with arguments, and this will sometimes indeed be necessary, at others, appear to be so, but sometimes neither apparent, nor necessary. Now it is necessary, when the respondent, denying some one of those things which are useful to the thesis, the arguments are directed against this, which happens to be a thing of that kind, against which it is possible to abound with arguments. In like manner, when some one by making an abduction to a certain thing, through what is laid down, endeavours to subvert (that thing), for this being subverted, the proposition is also subverted. On the other hand, it appears to be necessary when it seems indeed useful and appropriate to the thesis, yet is not so to that against which the arguments are adduced, whether he who sustains the argument denies, or whether by a probable abduction through the thesis against it, he endeavours to subvert it. The remainder is when that against which the arguments are advanced, is neither necessary nor appears to be so, but it happens that the respondent is sophistically confuted in another respect. We must however be cautious about the last of the above-mentioned modes, for it seems to be altogether remote and foreign from dialectic, wherefore the respondent must not be displeased, but should admit whatever are not useful to the thesis, signifying what do not appear to him to be true, though he admits them; for it happens generally that those who interrogate are more perplexed, when every thing of this kind is admitted, if they do not conclude.
Further, every one who states any thing, in some way states many things, since many are conse-
