 In attempting to distinguish between natural and social obstacles we shall inevitably come across gray areas. An important example is that of obstacles created by impersonal economic forces. Do economic constraints like recession, poverty and unemployment merely incapacitate people, or do they also render them unfree? Libertarians and egalitarians have provided contrasting answers to this question by appealing to different conceptions of constraints. Thus, one way of answering the question is by taking an even more restrictive view of what counts as a constraint on freedom, so that only a subset of the set of obstacles brought about by other persons counts as a restriction of freedom: those brought about intentionally. In this case, impersonal economic forces, being brought about unintentionally, do not restrict people’s freedom, even though they undoubtedly make many people unable to do many things. This last view has been taken by a number of market-oriented libertarians, including, most famously, Friedrich von Hayek (1960, 1982), according to whom freedom is the absence of coercion, where to be coerced is to be subject to the arbitrary will of another. (Notice the somewhat surprising similarity between this conception of freedom and the republican conception discussed earlier, in section 3.2) Critics of libertarianism, on the other hand, typically endorse a broader conception of constraints on freedom that includes not only intentionally imposed obstacles but also unintended obstacles for which someone may nevertheless be held responsible (for Miller and Kristjánsson and Shnayderman this means morally responsible; for Oppenheim and Kramer it means causally responsible), or indeed obstacles created in any way whatsoever, so that unfreedom comes to be identical to inability (see Crocker 1980; Cohen 2011, pp. 193–97; Sen 1992; Van Parijs 1995; Garnett forthcoming).