Unlike wealth, which is mainly instrumental in facilitating other life goals, health represents both instrumental and intrinsic value – the necessary condition of ‘normal functioning’ and the substance and quality of life itself (Frankena, 1976; Nussbaum, 1999; Rid, 2008; Sen, 2017). As such, health enjoys a special status in the question of social justice.

It is widely agreed that egregious inequality in people's health and lifespan is unattractive, undesirable and even morally offensive. But the idea of an enforceable level of equality in what is widely viewed as a quintessentially fateful human property is equally generally regarded as both practically implausible and unacceptably intrusive in the space of individual freedom (Venkatapuram, 2019). Between the fundamental affront of avoidably unequal lives and the impossibility of strictly equal existence, political philosophy and public policy have struggled – and continue to struggle – with the specific terms of a health justice (Arneson, 1989; Anand et al, 2004; Boylan, 2004; van Raalte et al, 2018).

Rawls rejects health, viewing it as a natural good – a matter of individual luck randomly distributed and thus provoking no question of fairness in distribution. Sen and colleagues recognise health as a key dimension of social justice, but with notable differences in the extent to which society can be held responsible – ranging from supporting the opportunity to be healthy through adequate provision of the basics of human development, but without any guarantee of a healthy life outcome, to an Aristotelian list of social conditions on which health depends, but with diminishing clarity, as the list lengthens, about which public institutions, if any, can be reasonably held accountable for their provision (Daniels, 1985; Sachs, 2010; Sen, 2010; Nussbaum, 2011; Daniels, 2012; Kelleher, 2013).

Loaded with overwhelming ambiguity, the idea of health as justice has become enmired in a kind of ethical no-man's land. At the heart of the problem is an intense uncertainty about physical causation and moral responsibility – uncertainty about how far health is the reflection of individual characteristics or societal arrangements; about how much health and lifespan reflect lifestyle choices or brute luck, and how much they are the net effect of the many intersecting ways society shapes our lives;