability for the happening of an 
event perfectly unknown, fhould lie between any two 
named degrees of probability, antecedently to any ex- 
periments made about it ; and that it appeared to him 
that the rule muff be to fuppofe the chance the fame 
that it fhould lie between any two equidifferent.de- 
grees ; which, if it were allowed, all the reft might 
be eafily calculated in the common method of pro- 
ceeding in the dodtrine of chances. Accordingly, I 
find among his papers a very ingenious folution of this 
problem in this way. But he afterwards confidered, 
that the populate on which he had argued might not 
perhaps be looked upon by all as reafonable j and 
therefore he chofe to lay down in another form the 
propofition in which he thought the folution of the 
problem is contained, and in a Jcholiwn to fubjoin the 
reafons why he thought fo, rather than to take into 
his mathematical reafoning any thing that might ad- 
mit difpute. This, you will obferve, is the method 
which he has purfued in this effay. 
Every judicious perfon will be fenfible that the 
problem now mentioned is by no means merely a 
curious {peculation in the dodtrine of chances, but ne- 
ceffary to be folved in order to a fure foundation foi all 
our reafonings concerning paft fadts, and what is likely 
to be hereafter. Common fenfe is indeed lufficient 
to fhew us that, from the oblervation of what has in 
former inftances been the confequence of a certain 
c ‘ caufe 
