Book I chapter 19

Of the refutations, then, that depend upon ambiguity¹ and amphiboly some contain some question with more than one meaning, while others contain a conclusion bearing a number of senses: e.g. in the proof that ‘speaking of the silent’ is possible, the conclusion has a double meaning, while in the proof that ‘he who knows does not understand what he knows’ one of the questions contains an amphiboly. Also the double-edged saying is true in one context but not in another: it means something that is and something that is not.

Whenever, then, the many senses lie in the conclusion no refutation takes place unless the sophist secures as well the contradiction of the conclusion he means to prove; e.g. in the proof that ‘seeing of the blind’ is possible: for without the contradiction there was no refutation. Whenever, on the other hand, the many senses lie in the questions, there is no necessity to begin by denying the double-edged premiss: for this was not the goal of the argument but only its support. At the start, then, one should reply with regard to an ambiguity, whether of a term or of a phrase, in this manner, that ‘in one sense it is so, and in another not so’, as e.g. that ‘speaking of the silent’ is in one sense possible but in another not possible: also that in one sense ‘one should do what must needs be done’, but not in another: for ‘what must needs be’ bears a number of senses. If, however, the ambiguity escapes one, one should correct it at the end by making an addition to the question: ‘Is speaking of the silent possible?’ ‘No, but to speak of while he is silent is possible.’ Also, in cases which contain the ambiguity in their premisses, one should reply in like manner: ‘Do people-then not understand what they know? “Yes, but not those who know it in the manner described’: for it is not the same thing to say that ‘those who know cannot understand what they know’, and to say that ‘those who know something in this particular manner cannot do so’. In general, too, even though he draws his conclusion in a quite unambiguous manner, one should contend that what he has negated² is not the fact which one has asserted but only its name; and that therefore there is no refutation.

1 ambiguity   

n.模棱两可；意义不明确

参考例句：

• The telegram was misunderstood because of its ambiguity.由于电文意义不明确而造成了误解。
• Her answer was above all ambiguity.她的回答毫不含糊。

2 negated   

v.取消( negate的过去式和过去分词 )；使无效；否定；否认

参考例句：

• Our historical right to rule ourselves as a people had been negated. 我们被剥夺了作为一个民族治理自己国家的历史权利。 来自辞典例句
• Thus far we have negated frictional effects in the harmonic oscillator. 到现在为止，我们一直没有考虑谐和振荡器中的摩擦效应。 来自辞典例句