This chapter focuses on what G. A. Cohen is trying to accomplish, and why his argument is fallacious. Cohen has a diagnosis of why political philosophy goes wrong: why, in his view, political philosophers are too sanguine about markets and capitalism. Cohen thinks philosophers have constructed unambitious theories of justice because they mistakenly treat human nature as a constraint on justice. In particular, Cohen thinks philosophers mistakenly treat facts about what people are willing to as a constraint on what people ought to do. The only way to know whether capitalism is corrupting or ennobling is to do bona fide social-scientific research. Capitalism and socialism are simply ways of organizing the ownership of property. In capitalism, individuals may own the means of production. In socialism, they may not, the means of production are owned collectively.