The different accounts which have been given of the nature of virtue, or of the temper of mind which constitutes the excellent and praise-worthy character, may be reduced to three different classes. According to some, the virtuous temper of mind does not consist in any one species of affections, but in the proper government and direction of all our affections, which may be either virtuous or vicious according to the objects which they pursue, and the degree of vehemence with which they pursue them. According to these authors, therefore, virtue consists in propriety.
According to others, virtue consists in the judicious pursuit of our own private interest and happiness, or in the proper government and direction of those selfish affections which aim solely at this end. In the opinion of these authors, therefore, virtue consists in prudence.
Another set of authors make virtue consist in those affections only which aim at the happiness of others, not in those which aim at our own. According to them, therefore, disinterested benevolence is the only motive which can stamp upon any action the character of virtue.
The character of virtue, it is evident, must either be ascribed indifferently to all our affections, when under proper government and direction; or it must be confined to some one class or division of them. The great division of our affections is into the selfish and the benevolent. If the character of virtue, therefore, cannot be ascribed indifferently to all our affections, when under proper government and direction, it must be confined either to those which aim directly at our own private happiness, or to those which aim directly at that of others. If virtue, therefore, does not consist in propriety, it must consist either in prudence or in benevolence. Besides these three, it is scarce possible to imagine that any other account can be given of the nature of virtue. I shall endeavour to show hereafter how all the other accounts, which are seemingly different from any of these, coincide at bottom with some one or other of them.