 It is likely that Carneades refined and added to the stock of skeptical arguments employed in the Academy. They come in two groups. The first focus on the allegedly peculiar character, a kind of clarity, and strikingness, that belongs only to impressions that arise in the way specified by the definition of the cognitive impression, while the second tackle the requirement that cognitive impressions be distinct (Acad. 2.54–8, 84–6; S.E. M 7.408–11 = L&amp;S 40H). Arguments of the second type are based on the idea, denied by the Stoa, that two object might be exactly alike. If this were true, then even if impressions that captured their objects with complete accuracy by arising in the specified ideal conditions did possess a clarity that it was possible to acquire in no other way, it would not be possible to avoid errors of identification by confining one’s assent to impressions with the required clarity. One could, for instance, mistake someone for his identical twin. The only sure way to avoid error would then be to suspend judgment.