This paper will explore the connections between the ontology and epistemology underlying Thomistic human rights theory and that of Cusa. The former will be chiefly represented by Maritain and his work connecting Thomistic philosophy with political theory. The latter will be chiefly represented through his De Pace Fidei and De Docta Ignorantia. Cusa's identification of the relationship between our understanding of Truth and the solid ontological ground underlying the full variety of social, cultural, and religious difference in human cultures will provide an additional support for the perspective on religious liberty and natural law articulated by Maritain. On this view, religious liberty is not only the privilege of a limited set of substantially similar traditions that have an overlapping consensus but 'reasonably' disagree on particulars. It is a fundamental component of the common good for all peoples and traditions.