The foregoing difference among the passions, is the work of nature. Experience brings on some variations. By all actions performed through the impulse of passion, desire is gratified, and the gratification is pleasant. This lesson we have from experience. And hence it is, that after an action has often been performed by the impulse merely of passion, the pleasure resulting from performance, considered beforehand, becomes a motive, which joins its force with the original impulse in determining us to act. Thus a child eats by the mere impulse of hunger: a young man thinks of the pleasure of gratification, which is a motive for him to eat: and a man farther advanced in life, hath the additional motive that it will contribute to his health. Instinctive passions are distinguished into two kinds. Where the cause is internal, they are denominated _appetites_: where external, they retain the common name of _passions_. Thus hunger, thirst, animal love, are termed _appetites_; while fear and anger, even when they operate blindly and by mere impulse, are termed _passions_. From the definition of a motive above given, it is easy to determine, with the greatest accuracy, what passions are selfish, what social. No passion can properly be termed selfish, but what prompts me to exert actions in order for my own good; nor social, but what prompts me to exert actions in order for the good of another. The motive is that which determines a passion to be social or selfish. Hence it follows, that our appetites, which make us act blindly and by mere impulse, cannot be reckoned either social or selfish; and as little the actions they produce. Thus eating, when prompted by an impulse merely of nature, is neither social nor selfish. But add a motive, That it will contribute to my pleasure or my health, and it becomes in a measure selfish. On the other hand, when affection moves me to exert actions to the end solely of advancing my friend’s happiness, without the slightest regard to my own gratification, such actions are justly denominated _social_; and so is the affection, that is their cause. If another motive be added, That gratifying the affection will contribute to my own happiness, the actions I perform become partly selfish. Animal love when exerted into action by natural impulse singly, is neither social nor selfish: when exerted with a view to gratification and in order to make me happy, it is selfish. When the motive of giving pleasure to its object is superadded, it is partly social, partly selfish. A just action when prompted by the love of justice solely, is neither social nor selfish. When I perform an act of justice with a view to the pleasure of gratification, the action is selfish. I pay my debt for my own sake, not with a view to benefit my creditor. But let me suppose the money has been advanced by a friend without interest, purely to oblige me. In this case, together with the inclination to do justice, there arises a motive