T 2.2.4.5

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 conceiv'd 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 deriv'd. 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 good-will.