It has been asserted by some, that justice arises from Human Conventions, and proceeds from the voluntary choice, consent, or combination of mankind. If by convention be here meant a promise (which is the most usual sense of the word) nothing can be more absurd than this position. The observance of promises is itself one of the most considerable parts of justice, and we are not surely bound to keep our word because we have given our word to keep it. But if by convention be meant a sense of common interest, which sense each man feels in his own breast, which he remarks in his fellows, and which carries him, in concurrence with others, into a general plan or system of actions, which tends to public utility; it must be owned, that, in this sense, justice arises from human conventions. For if it be allowed (what is, indeed, evident) that the particular consequences of a particular act of justice may be hurtful to the public as well as to individuals; it follows that every man, in embracing that virtue, must have an eye to the whole plan or system, and must expect the concurrence of his fellows in the same conduct and behaviour. Did all his views terminate in the consequences of each act of his own, his benevolence and humanity, as well as his self-love, might often prescribe to him measures of conduct very different from those which are agreeable to the strict rules of right and justice.
Thus, two men pull the oars of a boat by common convention for common interest, without any promise or contract; thus gold and silver are made the measures of exchange; thus speech and words and language are fixed by human convention and agreement. Whatever is advantageous to two or more persons, if all perform their part; but what loses all advantage if only one perform, can arise from no other principle There would otherwise be no motive for any one of them to enter into that scheme of conduct.
[Footnote: This theory concerning the origin of property, and consequently of justice, is, in the main, the same with that hinted at and adopted by Grotius, ’Hinc discimus, quae fuerit causa, ob quam a primaeva communione rerum primo mobilium, deinde et immobilinm discessum est: nimirum quod cum non contenti homines vesci sponte natis, antra habitare, corpore aut nudo agere, aut corticibus arborum ferarumve pellibus vestito, vitae genus exquisitius delegissent, industria opus fuit, quam singuli rebus singulls adhiberent. Quo minus autem fructus in