In an influential article, Frankfurt (1971) argued that the difference between persons and other agents consists in the structure of their will. Only persons reflect on and care about their motivations. According to Frankfurt, this reflective evaluation of our motives usually results in the formation of second-order desires: desires that are directed at first-order desires (which are directed at goals and actions). When a person wants to have a certain desire and wants to be moved by it, then he or she is said to “identify” with the desire and its motivational efficacy. On this hierarchical account of agency, the role of higher-order attitudes is essential to the kind of agency that distinguishes persons from other agents. Taylor (1977) took this as a starting point for an account of distinctively human agency, under the assumption that the distinction between persons and non-persons is, essentially, the distinction between human and non-human agents. It is not entirely clear whether Frankfurt and Taylor meant to provide an alternative to the standard theory of agency or an extension of it.[8] On one reading, they accepted the account of intentional agency provided by the standard theory, and they proposed a hierarchical extension of the standard theory that captures the kind of agency that is distinctive of persons or human agents. (For an influential critique of such hierarchical accounts see Watson 1975.)