THREE:It was their habit of teaching rhetoric as an art which raised the fiercest storm of indignation against Protagoras and his colleagues. The endeavour to discover rules for addressing a tribunal or a popular assembly in the manner best cal94culated to win their assent had originated quite independently of any philosophical theory. On the re-establishment of order, that is to say of popular government, in Sicily, many lawsuits arose out of events which had happened years before; and, owing to the lapse of time, demonstrative evidence was not available. Accordingly, recourse was had on both sides to arguments possessing a greater or less degree of probability. The art of putting such probable inferences so as to produce persuasion demanded great technical skill; and two Sicilians, Corax and Tisias by name, composed treatises on the subject. It would appear that the new-born art was taken up by Protagoras and developed in the direction of increased dialectical subtlety. We are informed that he undertook to make the worse appear the better reason; and this very soon came to be popularly considered as an accomplishment taught by all philosophers, Socrates among the rest. But if Protagoras merely meant that he would teach the art of reasoning, one hardly sees how he could have expressed himself otherwise, consistently with the antithetical style of his age. We should say more simply that a case is strengthened by the ability to argue it properly. It has not been shown that the Protagorean dialectic offered exceptional facilities for maintaining unjust pretensions. Taken, however, in connexion with the humanistic teaching, it had an unsettling and sceptical tendency. All belief and all practice rested on law, and law was the result of a convention made among men and ultimately produced by individual conviction. What one man had done another could undo. Religious tradition and natural right, the sole external standards, had already disappeared. There remained the test of self-consistency, and against this all the subtlety of the new dialectic was turned. The triumph of Eristic was to show that a speaker had contradicted himself, no matter how his statements might be worded. Moreover, now that reference to an objective reality was disallowed, words were put in the place95 of things and treated like concrete realities. The next step was to tear them out of the grammatical construction, where alone they possessed any truth or meaning, each being simultaneously credited with all the uses which at any time it might be made to fulfil. For example, if a man knew one thing he knew all, for he had knowledge, and knowledge is of everything knowable. Much that seems to us tedious or superfluous in Aristotles expositions was intended as a safeguard against this endless cavilling. Finally, negation itself was eliminated along with the possibility of falsehood and contradiction. For it was argued that nothing had no existence and could not be an object of thought.71
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