each of you avoids answering me that question alone which was the only one which I wished to have answered, I will tell you what each of you are thinking of; for both you, O woman, wish to have the best husband, and you, O Xenophon, most exceedingly desire to have the most excellent wife.  Wherefore, unless you both so contrive matters that there shall not be on the whole earth a more excellent man or a more admirable woman, then in truth you will at all times desire above all things that which you think to be the best thing in the world, namely, that you, O Xenophon, may be the husband of the best possible wife; and you, O woman, that you may be married to the most excellent husband possible.”  After they had declared their assent to these far from doubtful propositions, it followed, on account of the resemblance of the cases, that if any one had separately asked them about some doubtful point, that also would have been admitted as certain, on account of the method employed in putting the question.

This was a method of instruction which Socrates used to a great extent, because he himself preferred bringing forward no arguments for the purpose of persuasion, but wished rather that the person with whom he was disputing should form his own conclusions from arguments with which he had furnished himself, and which he was unavoidably compelled to approve of from the grounds which he had already assented to.

XXXII.  And with reference to this kind of persuasion, it appears to me desirable to lay down a rule, in the first place, that the argument which we bring forward by way of simile, should be such that it is impossible to avoid admitting it.  For the premiss on account of which we intend to demand that that point which is doubtful shall be conceded to us, ought not to be doubtful itself.  In the next place, we must take care that that point, for the sake of establishing which the induction is made, shall be really like those things which we have adduced before as matters admitting of no question.  For it will be of no service to us that something has been already admitted, if that for the sake of which we were desirous to get that statement admitted be unlike it; so that the hearer may not understand what is the use of those original inductions, or to what result they tend.

For the man who sees that, if he is correct in giving his assent to the thing about which he is first asked, that thing also to which he does not agree must unavoidably be admitted by him, very often will not allow the examination to proceed any further, either by not answering at all, or by answering wrongly.  Wherefore it is necessary that he should, by the method in which the inquiry is conducted, be led on without perceiving it, from the admissions which he has already made, to admit that which he is not inclined to admit, and at last he must either decline to give an answer, or he must admit what is wanted, or he must deny it.  If the proposition be denied, then we must either show its resemblance to those things which have been already admitted or we must employ some other induction.  If it be granted, then the argumentation may be brought to a close.  If he keeps silence, then an answer must be extracted, or, since silence is very like a confession, it may be as well to bring the discussion to a close, taking the silence to be equivalent to an admission.