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.