Preferences often change—even in short time intervals—due to either the mere passage of time (present-biased preferences) or changes in visceral or environmental conditions (state-dependent preferences). On the basis of empirical findings concerning state-dependent preferences, we critically discuss the “Aristotelian” view of unitary decision makers in economics. We illustrate that the conceptualization of preferences as “present-biased” as opposed to “state-dependent” has very different normative implications for which preferences should be considered “rational.” Empirically, however, the two concepts are very difficult to distinguish. The economist can justify any paternalistic intervention if she can conceptualize changing preferences so flexibly, and she can easily become a benevolent despot. We therefore urge for a more careful “Heraclitean” view of decision-making that accepts that a person may consist of multiple selves.

偏好经常会发生变化，即使是在很短的时间间隔内，由于仅仅是时间的流逝（当前偏向的偏好）或本能或环境条件的变化（依赖于状态的偏好）。基于有关国家依赖偏好的实证研究结果，我们批判性地讨论了经济学中单一决策者的“亚里士多德”观点。我们说明，将偏好概念化为“当前偏见”与“依赖国家”相对，具有非常不同的规范含义，因此偏好应被视为“理性”。然而，根据经验，这两个概念很难区分。如果经济学家能够如此灵活地概念化不断变化的偏好，那么她就可以证明任何家长式干预都是合理的，并且她很容易成为仁慈的暴君。