 It is important to distinguish methodological issues in economics (see Hausman 2008) from normative questions. However, they are often intertwined in intricate  ways.[11]  One example concerns assumptions about human rationality: standard economic models assume perfect rationality, which excludes problems such as weakness of the will, so that normative criticisms of markets that build on the ability of more rational market participants to exploit the weaknesses of less rational market participants cannot be raised within this framework. More generally, plausible arguments challenge the possibility of value-free economic theorizing (see e.g., Mongin 2006). This means that philosophers who want to discuss normative issues about markets need to take care to make explicit the normative assumptions that might enter their view of these markets because they are built into the economists’ models. While the mainstream of economic theorizing in the last decades has used a rational choice methodology, new approaches, for example, behavioral economics or institutional economics, have worked with different assumptions, raising new methodological challenges. For example, explorations of the importance of norms of fairness in economic contexts (e.g., Kahneman/Knetsch/Thaler 1986; Fehr/Schmidt 1999) raise questions about the relation between the fairness norms favored by political philosophers and the norms observable in people’s behavior. Another interesting area are “nudges” that are supposed to lead people to more rational or more socially desirable behavior by changing institutional defaults (e.g., Thaler/Sunstein 2008), which leads to philosophical questions about paternalism.