 Consider two concepts that are often invoked in debates about the justification for public health interventions- the ‘common good’ and the ‘public good.’ These terms are polysemous, and this sometimes leads to confusion. Some uses of these terms are associated with political values as, for example, when ‘the common good’ refers to values shared or pursued collectively by all members of a community. Many anti-reductionists will invoke ‘the common good,’ so understood, to justify public health interventions and policies. For instance, some argue that all members of the same community, qua members of the same community, have an interest in living in a social grouping in which all enjoy a high degree of health. Economists, by contrast, use ‘common good’ to refer to a pooled resource that is rivalrous (one person’s usage diminishes the ability of others to use it) but non-excludable (it is quite difficult to exclude others from using it). In some public health contexts, safe water, food and drugs can be understood as common goods in this sense.