SECT. 9.] Measurement of Belief. 127 



torted by our state of feeling at the time, dimmed by the 

 degree of our recollection of them afterwards, and probably 

 received from time to time with varying force according to 

 the way in which they happen to combine in our conscious 

 ness at the moment. To borrow a striking illustration from 

 Abraham Tucker, the substructure of our convictions is not 

 so much to be compared to the solid foundations of an ordi 

 nary building, as to the piles of the houses of Rotterdam 

 which rest somehow in a deep bed of soft mud. They bear 

 their weight securely enough, but it would not be easy to 

 point out accurately the dependence of the different parts 

 upon one another. Directly we begin to think of the amount 

 of our belief, we have to think of the arguments by which it 

 is produced in fact, these arguments will intrude themselves 

 without our choice. As each in turn flashes through the 

 mind, it modifies the strength of our conviction ; we are like 

 a person listening to the confused hubbub of a crowd, where 

 there is always something arbitrary in the particular sound 

 we choose to listen to. There may be reasons enough to 

 suffice abundantly for our ultimate choice, but on examina 

 tion we shall find that they are by no means apprehended 

 with the same force at different times. The belief produced 

 by some strong argument may be very decisive at the mo 

 ment, but it will often begin to diminish when the argument 

 is not actually before the mind. It is like being dazzled by 

 a strong light ; the impression still remains, but begins al 

 most immediately to fade away. I think that this is the 

 case, however we try to limit the sources of our conviction. 



9. (II) But supposing that it were possible to strike 

 a sort of average of this fluctuating state, should we find this 

 average to be of the amount assigned by theory ? In other 

 words, is our natural belief in the happening of two different 

 events in direct proportion to the frequency with which those 



