It is plain from Aristotle's own words[64] that he intended these four chapters (xix.-xxii.) as a confirmation of what he had already asserted in chapter iii. of the present treatise, and as farther refutation of the two distinct classes of opponents there indicated: (1) those who said that everything was demonstrable, demonstration in a circle being admissible; (2) those who said that nothing was demonstrable, inasmuch as the train of predication upwards, downwards, and intermediate, was infinite. Both these two classes of opponents agreed in saying, that there were no truths immediate and indemonstrable; and it is upon this point that Aristotle here takes issue with them, seeking to prove that there are and must be such truths. But I cannot think the proof satisfactory; nor has it appeared so to able commentators either of ancient or modern times--from Alexander of Aphrodisias down to Mr. Poste.[65] The elaborate amplification added in these last chapters adds no force to the statement already given at the earlier stage; and it is in one respect a change for the worse, inasmuch as it does not advert to the important distinction announced in chapter iii., between universal truths known by Induction (from sense and particulars), and universal truths known by Deduction from these. The truths immediate and indemonstrable (not known through a middle term) are the inductive truths, as Aristotle declares in many places, and most emphatically at the close of the Analytica Posteriora. But in these chapters, he hardly alludes to Induction. Moreover, while trying to prove that there must be immediate universal truths, he neither gives any complete list of them, nor assigns any positive characteristic whereby to identify them. Opponents might ask him whether these immediate universal truths were not ready-made inspirations of the mind; and if so, what better authority they had than the Platonic Ideas, which are contemptuously dismissed. [Footnote 64: Analyt. Post. I. xxii. p. 84, a. 32: [Greek: o(/per e)/phame/n tinas le/gein kat' a)rcha/s], &c.] [Footnote 65: See Mr. Poste's note, p. 77, of his translation of this treatise. After saying that the first of Aristotle's _dialectical_ proofs is faulty, and that the second is a _petitio principii_, Mr. Poste adds, respecting the so-called _analytical_ proof given by Aristotle:--"It is not so much a proof, as a more accurate determination of the principle to be postulated. This postulate, the existence of first principles, as concerning the constitution of the world, appears to belong properly to Metaphysics, and is merely borrowed by Logic. See Metaph. ii. 2, and Introduction." In the passage of the Metaphysica ([Greek: a]. p. 994) here cited the main argument of Aristotle is open to the same objection of _petitio principii_ which Mr. Poste urges against Aristotle's second _dialectical_ argument in this place.