When any affection is infused by sympathy, it is at first known only by its effects, and by those external signs in the countenance and conversation, which convey an idea of it. This idea is presently converted into an impression, and acquires such a degree of force and vivacity, as to become the very passion itself, and produce an equal emotion, as any original affection. However instantaneous this change of the idea into an impression may be, it proceeds from certain views and reflections, which will not escape the strict scrutiny of a philosopher, though they may the person himself, who makes them.
It is evident, that the idea, or rather impression of ourselves is always intimately present with us, and that our consciousness gives us so lively a conception of our own person, that it is not possible to imagine, that anything can in this particular go beyond it. Whatever object, therefore, is related to ourselves must be conceived with a little vivacity of conception, according to the foregoing principles; and though this relation should not be so strong as that of causation, it must still have a considerable influence. Resemblance and contiguity are relations not to be neglected; especially when by an inference from cause and effect, and by the observation of external signs, we are informed of the real existence of the object, which is resembling or contiguous.
Now it is obvious, that nature has preserved a great resemblance among all human creatures, and that we never remark any passion or principle in others, of which, in some degree or other, we may not find a parallel in ourselves. The case is the same with the fabric of the mind, as with that of the body. 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 afterwards.59 All these relations, when united together, convey the impression or consciousness of our own person to the idea of the sentiments or passions of others, and makes us conceive them in the strongest and most lively manner.
It has been remarked in the beginning of this treatise, that all ideas are borrowed from impressions, and that these two kinds of perceptions differ only in the degrees of force and vivacity, with which they strike upon the soul. The component part of ideas and impressions are precisely alike. The manner and order of their appearance may be the same. The different degrees of their force and vivacity are, therefore, the only particulars, that distinguish them: And as this difference may be removed, in some measure, by a relation betwixt the impressions and ideas, it is no wonder an idea of a sentiment or passion, may by this means be enlivened as to become the very sentiment or passion. The lively idea of any object always approaches is impression; and it is certain we may feel sickness and pain from the mere force of imagination, and make a malady real by often thinking of it. But this is most remarkable in the opinions and affections; and it is there principally that a lively idea is converted into an impression. Our affections depend more upon ourselves, and the internal operations of the mind, than any other impressions; for which reason they arise more naturally from the imagination, and from every lively idea we form of them. This is the nature and cause of sympathy; and it is after this manner we enter so deep into the opinions and affections of others, whenever we discover them.
What is principally remarkable in this whole affair is the strong confirmation these phenomena give to the foregoing system concerning the understanding, and consequently to the present one concerning the passions; since these are analogous to each other. It is indeed evident, that when we sympathize with the passions and sentiments of others, these movements appear
