The interest in the ethics of health inequalities rather than just health or healthcare is becoming more widespread and gaining momentum. In particular, health researchers and others concerned about the social determinants and social gradients (that is, inequalities) of preventable ill-health and premature mortality are increasingly drawing on the normative domain of social ethics and justice. At the same time, political philosophers are extending their traditional scope of concern about social justice and inequality into the domain of health. Ethical evaluation of global health inequalities, then, requires integrating reasoning across empirical health sciences and normative ethics and extending the scope to include all societies and the entire human species. While this description may initially suggest a two-step – first domestic, then global – reasoning process, it is not only plausible but perhaps logically and ethically necessary that both empirical and normative analyses of health and health inequalities require starting with a global perspective.

The flip side of the ethics of (global) health inequalities being of interest to diverse actors and encompassing diverse concerns is that discussions can cut across each other, misunderstandings across disciplines or the research versus policy divide can give rise to antipathies, not to mention that a wide range of philosophical and ethical issues as well as related ambiguities become enmeshed. The joining up of health, inequality and ethics increases complexity multiplicatively rather than additively. For example, while stark numerical inequalities in health outcomes may initially provoke moral indignation, why exactly are health inequalities a moral worry?