There is another phaenomenon, which is parallel to this, viz, that acquaintance, without any kind of relation, gives rise to love and kindness.  When we have contracted a habitude and intimacy with any person; though in frequenting his company we have not been able to discover any very valuable quality, of which he is possessed; yet we cannot forebear preferring him to strangers, of whose superior merit we are fully convinced.  These two phaenomena of the effects of relation and acquaintance will give mutual light to each other, and may be both explained from the same principle.

Those, who take a pleasure in declaiming against human nature, have observed, that man is altogether insufficient to support himself; and that when you loosen all the holds, which he has of external objects, he immediately drops down into the deepest melancholy and despair.  From this, say they, proceeds that continual search after amusement in gaming, in hunting, in business; by which we endeavour to forget ourselves, and excite our spirits from the languid state, into which they fall, when not sustained by some brisk and lively emotion.  To this method of thinking I so far agree, that I own the mind to be insufficient, of itself, to its own entertainment, and that it naturally seeks after foreign objects, which may produce a lively sensation, and agitate the spirits.  On the appearance of such an object it awakes, as it were, from a dream:  The blood flows with a new tide:  The heart is elevated:  And the whole man acquires a vigour, which he cannot command in his solitary and calm moments.  Hence company is naturally so rejoicing, as presenting the liveliest of all objects, viz, a rational and thinking Being like ourselves, who communicates to us all the actions of his mind; makes us privy to his inmost sentiments and affections; and lets us see, in the very instant of their production, all the emotions, which are caused by any object.  Every lively idea is agreeable, but especially that of a passion, because such an idea becomes a kind of passion, and gives a more sensible agitation to the mind, than any other image or conception.

This being once admitted, all the rest is easy.  For as the company of strangers is agreeable to us for a short time, by inlivening our thought; so the company of our relations and acquaintance must be peculiarly agreeable, because it has this effect in a greater degree, and is of more durable influence.  Whatever is related to us is conceived in a lively manner by the easy transition from ourselves to the related object.  Custom also, or acquaintance facilitates the entrance, and strengthens the conception of any object.  The first case is parallel to our reasonings from cause and effect; the second to education.  And as reasoning and education concur only in producing a lively and strong idea of any object; so is this the only particular, which is common to relation and acquaintance.  This must, therefore, be the influencing quality, by which they produce all their common effects; and love or kindness being one of these effects, it must be from the force and liveliness of conception, that the passion is derived.  Such a conception is peculiarly agreeable, and makes us have an affectionate regard for every thing, that produces it, when the proper object of kindness and goodwill.