the ipsa, according to Cic.’s usage, is nom. and not abl.  Petrus Valentia (p. 301, ed Orelli) justly remarks that an art is not to be condemned as useless merely because it is unable to solve every problem presented to it.  He quotes Plato’s remarks (in Rep. II.) that the Expert is the man who knows exactly what his art can do and what it cannot.  Very similar arguments to this of Cic. occur in Sext., cf. esp. P.H. II. 175 and the words [Greek:  eautou estai ekkalyptikon].  For the mode in which Carneades dealt with Dialectic cf.  Zeller 510, 511.  The true ground of attack is that Logic always assumes the truth of phenomena, and cannot prove it.  This was clearly seen by Aristotle alone of the ancients; see Grote’s essay on the Origin of Knowledge, now reprinted in Vol II. of his Aristotle.

Sec.92. Nata sit:  cf. 28, 59. Loquendi:  the Stoic [Greek:  logike], it must be remembered, included [Greek:  rhetorike]. Concludendi:  [Greek:  tou symperainein] or [Greek:  syllogizesthai]. Locum:  [Greek:  topon] in the philosophical sense. Vitiosum:  49, n. Num nostra culpa est:  cf. 32. Finium:  absolute limits; the fallacy of the sorites and other such sophisms lies entirely in the treatment of purely relative terms as though they were absolute. Quatenus:  the same ellipse occurs in Orator 73. In acervo tritici:  this is the false sorites, which may be briefly described thus:  A asks B whether one grain makes a heap, B answers “No.”  A goes on asking whether two, three, four, etc. grains make a heap.  B cannot always reply “No.”  When he begins to answer “Yes,” there will be a difference of one grain between heap and no heap.  One grain therefore does make a heap.  The true sorites or chain inference is still treated in books on logic, cf.  Thomson’s Laws of Thought, pp 201—­203, ed 8. Minutatim:  cf.  Heindorf’s note on [Greek:  kata smikron] in Sophistes 217 D. Interrogati:  cf. 104.  In 94 we have interroganti, which some edd. read here. Dives pauper, etc.:  it will be easily seen that the process of questioning above described can be applied to any relative term such as these are.  For the omission of any connecting particle between the members of each pair, cf. 29, 125, T.D. I. 64, V. 73, 114, Zumpt Gram. 782. Quanto addito aut dempto:  after this there is a strange ellipse of some such words as id efficiatur, quod interrogatur. [Non] habemus:  I bracket non in deference to Halm, Madv. however (Opusc. I. 508) treats it as a superabundance of negation arising from a sort of anacoluthon, comparing In Vatin. 3, Ad Fam. XII. 24.  The scribes insert and omit negatives very recklessly, so that the point may remain doubtful.