[Side-note: Mistake of supposing fallacies to have been invented and propagated by Athenian Sophists--they are inherent inadvertencies and liabilities to error, in the ordinary process of thinking. Formal debate affords the best means of correcting them.] The true character of these fallacies is very generally overlooked by the Platonic critics, in their appreciation of the Euthydêmus; when they point our attention to the supposed tricks and frauds of the persons whom they called Sophists, as well as to mischievous corruptions alleged to arise from Eristic or formal contentious debate. These critics speak as if they thought that such fallacies were the special inventions of Athenian Sophists for the purposes of Athenian Eristic: as if such causes of error were inoperative on persons of ordinary honesty or intelligence, who never consulted or heard the Sophists. It has been the practice of writers on logic, from Aristotle down to Whately, to represent logical fallacies as frauds devised and maintained by dishonest practitioners, whose art Whately assimilates to that of jugglers. This view of the case appears to me incomplete and misleading. It substitutes the rare and accidental in place of the constant and essential. The various sophisms, of which Plato in the Euthydêmus gives the _reductio ad absurdum_, are not the inventions of Sophists. They are erroneous tendencies of the reasoning process, frequently incident to human thought and speech: specimens of those ever-renewed "inadvertencies of ordinary thinking" (to recur to a phrase cited in my preface), which it is the peculiar mission of philosophy or "reasoned truth" to rectify. Moreover the practice of formal debate, which is usually denounced with so much asperity--if it affords on some occasions opportunity to produce such fallacies, presents not merely equal opportunity, but the only effective means, for exposing and confuting them. Whately in his Logic,[60] like Plato in the Euthydêmus, when bringing these fallacies into open daylight in order that every one may detect them, may enliven the theme by presenting them as the deliberate tricks of a Sophist. Doubtless they are so by accident: yet their essential character is that of infirmities incident to the _intellectus sibi permissus_: operative at Athens before Athenian Sophists existed, and in other regions also, where these persons never penetrated.]