In order to a distinct apprehension of the present subject, it must be premised, that an agreeable object produceth always a pleasant emotion, and a disagreeable object one that is painful. This is a general law of nature, which admits not a single exception. Agreeableness in the object or cause is indeed so essentially connected with pleasure in the emotion its effect, that an agreeable object cannot be better defined, than by its power of producing a pleasant emotion. Disagreeableness in the object or cause, has the same necessary connection with pain in the emotion produced by it. From this preliminary it appears, that to inquire for what end an emotion is made pleasant or painful, resolves into an inquiry for what end its cause is made agreeable or disagreeable. And from the most accurate induction it will be discovered, that no cause of an emotion is made agreeable or disagreeable arbitrarily; but that these qualities are so distributed as to answer wise and good purposes. It is an invincible proof of the benignity of the Deity, that we are surrounded with things generally agreeable, which contribute remarkably to our entertainment and to our happiness. Some things are made disagreeable, such as a rotten carcass, because they are noxious. Others, a dirty marsh, for example, or a barren heath, are made disagreeable in order to excite our industry. And with respect to the few things that are neither agreeable nor disagreeable; it will be made evident, that their being left indifferent is not a work of chance but of wisdom. Of such I shall have occasion to give several instances. Having attempted to assign the final causes of emotions and passions considered as pleasant or painful, we proceed to the final causes of the desires involved in them. This seems a work of some difficulty; for the desires that accompany different passions have very different aims, and seldom or never demand precisely the same gratification. One passion moves us to cling to its object, one to fly from it; one passion impels to action for our own good, and one for the good of others; one passion prompts us to do good to ourselves or others, and one to do mischief, frequently to others, and sometimes even to ourselves. Deliberating upon this intricate subject, and finding an intimate correspondence betwixt our desires and their objects, it is natural to think that the former must be regulated in some measure by the latter. In this view, I begin with desire directed upon an inanimate object.