Having explained the nature of an emotion and mentioned several causes by which it is produced, we proceed to an observation of considerable importance in the science of human nature, that some emotions are accompanied with desire, and that others, after a short existence, pass away without producing desire of any sort. The emotion raised by a fine landscape or a magnificent building, vanisheth generally without attaching our hearts to the object; which also happens with relation to a number of fine faces in a crowded assembly. But the bulk of emotions are accompanied with desire of one sort or other, provided only a fit object for desire be suggested. This is remarkably the case of emotions raised by human actions and qualities. A virtuous action raiseth in every spectator a pleasant emotion, which is generally attended with a desire to do good to the author of the action. A vicious action, on the other hand, produceth a painful emotion; and of consequence a desire to have the author punished. Even things inanimate often raise desire. The goods of fortune are objects of desire almost universally; and the desire, when more than commonly vigorous, obtains the name of _avarice_. The pleasant emotion produced in a spectator by a capital picture in the possession of a prince, seldom raiseth desire. But if such a picture be exposed to sale, desire of having or possessing is the natural consequence of the emotion. If now an emotion be sometimes productive of desire, somtimes not, it comes to be a material inquiry, in what respect a passion differs from an emotion. Is passion in its nature or feeling distinguishable from emotion? I have been apt to think that there must be a distinction, when the emotion seems in all cases to precede the passion, and to be the cause or occasion of it. But after the strictest examination, I cannot perceive any such distinction betwixt emotion and passion. What is love to a mistress, for example, but a pleasant emotion raised by a sight or idea of the person beloved, joined with desire of enjoyment? In what else consists the passion of resentment, but in a painful emotion occasioned by the injury, accompanied with desire to chastise the author of the injury? In general, as to every sort of passion, we find no more in the composition, but the particulars now mentioned, an emotion pleasant or painful accompanied with desire. What then shall we say upon this subject? Are _passion_ and _emotion_ synonymous terms? This cannot be averred. No feeling nor agitation of the mind void of desire, is termed a passion; and we have discovered that there are many emotions which pass away without raising desire of any kind. How is the difficulty to be solved? There appears to me but one solution, which I relish the more, as it renders the doctrine of the passions and emotions simple and perspicuous. The solution follows. An internal motion or agitation of the mind, when it passeth away without raising