4 ESSAY ON PROBABILITIES. 



such it is) remain ; we are not here considering what is 

 the proper measure, but whether we can conceive the 

 possibility of a measure or not. Let the preceding me- 

 thod of measurement be admitted ; and let us ask how 

 we stand with regard to the same assertion, predicated 

 of one or other of a million of children born together. 

 The answer is, we feel quite certain, that many of them 

 will die at the age of 50. Supposing humanity to en- 

 dure 50 years, we feel as confident of the truth of the 

 assertion, as we do that Rome was taken by Alaric, or 

 that fire will burn. Without entering into the very 

 different sources through which conviction comes to us, 

 we put four propositions together : 



and, we ask, if you were to receive a certain advantage 

 upon naming a truth from among these four assertions, 

 what would guide your choice ? There is certainly a 

 little difference in the impressions of assent with which 

 we regard the four; but whether it be of any real 

 strength, we may test in this way : Supposing the 

 benefit in question to be 1000/., would you not let 

 another person choose for you, almost at his pleasure, 

 and certainly for a shilling ? 



On this we remark, firstly, that by it we feel sensible 

 of our assent and dissent to propositions derived in very 

 different ways, being a sort of impression which is of 

 the same kind in all. To make this clearer, observe 

 the following: A merchant has freighted a ship, which 

 he expects (is not certain) will arrive at her port. Now 

 suppose a lottery, in which it is quite certain that every 

 ticket is marked with a letter, and that all the letters 

 enter in equal numbers. If I ask him, which is most 

 probable, that his ship will come into port, or that he 

 will draw no letter if he draw, he will answer, unques- 

 tionably, the first, for the second will certainly not hap- 



