Chapter 3 formulated the philosopher’s role in terms of shared citizenship. Chapters 4–6 develop a global version of this view, according to which the philosopher is a theory-providing global discussant. Some view about the impact of ideas at the global level must be in place for there to be reflection on anything like a genuinely global philosophy or to make good on the implicit assumption that ideas make a difference somehow. The account that I enlist emerges from world society analysis. According to that stance, ideas are causally efficacious, in contrast, say, with materialist understandings in the Marxist tradition. Also, world society analysis seeks to understand the efficacy of ideas in a global context, by way of contrast, for instance, with international relations realists who believe it is mostly interests backed by power that explain change in the international domain. World society analysis has illuminating implications for political philosophy.

We explore the motivation for a public reason standpoint that comes from what Rawls calls the “burdens of judgment,” challenges in interpreting our moral lives that generate a plurality of interpretations. These burdens and the implied fact of reasonable pluralism motivate a public reason view. Defenders of comprehensive doctrines are not asked to abandon talk about truth or correctness, but to realize that competent reasoners invariably embrace different doctrines. This approach suits an era of global interconnectedness in the face of diversity but also faces stiff resistance. We then connect the Rawlsian account of public reason for the domestic case to the grounds-of-justice approach. The key idea is that the grounds can be understood as being included in an overlapping consensus. Then, Rawls’s construction for public reason carries over to the global level. This development of global public reason also completes the account of the political philosopher from Part I.

Rawls’s conceptualization is the culmination of reflection on the social question over 200 years. The grounds-of-justice approach unifies a broad range of thinking about justice at the global level as it has unfolded over millennia, reflecting the current stage of the great tale of humanity. The animating concern behind human rights is protection of personal inviolability and subsistence from patterns of societal organization that might threaten them. Human rights focus on the status and well-being of any one person rather than an overall distributive picture. The global dimensions of the social question have long gone unappreciated. The global can no longer be an afterthought but is imminent in reflection on justice also in more confined spaces. The default contemporary understanding of justice is global in scope, complex in structure, stringent in demandingness, and extensive in its reach in a manner that is best understood in a public reason sense.