In characterizing the moral psychology of citizens as represented in political liberalism, Rawls articulates three kinds of desires that illuminate aspects of their moral sensibility as reasonable: object-dependent desires, principle-dependent desires, and conception-dependent desires (PL 81–86).

Object-dependent desires, on the one hand, are desires that “can be described without the use of any moral conceptions, or reasonable or rational principles” (PL 82). Such desires are potentially unlimited in number, ranging from desires for such mundane objects as food, drink, and pleasures of various kinds to more complex desires for objects or states of affairs arising out of social life, among which Rawls includes “desires for status, power and glory and for property and wealth” (PL 82). As Rawls’s list suggests, these desires might be complex, some of them perhaps even being instrumentally related to other such desires. But the motivational force of these desires does not arise from a principle and no principle intrinsic to the object of the desire guides how the agent will pursue its satisfaction.

Principle-dependent desires and conception-dependent desires, on the other hand, are those in which the force of the desire involves a principle that is possible and intelligible only by virtue of an agent’s nature as rational and reasonable. That principle is both intrinsic to the goal or aim of the desire and guides or regulates how the agent should act to satisfy the desire. Among principle dependent desires, Rawls subdivides the group according to whether the principle upon which the desire is dependent is one of rationality or one of reasonability. As examples of desires dependent upon principles of rationality, he includes the desire to take the most eficient course of action or the desire to realize the greatest good.