 Arcesilaus calls into question whether there are impressions of this kind. His main point seems to be that there could be an impression that is phenomenologically indistinguishable from cognitive impressions, but nevertheless misrepresents the matters it gives an impression about. To use an example that may derive from Carneades (see section 3.2), there is no impression of a given egg such that no impression of any other egg could be phenomenologically indistinguishable from it (Shogry 2018 and 2021, Machek and Veres forthcoming). Assuming that some clauses in Stoic definitions respond to specific skeptic challenges, the following clause, added to a shorter definition, appears to speak to these cases: “and of such a kind as could not arise from what is not” (Long and Sedley (1987) [= LS] 40; DL 7.46, 54; Cicero Acad. 1.40–1, 2.77–8; SE M 7.247–52). Absent a criterion of truth, Arcesilaus’ skeptic suspends judgment about everything (PH 1.232). Reason itself, Arcesilaus thinks, demands such suspension.