* * * * * Having thus achieved internal proof of development of doctrines in Plotinos, by examination of his views about Matter, we may with some confidence state that the externally known facts of the life of no philosopher lend themselves to such a progress of opinions more readily than that of Plotinos. His biographer, Porphyry, as we have seen, had already given us a list of the works of three easily characterized periods in Plotinos's life: the period before Porphyry came to him, the period while Porphyry staid with him, and the later period when Plotinos was alone, and Porphyry was in retirement (or banishment?) in Sicily. An external division into periods is therefore openly acknowledged; but it remains for us to recall its significance. In the first place, the reader will ask himself, how does it come about that Plotinos is so dependent on Porphyry, and before him, on Amelius? The answer is that Plotinos himself was evidently somewhat deficient in the details of elementary education, however much proficiency in more general philosophical studies, and in independent thought, and personal magnetic touch with pupils he may have achieved. His pronunciation was defective, and in writing he was careless, so much so that he usually failed to affix proper headings or notice of definite authorship.[441] These peculiarities would to some extent put him in the power, and under the influence of his editors, and this explains why he was dependent on Porphyry later, and Amelius earlier.[442] These editors might easily have exerted potent, even if unconscious or merely suggestive influence; but we know that Porphyry did not scruple to add glosses of his own,[443] not to speak of hidden Stoic and Aristotelian pieces,[444] for he relied on Aristotle's "Metaphysics." Besides, Plotinos was so generally accused of pluming himself on writings of Numenius, falsely passed off as his own, that it became necessary for Amelius to write a book on the differences between Numenius and Plotinos, and for Porphyry to defend his master, as well as to quote a letter of Longinus on the subject;[445] but Porphyry does not deny that among the writings of the Platonists Kronius, Caius, and Attikus, and the Peripatetics Aspasius, Alexander and Adrastus, the writings of Numenius also were used as texts in the school of Plotinos (14). Having thus shown the influence of the editors of Plotinos, we must examine who and what they were. Let us however first study the general trend of the Plotinic career.