The emotions produced as above may properly be termed _secondary_, being occasioned either by antecedent emotions or antecedent passions, which in this respect may be termed _primary_. And to complete the present theory, I must now remark a difference betwixt a primary emotion and a primary passion in the production of secondary emotions. A secondary emotion cannot but be more faint than the primary; and therefore, if the chief or principal object have not the power to raise a passion, the accessory object will have still less power. But if a passion be raised by the principal object, the secondary emotion may readily swell into a passion for the accessory, provided the accessory be a proper object for desire. And thus it happens that one passion is often productive of another. Examples are without number: the sole difficulty is a proper choice. I begin with self-love, and the power it hath to generate other passions. The love which parents bear their children, is an illustrious example of the foregoing doctrine. Every man, beside making part of a greater system, like a comet, a planet, or satellite only; hath a less system of his own, in the centre of which he represents the sun dispersing his fire and heat all around. The connection between a man and his children, fundamentally that of cause and effect, becomes, by the addition of other circumstances, the completest that can be among individuals; and therefore, self-love, the most vigorous of all passions, is readily expanded upon children. The secondary emotion they at first produce by means of their connection, is, generally speaking, sufficiently strong to move desire even from the beginning; and the new passion swells by degrees, till it rival in some measure self-love, the primary passion. The following case will demonstrate the truth of this theory. Remorse for betraying a friend, or murdering an enemy in cold blood, makes a man even hate himself. In this state, it is a matter of experience, that he is scarce conscious of any affection to his children, but rather of disgust or ill-will. What cause can be assigned for this change, other than the hatred which beginning at himself, is expanded upon his children? And if so, may we not with equal reason derive from self-love the affection a man for ordinary has to them? The affection a man bears to his blood-relations, depends on the same principle. Self-love is also expanded upon them; and the communicated passion, is more or less vigorous in proportion to the connection. Nor doth self-love rest here: it is, by the force of connection, communicated even to things inanimate. And hence the affection a man bears to his property, and to every thing he calls his own.