Let us apply these remarks upon the nature of promises to the doctrine of a social contract. It is not through the medium of any supposed promise or engagement that we are induced to believe that the conduct of our neighbour will not be ridiculously inconsistent or wantonly malicious. If he protest in the most solemn way against being concluded by any such promise, at the same time that he conducts himself in a rational and sober manner, he will not find us less disposed to confide in him. We depend as readily upon a foreigner that he will not break the laws, and expose himself to their penalties (for this has been supposed to be one of the principal branches of the social contract), as we do upon our countryman. If we do not depend equally upon the Arabs who inhabit the plains of Asia, it is not because we impute to them a deficiency in their social contract, but because we are ignorant of their principles of conduct, or know that those principles do not afford us a sufficient security as to the particulars of our intercourse with them. Tell a man what will be the solid and substantial effects of his proceeding, how it will affect his neighbours, and what influence it will have upon his own happiness, and you speak to the unalienable feelings of the human mind. But tell him that, putting these things for the present out of our consideration, it is sufficient that he has promised a certain conduct, or that, if he have not expressly promised it, he has promised it by implication, or that, if he have not promised it, his ancestors a few generations back promised it for him; and you speak of a motive that scarcely finds a sympathetic chord in one human breast, and that few will so much as understand.
Few things can be more absurd than to talk of our having promised obedience to the laws. If the laws depend upon promises for their execution, why are they accompanied with sanctions? Why is it considered as the great arcanum of legislation to make laws that are easy of execution, and that need no assistance from the execrable intervention of oaths and informers?