members of the society. This immediately causes that interest to operate upon them; and interest is the first obligation to the performance of promises.
Afterwards a sentiment of morals concurs with interest, and becomes a new obligation upon mankind. This sentiment of morality, in the performance of promises, arises from the same principles as that in the abstinence from the property of others. Public interest, education, and the artifices of politicians, have the same effect in both cases. The difficulties, that occur to us, in supposing a moral obligation to attend promises, we either surmount or elude. For instance; the expression of a resolution is not commonly suppos'd to be obligatory; and we cannot readily conceive how the making use of a certain form of words shou'd be able to cause any material difference. Here, therefore, we feign a new act of the mind, which we call the willing an obligation; and on this we suppose the morality to depend. But we have prov'd already, that there is no such act of the mind, and consequently that promises impose no natural obligation.
To confirm this, we may subjoin some other reflections concerning that will, which is suppos'd to enter into a promise, and to cause its obligation. 'Tis evident, that the will alone is never suppos'd to cause the obligation, but must be express'd by words or signs, in order to impose a tye upon any man. The expression being once brought in as subservient to the will, soon becomes the principal part of the promise; nor will a man be less bound by his word, tho' he secretly give a different direction to his intention, and with-hold himself both from a resolution, and from willing an obligation. But tho' the expression makes on most occasions the whole of the promise, yet it does not always so; and one, who shou'd make use of any expression, of which he knows not the meaning, and which he uses without any intention of binding himsel£ wou'd not certainly be bound by it. Nay, tho' he knows its meaning, yet if he uses it in jest only, and
