But speculative reasonings, which cost so much pains to philosophers, are often formed by the world naturally, and without reflection; as difficulties which seem unsurmountable in theory, are easily got over in practice. Those who have an interest in the fidelity of women, naturally disapprove of their infidelity, and all the approaches to it. Those who have no interest are carried along with the stream. Education takes possession of the ductile minds of the fair sex in their infancy. And when a general rule of this kind is once established, men are apt to extend it beyond those principles from which it first arose. Thus, bachelors, however debauched, cannot choose but be shocked with any instance of lewdness or impudence in woman. And though all these maxims have a plain reference to generation, yet women past child-bearing have no more privilege in this respect than those who are in the flower of their youth and beauty. Men have undoubtedly an implicit notion, that all those ideas of modesty and decency have a regard to generation; since they impose not the same laws, _with the same force_, on the male sex, where that reason takes not place. The exception is there obvious and extensive, and founded on a remarkable difference, which produces a clear separation and disjunction of ideas. But as the case is not the same with regard to the different ages of women, for this reason, though men know that these notions are founded on the public interest, yet the general rule carries us beyond the original principle, and makes us extend the notions of modesty over the whole sex, from their earliest infancy to their extremest old age and infirmity. Courage, which is the point of honour among men, derives its merit in a great measure from artifice, as well as the chastity of women; though it has also some foundation in nature, as we shall see afterwards. As to the obligations which the male sex lie under with regard to chastity, we may observe that, according to the general notions of the world, they bear nearly the same proportion to the obligations of women, as the obligations of the law of nations do to those of the law of nature. 'Tis contrary to the interest of civil society, that men should have an _entire_ liberty of indulging their appetites in venereal enjoyment; but as this interest is weaker than in the case of the female sex, the moral obligation arising from it must be proportionably weaker. And to prove this we need only appeal to the practice and sentiments of all nations and ages. PART III. OF THE OTHER VIRTUES AND VICES. SECTION I. OF THE ORIGIN OF THE NATURAL VIRTUES AND VICES. We come now to the examination of such virtues and vices as are entirely natural, and have no dependence on the artifice and contrivance of men. The examination of these will conclude this system of morals.