(3) The third argument of this kind I shall make use of may be explained thus.  If we consider the ordinary course of human actions, we shall find, that the mind restrains not itself by any general and universal rules; but acts on most occasions as it is determined by its present motives and inclination.  As each action is a particular individual event, it must proceed from particular principles, and from our immediate situation within ourselves, and with respect to the rest of the universe.  If on some occasions we extend our motives beyond those very circumstances, which gave rise to them, and form something like general rules for our conduct, it is easy to observe, that these rules are not perfectly inflexible, but allow of many exceptions.  Since, therefore, this is the ordinary course of human actions, we may conclude, that the laws of justice, being universal and perfectly inflexible, can never be derived from nature, nor be the immediate offspring of any natural motive or inclination.  No action can be either morally good or evil, unless there be some natural passion or motive to impel us to it, or deter us from it; and it is evident, that die morality must be susceptible of all the same variations, which are natural to the passion.  Here are two persons, who dispute for an estate; of whom one is rich, a fool, and a batchelor; the other poor, a man of sense, and has a numerous family:  The first is my enemy; the second my friend.  Whether I be actuated in this affair by a view to public or private interest, by friendship or enmity, I must be induced to do my utmost to procure the estate to the latter.  Nor would any consideration of the right and property of the persons be able to restrain me, were I actuated only by natural motives, without any combination or convention with others.  For as all property depends on morality; and as all morality depends on the ordinary course of our passions and actions; and as these again are only directed by particular motives; it is evident, such a partial conduct must be suitable to the strictest morality, and coued never be a violation of property.  Were men, therefore, to take the liberty of acting with regard to the laws of society, as they do in every other affair, they would conduct themselves, on most occasions, by particular judgments, and would take into consideration the characters and circumstances of the persons, as well as the general nature of the question.  But it is easy to observe, that this would produce an infinite confusion in human society, and that the avidity and partiality of men would quickly bring disorder into the world, if not restrained by some general and inflexible principles.  Twas, therefore, with a view to this inconvenience, that men have established those principles, and have agreed to restrain themselves by general rules, which are unchangeable by spite and favour, and by particular views of private or public interest.  These rules, then, are artificially invented for a certain purpose, and are contrary to the common principles of human nature, which accommodate themselves to circumstances, and have no stated invariable method of operation.