The public/private distinction is central to higher education but there is no consensus on "public." In neo-classical economic theory, Samuelson distinguishes non-market goods (public) that cannot be produced for profit, from market-based activity (private). This provides a basis for identifying the minimum necessary public expenditure, but does not effectively encompass collective goods, or normative elements. In political theory "public" is often understood as state ownership and/or control. Dewey regards social transactions as "public" when they have relational consequences for persons other than those directly engaged, and so become matters of state concern. This is more inclusive than Samuelson but without limit on costs. Neither definition is wholly satisfactory, each offers something, and each can be used to critically interrogate the other. The article synthesises the two approaches, applying the resulting analytical framework with four quadrants (civil society, social democracy, state quasi-market and commercial market) to higher education and research.