[https://www.ontology.co/parmenides.htm Parmenides' of Elea Way of Truth] with an annotated bibliography and a list of critical editions

[E]mpty space is nothing, nothing cannot be thought, and therefore cannot exist. What is, never came into being, nor is anything going to come into being in the future. "Is it or is it not?" If it is, then it is now, all at once.

He goes on to develop all the consequences of the admission that it is. It must be uncreated and indestructible. It cannot have arisen out of nothing; for there is no such thing as nothing. Nor can it have arisen from something; for there is no room for anything but itself.

The theory of Parmenides is the inevitable outcome of a corporeal monism, and his bold declaration of it ought to have destroyed that theory... If he had lacked courage to work out the prevailing views... to their logical conclusion... men might have gone on in the endless circle of opposition, rarefaction and condensation, one and many, for ever. ...[T]he thoroughgoing dialectic of Parmenides ...made progress possible. Philosophy must now cease [either] to be monistic or... corporealist. It could not cease to be corporealist; for the incorporeal was still unknown. It therefore ceased to be monistic, and arrived at the atomic theory... matter in motion.

The great novelty in the poem of Parmenides is the method of argument. He... asks what is the common of all the views... and he finds... this is the existence of what is not. ...[C]an [this] be thought ...it cannot. If you think... you must think of something. Therefore there is no nothing. Philosophy had not yet learned to make the admission that a thing might be unthinkable and nevertheless exist. Only that can be which can be thought (fr. 5); for thought exists for the sake of what is (fr. 8, 34). ...[I]f we ... allow nothing but what we can understand, we come into direct conflict with the evidence of our senses, ...a world of change and decay. So much the worse for the senses, says Parmenides.

Parmenides does not say a word about "Being" anywhere. The assertion that it is...amounts to ...the universe is a plenum; and ...there is no ...empty space ...From this it follows that there can be no such thing as motion. Instead of endowing the One with an impulse to change, as Herakleitos... Parmenides dismissed change as an illusion. He showed... if you take the One seriously you are bound to deny everything else. All previous solutions... had missed the point.

In the First Part of his poem... Parmenides [is] chiefly interested to prove... it is; but it is not... obvious... what it is... that is. He says simply, What is, is. ...[W]e are accustomed to ...distinctions between ...kinds and degrees of reality, and we do not see which ...is meant. Such distinctions... were... unknown in those days. "That which is," with Parmenides, is primarily... matter or body; only it is not matter ...distinguished from anything else. It is... spatially extended; for it is... spoken of as a (fr. 8, 40). ...Aristotle tells us ...Parmenides believed in none but a sensible reality, which ...includes any ...perceived if the senses were more perfect ...

Parmenides was... the first philosopher to expound his system in metrical language. ...[T]he only Greeks who ...wrote philosophy in verse were ...Parmenides and Empedokles; for Xenophanes was not primarily a philosopher... The fragments of Parmenides are preserved for the most part by Simplicius...

[P]ossibly... Parmenides believed in a "philosophic life" (§ 35), and... got the idea from the Pythagoreans; but there is very little trace... of his having been... affected by the religious side of Pythagoreanism. ...[T]here are traces of Orphic ideas in the poem ...Parmenides was a western Hellene, and he had probably been a Pythagorean, so it is not a little remarkable that he should be so free from the common tendency of his age and country. ...[L]ike most of the older philosophers, he took part in politics; and recorded that he legislated for his native city. Others add that the magistrates of Elea made the citizens swear every year to abide by the laws which Parmenides had given them.

What... was the step that placed the Ionian cosmologists... above the [] level of the Maoris? ...[T]he real advance made by the scientific men of Miletos was that they left off telling tales. They gave up the hopeless task of describing what was, when as yet there was nothing, and asked instead what all things really are now.The great principle which underlies all their thinking, though it is first put into words by Parmenides, is that Nothing comes into being out of nothing, and nothing passes away into nothing. They saw, however, that particular things were always coming into being and passing away again, and from this it followed that their existence was no true or stable one. The only things that were real and eternal were the original matter which passed through all these changes and the motion which gave rise to them, to which was... added that law of proportion or compensation...

The truth is, that these writings of mine were meant to protect the arguments of Parmenides against those who make fun of him and seek to show the many ridiculous and contradictory results which they suppose to follow from the affirmation of the one. My answer is addressed to the partisans of the many, whose attack I return with interest by retorting upon them that their hypothesis of the being of many, if carried out, appears to be still more ridiculous than the hypothesis of the being of one.

Followers of Parmenides worked themselves into logical knots and mystic raptures over the rather blatant contradiction between point five and everyday experience.

The philosophy of Parmenides is a strange blend of mysticism and logic. It is mysticism, for its goal is not the gradual and cumulative correction of empirical knowledge, but deliverance from it through the instantaneous and absolute grasp of "immovable" truth. This is not the way of techne, but the way of revelation: it lies "beyond the path of men" (B. 1.27). Yet this revelation is itself addressed to man's reason and must be judged by reason. Its core is pure logic: a rigorous venture in deductive thinking, the first of its kind in European thought. This kind of thinking could be used against the world of the senses … This projection of the logic of Being upon the alien world of Becoming was Parmenides' most important single contribution to the history of thought, though it is seldom recognized as such. Without it, his doctrine of Being could have remained a speculative curiosity. With it, he laid the foundations for the greatest achievement of the scientific imagination of Greece, the atomic hypothesis.

One of Parmenides' merits is to have been the first philosopher who strove to handle general concepts like "being", "not-being", "knowing", "unity", "identity", in their systematic connection.

