Our love and hatred are always directed to some sensible being external to us; and when we talk of self-love, it is not in a proper sense, nor has the sensation it produces any thing in common with that tender emotion which is excited by a friend or mistress.

It is the same case with hatred.

We may be mortified by our own faults and follies; but never feel any anger or hatred except from the injuries of others.
But though the object of love and hatred be always some other person, it is plain that the object is not, properly speaking, the cause of these passions, or alone sufficient to excite them.

For since love and hatred are directly contrary in their sensation, and have the same object in common, if that object were also their cause, it would produce these opposite passions in an equal degree; and as they must, from the very first moment, destroy each other, none of them would ever be able to make its appearance.

There must, therefore, be some cause different from the object.
If we consider the causes of love and hatred, we shall find they are very much diversifyed, and have not many things in common.