Full Idea
Fifteenth mode: proofs often presuppose the thing to be proved.
Clarification
One of the 'modes of scepticism'
Gist of Idea
Proofs often presuppose the thing to be proved (Mode 15)
Source
report of Agrippa (fragments/reports [c.60]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.10
Book Reference
Diogenes Laertius: 'Diogenes Laertius', ed/tr. Yonge,C.D. [Henry G. Bohn 1853], p.413