What-is was not generated from what-is-not, because what-is-not cannot give rise to anything in addition to itself. This is the first enunciation of the principle "out of nothing, nothing comes to be,"? which was implicit in earlier Greek thought even as far back as Hesiod and which afterwards, because of Parmenides, became a touchstone for subsequent Greek cosmogonies.These arguments show that coming to be from what-is-not is impossible, which is... relevant in the first stage of a cosmogony. The arguments say nothing of more familiar cases of coming to be, which can be described in terms of changes among already existing things.

I walked on to the next corner, sat on a bench at a bus stop, and read in my new book about Heraclitus. All things flow like a river, he said; nothing abides. Parmenides, on the other hand, believed that nothing ever changed, it only seemed so. Both views appealed to me.

The purest example of the Greek desire to comprehend, a desire which in him would have nothing to do with what was not strictly knowable. If later philosophers appear softer by comparison, it is perhaps because of a revivifying compromise they made, one more acceptable and more tolerant of the discourse we perhaps need; but, by the same token, one can perhaps be forgiven for sometimes thinking them dwarfed by the inhuman shadow of the master.

Greek philosophy returned for some time to the concept of the One in the teachings of Parmenides... His most important contribution... was, perhaps, that he introduced a purely logical argument into metaphysics. "One cannot know what is not—that is impossible—nor utter it; for it is the same thing that can be thought and that can be." Therefore, only the One is, and there is no becoming or passing away. Parmenides denied the existence of empty space for logical reasons. Since all change requires empty space... he dismissed change as an illusion.

What is clear is that Parmenides is making a conscious attempt at some kind of a new start. Like Descartes, he is trying to find an unassailable starting-point on which something further can be built. This search is understandable, given the intellectual situation of the time. The principles of the Milesians had yielded no one clearly true system, but a number of rival ones — in itself a scandal. Heraclitus had made the whole of cosmology suspect by revealing deep-seated contradictions at its heart. In the background, the Pythagoreans were directly or indirectly stimulating new lines of thought and using them, perhaps, for their own mysterious purposes.

Of the philosophers, Thales is vaguely reported to have taught that souls are immortal. But neither he nor his immediate successors... believed in the immortality of particular souls... This doctrine belongs to the Orphic tradition. In Heracleitus and Parmenides we find the two doctrines of immortality... implicit in mysticism, separated... for the first time. Heracleitus is the champion of the Dionysiac... life and death... in an unending cycle; Parmenides, under Orphic influence, teaches... Soul has fallen from... light and reality to the dark and unreal... bodily existence. This, however, is... only 'the way of opinion'... [Parmenides] feels.... that... substantiality... is not so easily got rid of. But he will not give up... eternal substance. The most interesting fragment of Parmenides... seems to enunciate, for the first time in Greek thought, the mystical doctrine of eternity as a timeless Now, as opposed to the popular... unending succession. 'There remains then only to give an account of one way—that real Being exists. Many signs... showing... it is unborn, indestructible, entire, unique, unshakable, and unending. It never was, and it never will be, since it is all together present in the Now, one and indivisible.' Empedocles... repudiates... Parmenides, probably on the ground that he reduces the world of time and change to nullity... thus leaves no pathway from appearance to reality. His doctrine of the soul’s exile and wanderings is... Orphic doctrine, which Pindar also gives... in the second Olympian Ode. The Soul sins by separating itself from God... from love and a choice of ' strife ’ in the place of harmony. The immortal Soul is... love and strife blended; the body... only an 'alien garment'... perishes at death. ...Empedocles describes the Soul as a ratio, or harmony ...the complex of...'strife'... bound... by the principle of unity...'love'...Parmenides ...may be ...rejects the Pytdhagorean doctrines ...finds truth in static materialism.

There is one story left, one road: that it is. And on this road there are very many signs that, being, is uncreated and imperishable, whole, unique, unwavering, and complete.

You must learn all things, both the unshaken heart of persuasive truth, and the opinions of mortals in which there is no true warranty.

Never will this prevail, that the things that are not are - bar your thought from this road of inquiry.

It is indifferent to me where I am to begin, for there shall I return again.

For it is the same thing that can be thought and that can be.

The only roads of enquiry there are to think of: one, that it is and that it is not possible for it not to be, this is the path of persuasion (for truth is its companion); the other, that it is not and that it must not be - this I say to you is a path wholly unknowable.

Do not let habit, born from experience, force you along this road, directing aimless eye and echoing ear and tongue; but judge by reason the much contested proof which I have spoken.