Now desire is wholly inseparable from preference, or a perception of the excellence, real or supposed, of any object. I say real or supposed, for aIl object totally destitute of real and intrinsic excellence may become an object of desire on account of the imaginary excellence that is ascribed to it. Nor is this the only mistake to which human intellect is liable. We may desire an object of absolute excellence, not for its real and genuine recommendations, but for some fictitious attractions we may impute to it. This is always in some degree the case when a beneficial action is performed from an ill motive.
Nothing seems more inconsistent with our ideas of virtue.
A virtuous preference is the preference of an object for the sake of certain qualities which really be long to it. To attribute virtue to any other species of preference would be nearly the same as to suppose that an accidental effect of my conduct, which was out of my view at the time of adopting it, might entitle me to the appellation of virtuous. It must begin with a collective idea of the human species. It must discriminate, among the different causes that produce a pleasurable state of mind, that which produces the most exquisite and durable pleasure. Eminent virtue requires that I should have a grand view of the tendency of knowledge to produce happiness, and of just political institution to favour the progress of knowledge.