'Tis reasonable for those philosophers who assert justice to be a natural virtue, and antecedent to human conventions, to resolve all civil allegiance into the obligation of a promise, and assert that 'tis our own consent alone which binds us to any submission to magistracy. For as all government is plainly an invention of men, and the origin of most governments is known in history, 'tis necessary to mount higher, in order to find the source of our political duties, if we would assert them to have any _natural_ obligation of morality. These philosophers, therefore, quickly observe, that society is as ancient as the human species, and those three fundamental laws of nature as ancient as society; so that, taking advantage of the antiquity and obscure origin of these laws, they first deny them to be artificial and voluntary inventions of men, and then seek to ingraft on them those other duties which are more plainly artificial. But being once undeceived in this particular, and having found that _natural_ as well as _civil_ justice derives its origin from human conventions, we shall quickly perceive how fruitless it is to resolve the one into the other, and seek, in the laws of nature, a stronger foundation for our political duties than interest and human conventions; while these laws themselves are built on the very same foundation. On whichever side we turn this subject, we shall find that these two kinds of duty are exactly on the same footing, and have the same source both of their _first invention_ and _moral obligation_. They are contrived to remedy like inconveniences, and acquire their moral sanction in the same manner, from their remedying those inconveniences. These are two points which we shall endeavour to prove as distinctly as possible.