This discussion responds to important questions raised about my theory of fairness in the global economy by Christian Barry, Charles Beitz, A.J. Julius and Kristi Olson. I further elaborate how moral argument can be ‘internal’ to a social practice, how my proposed principles of fairness depend on international practice, how I can admit several relevant conceptions of ‘harm’ and why my account does not depend on a problematic conception of societal ‘endowments’.