What alone will beget a doubt concerning the theory, on which I insist, is the influence of education and acquired habits, by which we are so accustomed to blame injustice, that we are not, in every instance, conscious of any immediate reflection on the pernicious consequences of it. The views the most familiar to us are apt, for that very reason, to escape us; and what we have very frequently performed from certain motives, we are apt likewise to continue mechanically, without recalling, on every occasion, the reflections, which first determined us. The convenience, or rather necessity, which leads to justice is so universal, and everywhere points so much to the same rules, that the habit takes place in all societies; and it is not without some scrutiny, that we are able to ascertain its true origin. The matter, however, is not so obscure, but that even in common life we have every moment recourse to the principle of public utility, and ask, WHAT MUST BECOME OF THE WORLD, IF SUCH PRACTICES PREVAIL? HOW COULD SOCIETY SUBSIST UNDER SUCH DISORDERS? Were the distinction or separation of possessions entirely useless, can any one conceive, that it ever should have obtained in society? Thus we seem, upon the whole, to have attained a knowledge of the force of that principle here insisted on, and can determine what degree of esteem or moral approbation may result from reflections on public interest and utility. The necessity of justice to the support of society is the sole foundation of that virtue; and since no moral excellence is more highly esteemed, we may conclude that this circumstance of usefulness has, in general, the strongest energy, and most entire command over our sentiments. It must, therefore, be the source of a considerable part of the merit ascribed to humanity, benevolence, friendship, public spirit, and other social virtues of that stamp; as it is the sole source of the moral approbation paid to fidelity, justice, veracity, integrity, and those other estimable and useful qualities and principles. It is entirely agreeable to the rules of philosophy, and even of common reason; where any principle has been found to have a great force and energy in one instance, to ascribe to it a like energy in all similar instances. This indeed is Newton's chief rule of philosophizing [Footnote: Principia. Lib. iii.]. SECTION IV. OF POLITICAL SOCIETY.