I shall add, as a corollary to this reasoning, that since no action can be laudable or blameable, without some motives or impelling passions, distinct from the sense of morals, these distinct passions must have a great influence on that sense.  It is according to their general force in human nature, that we blame or praise.  In judging of the beauty of animal bodies, we always carry in our eye the oeconomy of a certain species; and where the limbs and features observe that proportion, which is common to the species, we pronounce them handsome and beautiful.  In like manner we always consider the natural and usual force of the passions, when we determine concerning vice and virtue; and if the passions depart very much from the common measures on either side, they are always disapproved as vicious.  A man naturally loves his children better than his nephews, his nephews better than his cousins, his cousins better than strangers, where every thing else is equal.  Hence arise our common measures of duty, in preferring the one to the other.  Our sense of duty always follows the common and natural course of our passions.

To avoid giving offence, I must here observe, that when I deny justice to be a natural virtue, I make use of the word, natural, only as opposed to artificial.  In another sense of the word; as no principle of the human mind is more natural than a sense of virtue; so no virtue is more natural than justice.  Mankind is an inventive species; and where an invention is obvious and absolutely necessary, it may as properly be said to be natural as any thing that proceeds immediately from original principles, without the intervention of thought or reflection.  Though the rules of justice be artificial, they are not arbitrary.  Nor is the expression improper to call them Laws of Nature; if by natural we understand what is common to any species, or even if we confine it to mean what is inseparable from the species.

SECT.  II OF THE ORIGIN OF JUSTICE AND PROPERTY

We now proceed to examine two questions, viz, concerning the manner, in which the rules of justice are ESTABLISHed by the artifice of men; and concerning the reasons, which determine us to attribute to the observance or neglect of these rules A moral beauty and deformity.  These questions will appear afterwards to be distinct.  We shall begin with the former.