However the parts may differ in shape or size, their structure and composition are in general the same.

There is a very remarkable resemblance, which preserves itself amidst all their variety; and this resemblance must very much contribute to make us enter into the sentiments of others; and embrace them with facility and pleasure.
Accordingly we find, that where, beside the general resemblance of our natures, there is any peculiar similarity in our manners, or character, or country, or language, it facilitates the sympathy.

The stronger the relation is betwixt ourselves and any object, the more easily does the imagination make the transition, and convey to the related idea the vivacity of conception, with which we always form the idea of our own person.
Nor is resemblance the only relation, which has this effect, but receives new force from other relations, that may accompany it.

The sentiments of others have little influence, when far removed from us, and require the relation of contiguity, to make them communicate themselves entirely.

The relations of blood, being a species of causation, may sometimes contribute to the same effect; as also acquaintance, which operates in the same manner with education and custom; as we shall see more fully [Part II.Sect.