The difficulty of harmonizing _our_ Aristotle with the Aristotle of the Catalogue is thus considerable. It has been so strongly felt in recent years, that one of the ablest modern critics altogether dissevers the two, and pronounces the works enumerated in the Catalogue not to belong to _our_ Aristotle. I allude to Valentine Rose, who in his very learned and instructive volume, '_Aristoteles Pseudepigraphus_,' has collected and illustrated the fragments which remain of these works. He considers them all pseudo-Aristotelian, composed by various unknown members of the Peripatetic school, during the century or two immediately succeeding the death of Aristotle, and inscribed with the illustrious name of the master, partly through fraud of the sellers, partly through carelessness of purchasers and librarians.[14] Emil Heitz, on the other hand, has argued more recently, that upon the external evidence as it stands, a more correct conclusion to draw would be (the opposite of that drawn by Rose, viz.): That the works enumerated in the Catalogue are the true and genuine; and that those which we possess, or most of them, are not really composed by Aristotle.[15] Heitz thinks this conclusion better sustained than that of Rose, though he himself takes a different view, which I shall presently mention. [Footnote 14: Valent. Rose, Aristoteles Pseudepigr. pp. 4-10. The same opinion is declared also in the earlier work of the same author, De Aristotelis Librorum Ordine et Auctoritate.] [Footnote 15: Heitz, Die Verlor. Schrift. des **Ar. pp. 29, 30.]