Book I chapter 26

Refutations that depend on the definition of a refutation must, according to the plan sketched¹ above, be met by comparing together the conclusion with its contradictory², and seeing that it shall involve the same attribute in the same respect and relation and manner and time. If this additional question be put at the start, you should not admit that it is impossible for the same thing to be both double and not double, but grant that it is possible, only not in such a way as was agreed to constitute a refutation of your case. All the following arguments depend upon a point of that kind. ‘Does a man who knows A to be A, know the thing called A?’ and in the same way, ‘is one who is ignorant that A is A ignorant of the thing called A?’ ‘Yes.’ ‘But one who knows that Coriscus is Coriscus might be ignorant of the fact that he is musical, so that he both knows and is ignorant of the same thing.’ Is a thing four cubits long greater than a thing three cubits long?’ ‘Yes.’ ‘But a thing might grow from three to four cubits in length; ‘now what is ‘greater’ is greater than a ‘less’: accordingly the thing in question will be both greater and less than itself in the same respect.

1 sketched   

v.草拟（sketch的过去式与过去分词形式）

参考例句：

• The historical article sketched the major events of the decade. 这篇有关历史的文章概述了这十年中的重大事件。 来自《简明英汉词典》
• He sketched the situation in a few vivid words. 他用几句生动的语言简述了局势。 来自《现代汉英综合大词典》

2 contradictory   

adj.反驳的，反对的，抗辩的；n.正反对，矛盾对立

参考例句：

• The argument is internally contradictory.论据本身自相矛盾。
• What he said was self-contradictory.他讲话前后不符。