The paper brings Froebel’s philosophy into conversation with that of Deleuze. We focus on the fold and on self-activity as key concepts that hold a special place in the monist philosophies of both thinkers. One point at which their (very different) ontologies coincide is their conceptualization of a cosmos in which everything is ultimately in relation. The philosophical convergences of such different thinkers in different eras are mapped in relation to the influences of a shared lineage with some earlier hermetic and romantic strains of thought. Both Froebel and Deleuze conceive of subjectivity as a relation of dynamic folding and unfolding of inner life and external world. The fold, as the operation that brings outside and inside together ...