<p>Metaphysical foundationalism is the view that ground is well-founded. Despite its reputation as the default view of the general structure of reality, it is a view with few explicit defenders whose theoretical virtues remain largely unexplored. This paper makes an abductive case for metaphysical foundationalism, which lays emphasis on these virtues as relevant to theory choice. As part of the discussion I outline a new theory of ground and of generative relations, and describe a formalism for regimenting it.</p>