_Causes evolved of the emotions and passions._ SECT. I. _Difference betwixt emotion and passion.---- Causes that are the most common and the most extensive.---- Passion considered as productive of action._ These branches are so interwoven, as to make it necessary that they be handled together. It is a fact universally admitted, that no emotion nor passion ever starts up in the mind, without a known cause. If I love a person, it is for good qualities or good offices: if I have resentment against a man, it must be for some injury he has done me; and I cannot pity any one, who is under no distress of body or of mind. The circumstances now mentioned, if they cause or occasion a passion, cannot be entirely indifferent: if they were, they could not move us in any degree. And we find upon examination, that they are not indifferent. Looking back upon the foregoing examples, the good qualities or good offices that attract my love, are antecedently agreeable. If an injury were not disagreeable, it would not occasion any resentment against the author; nor would the passion of pity be raised by an object in distress, if that object did not give us pain. These feelings antecedent to passion, and which seem to be the causes of passion, shall be distinguished by the name of _emotions_. What is now said about the production of passion, resolves into a very simple proposition, That we love what is pleasant, and hate what is painful. And indeed it is evident, that without antecedent emotions we could not have any passions; for a thing must be pleasant or painful, before it can be the object either of love or of hatred. As it appears from this short sketch, that passions are generated by means of prior emotions, it will be necessary to take first under consideration emotions and their causes. Such is the constitution of our nature, that upon perceiving certain external objects, we are instantaneously conscious of pleasure or pain. A flowing river, a smooth extended plain, a spreading oak, a towering hill, are objects of sight that raise pleasant emotions. A barren heath, a dirty marsh, a rotten carcass, raise painful emotions. Of the emotions thus produced, we inquire for no other cause but merely the presence of the object. It must further be observed, that the things now mentioned, raise emotions by means of their properties and qualities. To the emotion raised by a large river, its size, its force, and its fluency, contribute each a share. The pleasures of regularity, propriety, convenience, compose the emotion raised by a fine building.