Contemporary debates about the philosophy of social justice face challenges that are particular to our times. Martha Nussbaum developed – based on the capabilities-based development theory of Indian economist Amartya Sen – a sophisticated answer to many of these challenges, which she outlines in her book Creating Capabilities (2011). What are these contemporary challenges, and how does Nussbaum attempt to meet those challenges?
Global justice. It is uncontroversial that resources and opportunities are unfairly distributed. Not only within countries or states, but also among states. Some states have more resources, or are better able to manage their resources, than others. What do richer states morally owe poorer states? On the one hand, the inequalities between states are arbitrary and not the result of a fair process, so fairness requires that these inequalities be compensated, particularly since these inequalities currently lead to dehumanizing conditions for many. On the other hand, really equal distribution of resources across states is as good as impossible to govern.
Imperialism. We’d like to think that the times when Western nations went around the world invading territories, claiming land and resources for themselves and imposing their laws, norms, religions, languages, culture and governance upon other peoples is long behind us. Likewise, we’d like to think that women and men enjoy equality in all spheres of life and that battles like that of the suffragettes is a thing of the past. But reality is uncomfortable in this respect. Feminists and anti-colonialists have often persuasively pointed out that even after decolonisation and the legal recognition of equality for man and women, male and Western norms are still culturally dominant, often in hidden and implicit ways. Feminist philosophers have argued that many moral and political philosophies in the history of philosophy implicitly assume male standards that don’t quite fit women’s experiences. Likewise, Western philosophies have been shown to implicitly assume a European or US American context, thereby discounting non-Western societies from the outset, but at the same time claiming universal applicability. Western philosophies thus are in danger of implicitly making imperialist claims without realizing it. In this light, postmodern concerns – like those put forward by Nietzsche – spring to mind: is it at all possible to formulate a moral or political theory that has universal application, or does such a theory always amount to imperialism, whereby the dominant group imposes its arbitrary morality on everyone? But if a theory of justice has no universal applicability, can it be said to be a theory of justice at all? After all, aren’t we all owed the same respect, in virtue of our humanity?
Justice to animals. Can justice apply to non-human animals, too? Few would argue that animals can make the same moral claims as humans, or that they should have the same rights. But equally few would claim they are not owed any moral respect at all. Presumably, truth lies somewhere in between. Animals are sentient, they can feel pain and pleasure, fear and joy. Many people would argue that animals should be protected from pointless cruelty. But which criteria apply here? A theory of justice that is not at all able to consider or apply to non-human animals is, these days, considered to have a serious handicap.
The Capability Approach
Martha Nussbaum can’t be said to lack ambition. She claims that her theory of social justice meets all three of the above challenges. She starts from the Aristotelian idea that the idea of justice ought to be based on the question: “What is each person able to do and to be?” If we are to judge any society on its basic justice or decency, that’s the question we should ask, according to Nussbaum. To further break this question down, she has formulated ten capabilities, which form the basis of her account of justice. These ten capabilities are:
- Bodily health (“including reproductive health”)
- Bodily integrity (including “opportunities for sexual satisfaction and for choice in matters of reproduction”)
- Senses, imagination, and thought (“being able to use the senses, to imagine, to think, and to reason”)
- Emotions (“being able to have attachments to things and people outside of ourselves”)
- Practical reason (“being able to form a conception of the good”)
- Affiliation (“being able to live with and toward others”)
- Other species (“being able to live with concern for and in relation to animals, plants, and the world of nature”)
- Play (“being able to laugh, to play, to enjoy recreational activities”)
- Control over one’s environment (“being able to participate effectively in political choices” and “being able to hold property and having property rights”) 
These ten capabilities constitute Nussbaum’s account of social justice. To understand how they work, however, a few further things must be said about these capabilities.
Firstly, these ten capabilities form the basis of justice. Justice should be understood in these terms; they are not mere symptoms of justice.
Secondly, these ten capabilities are universal. They apply to all humans and even to non-human animals, regardless of culture of context.
Thirdly, having these capabilities, does not mean that one also enacts them. This should be a matter of free choice, according to Nussbaum. She therefore distinguishes ‘functioning’ from ‘capabilities’, whereby functioning refers to doing what a capability enables one to do. For instance, I may have the capability to connect with other species – I am able to do so and no one is hindering me from doing so nor coercing me to do so – but whether I actually choose to do so is a different matter. The capability approach is therefore a distinctly liberal approach.
Fourthly, Nussbaum employs a threshold with regard to these capabilities. That means that in order for a person to live a life of dignity, and for a society to deserve the label ‘decent’ or ‘minimally just’, these ten capabilities must be enabled to a certain, minimal, degree. It is hardly intelligible that a person could exercise them to a maximum degree, since contingent circumstances necessarily limit them. Hence, justice does not require that people are unlimited in the exercise of these capabilities, but that they have them to a certain degree.
Fifthly, the ten capabilities relate to each other. If the conditions for reasonable bodily health and longevity aren’t met, for instance, we also won’t be capable of many other things. A society is therefore just only if for each citizen conditions are provided that practically enable all ten capabilities to threshold level. That also means that the lack of one capability can not be compensated with an excess in another capability. No amount of education can compensate for the lack of bodily health. All capabilities must be met to threshold level.
Does Nussbaum’s account meet the three contemporary challenges?
According to Nussbaum, societies that are unable to reach a minimum threshold level of these ten capabilities for their members ought to receive help from societies that do have the resources and institutions to provide these ten capabilities. This is, according to Nussbaum, a reasonable demand for global justice.
Although Nussbaum claims that her approach has universal applicability, she is sensitive to the dangers of imperialism. However, she has thought of this too. The capabilities are sufficiently generic, according to Nussbaum, to allow for significant differences in cultural interpretation. How or to which extent we choose to play, make decisions about our bodies or relate to the other species can be informed in various ways by our religion, culture, upbringing, ethical views, tastes or environment.
Finally, the ten capabilities can be employed to evaluate not only the level of justice towards humans, but also non-human animal species. Perhaps even robots!
Thanks for reading my introduction, but who can really explain it better than Martha Nussbaum herself? I really recommend watching this lecture. It is very clear and detailed and really brings home why Nussbaum thinks all of this is very, very important.
 Martha Nussbaum, Creating Capabilities; The Human Development Approach (Cambridge, MA: Belknap Press of Harvard Univerity Press, 2011) p. 18
 Nussbaum, Creating Capabilities, 2011 and Martha Nussbaum, Frontiers of Justice: Disability, Nationality, Species Membership (Cambridge, MA: Belknap Press of Harvard University Press, 2006)