The aim of this paper is to raise the question of aging as an ontological question. In critical dialogue with Heidegger’s exploration of the question of being, the first half of the paper argues that fundamental ontology, due to the way it relies on a methodological operationalization of the ontological difference, will remain blind to the ontological generativity of the differences that aging makes. I introduce the term gerontological difference as a name for this kind of difference. The second half (...) of the paper explores the quasi-transcendental play of gerontological difference. Drawing on Foucault, Guenther and Agamben, I suggest that this play might be described in archaeological terms by tracing _the historical a priori_ in which age distinctions are operationalized biopolitically. Drawing on Derrida and Nancy, I argue that this archaeological view of the quasi-transcendental play of gerontological difference must be supplemented with a view of aging as material _différance_. According to this understanding of the quasi-transcendental play of gerontological difference, aging is an ontologically generative event that organizes intercorporeal tangles of coexistence and opens emergent fields of possible experience. (shrink)