  Marcus often tells himself, ‘erase (exaleipsai) your impressions (phantasiai)’ (v.2, vii.29, viii.29, ix.7, cf. ii.5, iii.16, v.36). According to Stoic epistemology, things in the world impress images of themselves on human and animal souls, as shapes can impress themselves on a wax tablet. Human beings may also assent to or withhold assent from these impressions; judgments are the result of our assenting to impressions, or more precisely to the propositional articulations of our impressions. While assent is voluntary, impressions are not (cf. Epictetus fr. 9). So clearly we can’t erase our impressions in the sense of simply wiping them out, but then what is Marcus telling himself to do? In exchanges with Academic skeptics, the Stoics say that the wise person does not assent except to impressions that represent accurately the thing in the world that is their cause (‘kataleptic’ impressions); how does Marcus’ injunction to ‘erase’ impressions relate to this standard?