_Socrates._ The same person who had been aware of the false one, or some other? _Ion._ The same, clearly. _Socrates._ That is, some one who understood arithmetic? _Ion._ Certainly. _Socrates._ Among a number of persons giving their opinions on the wholesomeness of different foods, whether would one person be capable to pronounce upon the rectitude of the opinions of those who judged rightly, and another on the erroneousness of those which were incorrect, or would the same person be competent to decide respecting them both? _Ion._ The same, evidently. _Socrates._ What would you call that person? _Ion._ A physician. _Socrates._ We may assert then, universally, that the same person who is competent to determine the truth, is competent also to determine the falsehood of whatever assertion is advanced on the same subject; and, it is manifest, that he who cannot judge respecting the falsehood, or unfitness of what is said upon a given subject, is equally incompetent to determine upon its truth or beauty? _Ion._ Assuredly. _Socrates._ The same person would then be competent or incompetent for both? _Ion._ Yes. _Socrates._ Do you not say that Homer and the other poets, and among them Hesiod and Archilochus, speak of the same things, but unequally; one better and the other worse? _Ion._ And I speak truth. _Socrates._ But if you can judge of what is well said by the one, you must also be able to judge of what is ill said by another, inasmuch as it expresses less correctly. _Ion._ It should seem so. _Socrates._ Then, my dear friend, we should not err if we asserted that Ion possessed a like power of illustration respecting Homer and all other poets; especially since he confesses that the same person must be esteemed a competent judge of all those who speak on the same subjects; inasmuch as those subjects are understood by him when spoken of by one, and the subject-matter of almost all the poets is the same. _Ion._ What can be the reason then, O Socrates, that when any other poet is the subject of conversation I cannot compel my attention, and I feel utterly unable to declaim anything worth talking of, and positively go to sleep? But when any one makes mention of Homer, my mind applies itself without effort to the subject; I awaken as if it were from a trance, and a profusion of eloquent expressions suggest themselves involuntarily? _Socrates._ It is not difficult to suggest the cause of this, my dear friend. You are evidently unable to declaim on Homer according to art and knowledge; for did your art endow you with this faculty, you would be equally capable of exerting it with regard to any other of the poets. Is not poetry, as an art or a faculty, a thing entire and one? _Ion._ Assuredly. _Socrates._ The same mode of consideration must be admitted with respect to all arts which are severally one and entire. Do you desire to hear what I understand by this, O Ion?