perform that
action, and in the latter, that he possibly or probably will perform it.
Nothing is more fluctuating and inconstant on many occasions, than the
will of man; nor is there any thing but strong motives, which can give
us an absolute certainty in pronouncing concerning any of his future
actions. When we see a person free from these motives, we suppose a
possibility either of his acting or forbearing; and though in general
we may conclude him to be determined by motives and causes, yet this
removes not the uncertainty of our judgment concerning these causes, nor
the influence of that uncertainty on the passions. Since therefore we
ascribe a power of performing an action to every one, who has no very
powerful motive to forbear it, and refuse it to such as have; it may
justly be concluded, that power has always a reference to its exercise,
either actual or probable, and that we consider a person as endowed with
any ability when we find from past experience, that it is probable, or
at least possible he may exert it. And indeed, as our passions always
regard the real existence of objects, and we always judge of this
reality from past instances; nothing can be more likely of itself,
without any farther reasoning, than that power consists in the
possibility or probability of any action, as discovered by experience
and the practice of the world.

Now it is evident, that wherever a person is in such a situadon with
regard to me, that there is no very powerful motive to deter him from
injuring me, and consequently it is uncertain whether he will injure me
or not, I must be uneasy in such a situation, and cannot consider the
possibility or probability of that injury without a sensible concern.
The passions are not only affected by such events as are certain and
infallible, but also in an inferior degree by such as are possible
and contingent. And though perhaps I never really feel any harm, and
discover by the event, that, philosophically speaking, the person never
had any power of harming me; since he did not exert any; this prevents
not my uneasiness from the preceding uncertainty. The agreeable passions
may here operate as well as the uneasy, and convey a pleasure when I
perceive a good to become either possible or probable by the possibility
or probability of another's bestowing it on me, upon the removal of any
strong motives, which might formerly have hindered him.

But we may farther observe, that this satisfacti