T 3.2.5.7

If any one dissent from this, he must give a regular proof of these two propositions, viz. that there is a peculiar act of the mind, annext to promises; and that consequent to this act of the mind, there arises an inclination to perform, distinct from a sense of duty. I presume, that it is impossible to prove either of these two points; and therefore I venture to conclude, that promises are human inventions, founded on the necessities and interests of society.