It is in this point of view--in reference to logical theory--that the Megaric philosophers have not been fairly appreciated. They, or persons reasoning in their manner, formed one essential encouragement and condition to the formation of any tolerable logical theory. They administered, to minds capable and constructive, that painful sense of contradiction, and shock of perplexity, which Sokrates relied upon as the stimulus to mental parturition--and which Plato extols as a lever for raising the student to general conceptions.[39] Their sophisms were not intended to impose upon any one, but on the contrary, to guard against imposition.[40] Whoever states a fallacy clearly and nakedly, applying it to a particular case in which it conducts to a conclusion known upon other evidence not to be true--contributes to divest it of its misleading effect. The persons most liable to be deceived by the fallacy are those who are not forewarned:--in cases where the premisses are stated not nakedly, but in an artful form of words--and where the conclusion, though false, is not known beforehand to be false by the hearer. To use Mr. John Stuart Mill's phrase,[41] the fallacy is a case of apparent evidence mistaken for real evidence: you expose it to be evidence only apparent and not real, by giving a type of the fallacy, in which the conclusion obtained is obviously false: and the more obviously false it is, the better suited for its tutelary purpose. Aristotle recognises, as indispensable in philosophical enquiry, the preliminary wrestling into which he conducts his reader, by means of a long string of unsolved difficulties or puzzles--([Greek: a)po/riai]). He declares distinctly and forcibly, that whoever attempts to lay out a positive theory, without having before his mind a full list of the difficulties with which he is to grapple, is like one who searches without knowing what he is looking for; without being competent to decide whether what he hits upon as a solution be really a solution or not.[42] Now that enumeration of puzzles which Aristotle here postulates (and in part undertakes, in reference to Philosophia Prima) is exactly what the Megarics, and various other dialecticians (called by Plato and Aristotle Sophists) contributed to furnish for the use of those who theorised on Logic. [Footnote 39: Plato, Republic, vii. pp. 523 A, 524. [Greek: ta\ me\n e)n tai=s ai)sthê/sesin ou) parakalou=nta tê\n no/êsin ei)s e)pi/skepsin, ô(s i(kanô=s u(po\ tê=s ai)sthê/seôs krino/mena--ta\ de\ panta/pasi diakeleuo/mena e)kei/nên e)piske/psasthai, ô(s tê=s ai)sthê/seôs ou)de\n u(gie\s poiou/sês . . . Ta\ me\n ou) parakalou=nta, o(/sa mê\ e)kbai/nei ei)s e)nanti/an ai)/sthêsin a(/ma; ta\ d' e)kbai/nonta, ô(s parakalou=nta ti/thêmi, e)peida\n ê( ai)/sthêsis mêde\n ma=llon tou=to ê)\ to\ e)nanti/on dêloi=]. Compare p. 524 E: the whole passage is very interesting.]