A fundamental, neglected problem of relation to the individual and marginalised groups exists within Hart’s description of the foundational rule of recognition for legal systems. This article aims to establish the need for a relational foundationalism for law that engages with the concrete other, given the limitations of Hart’s foundationalist account of the rule of recognition which assumes an abstract, generalised other. This leads to a focus on a contextual process of recognition, as a relation to the individual and marginalised groups, resonant with conceptions of Kantian dignity that treat a person as an end and not a means. Rejecting Teubner’s non-foundationalist focus on communication, as well as Raz’s reduction of the rule of recognition to include solely legal officials, it is argued that relational foundations of legal systems do not exist and are needed. A subsidiary argument is that the UN framework on the right to the highest attainable standard of health is a significant, though preliminary, step towards a relational foundationalism; it engages with the concrete other, providing indicators disaggregated by at least sex, race, ethnicity, rural/urban, and socio-economic status, as well as a dialogical process of voice with the relevant community, including marginalised groups.