While Aristotle located minerals, metals and other earth matter at the bottom of the hierarchical classification of beings, thus creating an insurmountable gap between the geological and animated ontologies, post-humanist approaches to the inorganic seek to bridge that gap and complicate the Aristotelian hierarchy of beings. Post-humanist approaches to the inorganic include thing-theory, object-oriented ontology, vital materialism and actor-network theory. I zoom onto Catherine Malabou’s concept of plasticity, which she develops in a post-humanist reading of Hegel, and which captures the capacity of organisms and objects to transform their internal parameters in response to the environment. I argue that Malabou’s ‘plasticity’ complicated and subverts the Aristotelian hierarchy of beings. Next, I apply these conceptual insights to ask about the place of non-human agency in collective and traumatic memory; through a close reading of Didi-Huberman’s Bark, I show that materiality and plasticity are aspects of mnemonic affordance