A quality of the soul is either (1) a passion or emotion, or (2) a power or faculty, or (3) a habit or trained faculty; and so virtue must be one of these three. By (1) a passion or emotion we mean appetite, anger, fear, confidence, envy, joy, love, hate, longing, emulation, pity, or generally that which is accompanied by pleasure or pain; (2) a power or faculty is that in respect of which we are said to be capable of being affected in any of these ways, as, for instance, that in respect of which we are able to be angered or pained or to pity; and (3) a habit or trained faculty is that in respect of which we are well or ill-regulated or disposed in the matter of our affections; as, for instance, in the matter of being angered, we are ill regulated if we are too violent or too slack, but if we are moderate in our anger we are well regulated. And so with the rest.