Cosmopolitan ethics begins with a proposition most moral philosophy prefers to avoid: you have obligations to people you will never meet. Not aspirational obligations. Not the soft duties of charitable feeling that can be satisfied by an annual donation and a moment of seasonal guilt. Genuine obligations — claims that strangers have on your behavior, your choices, your institutional designs, by virtue of being human beings affected by what you do. Applied to AI, the framework identifies a structural truth the discourse consistently evades: the people who benefit most from AI are benefiting from a structure that imposes costs on others. Those others are strangers. Most of the beneficiaries will never meet them. The cosmopolitan obligation is real. The Luddites of 1812 were destroyed in part because the people who benefited from the power looms acknowledged no obligation to the displaced. The pattern is not historical. It is contemporary.
The resistance to stranger-obligation comes from two directions. Communitarians argue that genuine obligation requires genuine relationship — you can owe duties to family, community, nation, but not to strangers. Libertarians argue that obligation requires consent — you cannot be bound by duties you did not choose. Appiah rejects both. The boundaries of community have never been fixed; every moral expansion in history has involved recognizing people previously classified as strangers as within the circle of obligation. And benefit from a structure that harms others incurs obligation regardless of whether the benefit was sought.
The parallel to AI is precise. The productivity gains Segal documents are real. The builders achieving them are not villains. But the gains have costs, and the costs fall on strangers — the junior developer not hired, the mid-career professional displaced before retraining is possible, the communities whose economic foundations are being restructured. The obligation is not charity. It is justice, arising from the structure of the situation.
Appiah's framework demands three concrete responses. First, visibility: the people bearing the costs must be seen as particular individuals, not statistics. Second, institutional response: retraining programs, safety nets, educational reform — built at the speed the transition demands. Third, moral imagination — the active effort to understand the world from the displaced stranger's perspective.
Acemoglu and Johnson in Power and Progress provide the historical evidence that makes the philosophical framework concrete. Across a thousand years of technological transitions, distributional consequences were determined not by the technology but by the institutional choices made during the transition. Technologies with strong institutions produced broadly shared prosperity. Technologies without produced concentrated wealth and widespread immiseration. The choices are being made now.
Appiah developed the stranger-obligation framework most fully in Cosmopolitanism: Ethics in a World of Strangers (2006). The framework draws on Kant's cosmopolitan writings while rejecting Kant's universalism-as-abstraction for a rooted universalism that acknowledges particular attachments while insisting on duties that extend beyond them.
Obligation is structural. It arises from the situation, not from the obligated party's feelings. Benefit from a system that harms others creates duty regardless of intent.
Visibility first. The people bearing the costs must be seen as particular individuals. Aggregate statistics perform a subtle moral erasure.
Institutions over intentions. Good intentions are necessary but insufficient. The obligation requires the construction of institutions that distribute transition costs justly.
Moral imagination. Genuine cosmopolitan concern requires active effort to understand the world from the perspective of those affected — not simulated stakeholder analysis but actual encounter.
The objection from effective altruism argues that impartial moral concern requires treating all strangers equally, which conflicts with Appiah's emphasis on particular attachment. Appiah's response is that rooted cosmopolitanism is not weakened impartialism but a different framework entirely — one that recognizes particular attachments as constitutive of moral agency while extending concern beyond them.