The moral duties which fell under the consideration of the casuists were chiefly those which can, in some measure at least, be circumscribed within general rules, and of which the violation is naturally attended with some degree of remorse and some dread of suffering punishment. The design of that institution which gave occasion to their works, was to appease those terrors of conscience which attend upon the infringement of such duties. But it is not every virtue of which the defect is accompanied with any very severe compunctions of this kind, and no man applies to his confessor for absolution, because he did not perform the most generous, the most friendly, or the most magnanimous action which, in his circumstances, it was possible to perform. In failures of this kind, the rule that is violated is commonly not very determinate, and is generally of such a nature too, that though the observance of it might entitle to honour and reward, the violation seems to expose to no positive blame, censure, or punishment. The exercise of such virtues the casuists seem to have regarded as a sort of works of supererogation, which could not be very strictly enacted, and which it was therefore unnecessary for them to treat of. The breaches of moral duty, therefore, which came before the tribunal of the confessor, and upon that account fell under the cognizance of the casuists, were chiefly of three different kinds. First and principally, breaches of the rules of justice. The rules here are all express and positive, and the violation of them is naturally attended with the consciousness of deserving, and the dread of suffering punishment both from God and man. Secondly, breaches of the rules of chastity. These in all grosser instances are real breaches of the rules of justice, and no person can be guilty of them without doing the most unpardonable injury to some other. In smaller instances, when they amount only to a violation of those exact decorums which ought to be observed in the conversation of the two sexes, they cannot indeed justly be considered as violations of the rules of justice. They are generally, however, violations of a pretty plain rule, and, at least in one of the sexes, tend to bring ignominy upon the person who has been guilty of them, and consequently to be attended in the scrupulous with some degree of shame and contrition of mind.