A man, who from any motives has entertained a resolution of performing an action, naturally runs into every other view or motive, which may fortify that resolution, and give it authority and influence on the mind.

To confirm us in any design, we search for motives drawn from interest, from honour, from duty.

What wonder, then, that pity and benevolence, malice, and anger, being the same desires arising from different principles, should so totally mix together as to be undistinguishable?
As to the connexion betwixt benevolence and love, anger and hatred, being original and primary, it admits of no difficulty.
We may add to this another experiment, viz, that benevolence and anger, and consequently love and hatred, arise when our happiness or misery have any dependance on the happiness or misery of another person, without any farther relation.

I doubt not but this experiment will appear so singular as to excuse us for stopping a moment to consider it.
Suppose, that two persons of the same trade should seek employment in a town, that is not able to maintain both, it is plain the success of one is perfectly incompatible with that of the other, and that whatever is for the interest of either is contrary to that of his rival, and so vice versa.

Suppose again, that two merchants, though living in different parts of the world, should enter into co-partnership together, the advantage or loss of one becomes immediately the advantage or loss of his partner, and the same fortune necessarily attends both.