BOOK II PART III
It is evident that the very same event, which by
its certainty would produce grief or joy, gives
always rise to fear or hope, when only proba-
ble and uncertain. In order, therefore, to under-
stand the reason why this circumstance makes
such a considerable difference, we must reflect
on what I have already advanced in the preced-
ing book concerning the nature of probability.
Probability arises from an opposition of con-
trary chances or causes, by which the mind is
not allowed to fix on either side, but is inces-
santly tost from one to another, and at one mo-
ment is determined to consider an object as
existent, and at another moment as the con-
trary. The imagination or understanding, call
it which you please, fluctuates betwixt the op-
posite views; and though perhaps it may be of-
tener turned to the one side than the other, it