XVII. Ammonius, as one who himself gave Mathematics no mean place in Philosophy, was pleased at the course the conversation was taking, and said: ‘It is not worth our while to answer our young friends with too absolute accuracy on these points; I will only observe that any one of the numbers will provide not a few points for those who choose to sing its praises. [Sidenote: F] Why speak about the others? Apollo’s holy “Seven” will take up all one day before we have exhausted its powers. Are we then to show the Seven Wise Men at odds with common usage, and “the time which runs”[72], and to suppose that they ousted the “Seven” from its pre-eminence before the God, and consecrated the “Five” as perhaps more appropriate? ‘My own view is that the letter signifies neither number, nor [Sidenote: 392] order, nor conjunction, nor any other omitted part of speech; it is a complete and self-operating mode of addressing the God; the word once spoken brings the speaker into apprehension of his power. The God, as it were, addresses each of us, as he enters, with his “KNOW THYSELF”, which is at least as good as “Hail”. We answer the God back with “EI” (Thou Art), rendering to him the designation which is true and has no lie in it, and alone belongs to him, and to no other, that of BEING. XVIII. ‘For we have, really, no part in real being; all mortal nature is in a middle state between becoming and perishing, and presents but an appearance, a faint unstable image, of itself. If you strain the intellect, and wish to grasp this, it [Sidenote: B] is as with water; compress it too much and force it violently into one space as it tries to flow through, and you destroy the enveloping substance; even so when the reason tries to follow out too closely the clear truth about each particular thing in a world of phase and change, it is foiled, and rests either on the becoming of that thing or on its perishing; it cannot apprehend anything which abides or really is. “It is impossible to go into the same river twice”, said Heraclitus;[73] no more can you grasp mortal being twice, so as to hold it. So sharp and so swift is change; it scatters and brings together again, nay not again, no nor afterwards; even while it is being formed it fails, [Sidenote: C] it approaches, and it is gone. Hence becoming never ends in being, for the process never leaves off, or is stayed. From seed it produces, in its constant changes, an embryo, then an infant, then a child; in due order a boy, a young man; then a man, an elderly man, an old man; it undoes the former becomings and the age which has been, to make those which come after. Yet we fear (how absurdly!) a single death, we who have died so many deaths, and yet are dying. For it is not only that, as Heraclitus[74] would say, “death of fire is birth of air”, and “death of air is birth of water”; the thing is much clearer in [Sidenote: D] our own selves. The man in his strength is destroyed when the old man comes into being,