I. The course of the subject next leads to an inquiry into the obligation of promises.[25] Where the first object, that presents itself, is the opinion of Franciscus Connanus, a man of no ordinary learning. He maintains an opinion that the law of nature and of nations does not enforce the fulfilment of those agreements, which do not include an express contract.[26] Yet the fulfilment of them is right, in cases, where, even without a promise, the performance would be consonant to virtue and equity. In support of his opinion, he brings not only the sayings of Lawyers, but likewise the following reasons. He says, that the person, who makes, and he who believes, a rash promise, are equally to blame. For the fortunes of all men would be in imminent danger, if they were bound by such promises, which often proceed from motives of vanity rather than from a settled deliberation, and are the result of a light and inconsiderate mind. Lastly, the performance of whatever is any way just in itself, ought to be left to the free will of every one, and not exacted according to the rigid rules of necessity. He says that it is shameful not to fulfil promises; not because it is unjust, but because it argues a levity in making them. In support of his opinion, he appeals also to the testimony of Tully, who has said, that those promises are not to be kept, which are prejudicial to the person to whom they are made, nor, if they are more detrimental to the giver than beneficial to the receiver. But if the performance of an engagement is begun upon the strength of a promise, but not finished, he does not require a complete fulfilment of the promise, but only some compensation to the party for the disappointment. Agreements, he continues, have no intrinsic force of obligation, but only what they derive from the express contracts, in which they are included, or to which they are annexed, or from the delivery of the thing promised. From whence arise actions, on the one side, and exceptions on the other, and bars to all claims of recovery. But it is through favour of the laws alone, which give the efficacy of obligation to what is only fair and equitable in itself, that obligatory agreements, such as express covenants and other things of that kind, derive their force.