_Socr._ It is necessary, then, that he who means to deceive another, but
not be deceived himself, should be able to distinguish with accuracy the
similarity and dissimilarity of things.
_Phæ._ It is indeed necessary.
_Socr._ Will he be able, then, if ignorant of the truth of each
particular thing, to discern the smaller or greater similarity of the
thing of which he is ignorant, in other things?
_Phæ._ Impossible.
_Socr._ It is clear, therefore, that in the case of those who have
formed opinions contrary to the truth and are deceived, this error has
found its way in by means of certain resemblances.