The trick of claiming certitude as a way of avoiding serious persuasion is Plato’s Trope. I hold in my hand a proof, such as they have in mathematics–not the wretched opinions they trade in the courts of law–that kings should be philosophers and philosophers kings. “Don’t you know that first-order predicate logic is enough to build a world upon?” the Platonist will ask in 1920. Or, to give examples from economic rhetoric, “Don’t you know that market capitalism is optimal, according to the blackboard proof?” These have all been presented as demonstrative, but in each case the so-called demonstration has been merely an excuse not to argue on grounds that would persuade reasonable people.
Donald McClosky, “Rhetorical” 1993