Ita cum philosophos expugnaverit, ac docuerit eos nihil scire, ipse quoque nomen philosophi perdidit; quia doctrina ejus est nihil scire. Nam qui alios reprehendit, quod nesciant, ipse debet sciens esse. Cum autem nihil sciat, quae perversitas, quaeve insolentia est, ob id ipsum se philosophum constituere, propter quod ceteros tollat? Possunt enim sic respondere: Si nihil nos scire convincis, et ideo non esse sapientes, quia nihil sciamus; ergone tu quidem es sapiens, quia te quoque confiteris nihil scire? Quid ergo promovit Arcesilas, nisi quod confectis omnibus philosophis, seipsum quoque eodem mucrone transfixit?
–Lactantius, Divinae Institutiones 3.5
So when [Arcesilas] expunged the philosophers and taught that they know nothing, he also lost the name of philosopher; since his teaching is that nothing is known. For he who reprehended others for not knowing, himself ought to be knowledgeable. Since however he knows nothing, what perversity or what insolence is it, to establish himself as a philosopher because of the very fact on account of which he dismisses the others? For they can respond thus: If you prove that we know nothing, and so are not wise, because we know nothing, are you even therefore wise, because you also confess to know nothing? Therefore what did Arcesilaus promote, except that when all the philosophers were done away with, he transfixed himself with his own sword?
–Lactantius, The Divine Instructions 3.5
And the reader will remember, I think, the following from Lucretius, which has appeared in these pages:
De Rerum Natura (On the Nature of Things) vv. 4.469–470:
Denique nil sciri siquis putat, id quoque nescitan sciri possit, quoniam nil scire fatetur.
In the end, then, if someone thinks nothing is known, he doesn’t even know this, whether it can be known, since he professes to know nothing.
This is what Jürgen Habermas, one of the greater philosophers of our time, has called the “performative contradiction”.
Thanks, dear reader, should you ever find me, for being my gadfly.