In view of such tendencies, one hardly knows how much confidence is to be placed in Porphyry’s well-known picture of his master as one who lived so entirely for spiritual interests that he seemed ashamed of having a body at all. We are told that, as a consequence of this feeling, he avoided the subject of his past life, refused to let his portrait be painted, neglected the care of his health, and rigorously abstained from animal food, even when it was prescribed for him under the form of medicine.[424] All this may be true, but it is not very consistent with the special doctrines of Plotinus as recorded in his writings, nor should it be allowed to influence our interpretation of them. In his personal character and conduct he may have allowed himself to be carried away by the prevalent asceticism and superstition of the age; in his philosophy he is guided by the healthier traditions of Plato and Aristotle, and stands in declared opposition to the mysticism which was a negation of Nature and of life. How far Plotinus was indebted to Ammonius Saccas for his speculative ideas is another question with respect to which the Pythagoreanising tendencies of his biographer may possibly have contributed to the diffusion of a serious misconception. What Porphyry tells us is this. Before leaving Alexandria, Plotinus had bound himself by a mutual agreement with two of his fellow-pupils, Herennius and Origines (not the Christian Father, but a pagan philosopher of the same age and name), to keep secret what they had learned by listening to the lectures of Ammonius. Herennius, however, soon broke the compact, and Origines followed his example. Plotinus then considered that the engagement was at an end, and used the results of his studies under Ammonius as the basis of his conversational lectures in Rome, the substance of which, we are left to suppose, was subsequently embodied in his published writings. But, as Zeller has pointed out, this whole story bears a suspicious resemblance to what is related of the early Pythagorean school. There also the doctrines of the master were regarded by his disciples as a mystery which they pledged themselves to keep secret, and were only divulged through the infidelity of one among their number, Philolaus. And the same critic proves by a careful examination of what are known to have been the opinions of Origines and Longinus, both fellow-pupils of Plotinus, that they differed from him on some points of essential importance to his system. We cannot, therefore, suppose that these points were included in the teaching of their common master, Ammonius.[425] But if this be so, it follows that Plotinus was the real founder of the Neo-Platonic school; and, in all cases, his writings remain the great source whence our knowledge of its first principles is derived. III.