Full Idea
Arcesilaus said that no presentation proceeding from a true object is such that a presentation proceeding from a false one might not also be of the same form. This is the one argument that has held the field down to the present day.
Gist of Idea
A false object might give the same presentation as a true one
Source
report of Arcesilaus (fragments/reports [c.275 BCE]) by M. Tullius Cicero - Academica II.24.77
Book Reference
Cicero: 'De Natura Deorum and Academica (XIX)', ed/tr. Rackham,H. [Harvard Loeb 1933], p.565