Plato... says that Parmenides held "all things were one, and that the one remains at rest in itself, having no place in which to move."

Aristotle... [i]n the de Caelo... lays it down that Parmenides was driven to take up the position that the One was immovable... because no one... yet imagined... any reality other than sensible reality.

That which is, is ...it cannot be more or less. There is... as much of it in one place as in another... a continuous, indivisible plenum. From this it follows... that it must be immovable... [for] it must move into an empty space, and there is no empty space. ...For the same reason, it must be finite, and can have nothing beyond it. It is complete in itself, and has no need to stretch out indefinitely into an empty space that does not exist. ...It is equally real in every direction ...the ...the only form ...Any other would ...[have distinguishable] direction... [T]his sphere cannot ...move round its ...axis; for there is nothing outside ...[to] reference...

[http://faculty.washington.edu/smcohen/320/parm1.htm "Lecture Notes: Parmenides", S. Marc Cohen, University of Washington]

[https://plato.stanford.edu/entries/parmenides/ Parmenides] entry by John Palmer in the Stanford Encyclopedia of Philosophy

[http://philoctetes.free.fr/parmenides.htm Fragments of Parmenides] parallel Greek with links to Perseus, French, and English

[https://www.ellopos.net/elpenor/greek-texts/ancient-greece/parmenides-being.asp Parmenides Bilingual Anthology (in Greek and English, side by side)]

[http://parmenides.com/about_parmenides/ParmenidesPoem.html?page=12 Parallel text of three translations (two English, one German)]

A History of Western Philosophy#Chapter V. Parmenides

[H]e had been a Pythagorean ...and ...the poem is a renunciation of his former beliefs. ...The goddess tells him ...he must learn of those beliefs also "how men ought to have judged that the things which seem to them really are." ...He is to learn these beliefs "in order that no opinion of mortals may ever get the better of him" (fr. 8, 61). ...[T]he Pythagorean system ...was handed down by oral tradition ...Parmenides was founding a dissident school, and it was ...necessary ...to instruct ...disciples in the system ...to oppose. ...[T]hey could not reject it intelligently without a knowledge of it, and this Parmenides had to supply ...

Parmenides... tells us... that there is no truth at all in the theory which he expounds, and he gives it merely as the belief of "mortals." ...[T]he beliefs in question are called "the opinions of mortals" simply because the speaker is a goddess. ..Parmenides forbids two ways of research, and... the second... must be the system of Herakleitos. We should.... expect... the other way... is the... contemporary... Pythagorean [school]. ...[T]here are Pythagorean ideas in the Second Part of the poem ...Parmenides said ...there are really only two ways ...and that the attempt of Herakleitos to combine them was futile. ...[H]e ...put into hexameters a view which he believed to be false.

The... Neoplatonists... especially Simplicius... regarded the Way of Truth as an account of the intelligible world, and the Way of Opinion as a description of the sensible. ...[T]his is... an anachronism...

[T]he Peripatetic tradition was that Parmenides, in the Second Part of the poem, meant to give the belief of "the many." This is how Theophrastos put the matter... Alexander seems to have spoken of the cosmology as something... Parmenides... regarded as wholly false.

[Aristotle] was... aware that Parmenides did not admit the existence of "not being"... but... call[ed] the cosmology of the Second Part of the poem that of Parmenides. His Hearers would understand at once in what sense this was meant.

[T]he primary substance of which the early cosmologists were in search has now become a... "thing in itself." It never... lost this character again. ...[T]he elements of Empedokles, the... "homoeomeries" of Anaxagoras... the atoms of Leukippos and Demokritos, is just the Parmenidean "being." ...[A]ll materialism depends on his view of reality.

The appearances of multiplicity and motion, empty space and time, are illusions.

The path of speech (mythos odoio) (by Parmenides) contains within itself the path of day and that of night. It is no coincidence that Parmenides' poem comprises two parts. What exactly the second part contains and why it is so is an ancient philological and exegetical problem that we will not address here and which Plato already denounced in its ambiguity. In fact, it is not possible to separate being and speech without identifying them, and it is not possible to identify them without, ipso facto, separating them. The “simulation” (the simul) is immediate and structural. Human beings are simulators precisely because they are beings of truth. They cannot tell the truth without lying and vice versa. In this sense, they are beings of mediation, beings that stand in the middle, as you happily recall, that is, beings that ‘work’ to translate immediate experience into knowledge, or into a transferential process. God and nature do not work, but human beings do, first and foremost in naming the fruit of sexuality; it then places humans in the relational milieu of parents and children, brothers and sisters, offered, either really or symbolically, in sacrifice to God, that is, to the community of speakers. [...] The 20th century cannot exist without Sigmund Freud, psychoanalysis cannot exist without philosophy, at least in my opinion.

To prevent nothingness from being, Parmenides asserts that things are nothing. Parmenides, who first appears on the path of Day, which runs far from the path that the West has travelled, takes the first step along the path of Night in the West, the path along which things are thought and experienced as nothing. Parmenides is the tragic sower who sows both the seed of truth and the seed of Madness. (p. 77)

The history of the essence of nihilism (i.e., the belief that being is nothing) begins with Parmenides, who also affirms the eternity of Being and therefore the impossibility that it, in becoming, is not, i.e., is nothing. It is with Parmenides that the separation of beings from Being begins.

Parmenides believed that all Being is what he called the One, and denied absolutely the possibility of change. He believed that the cosmos is full (i.e., no void), uncreated, eternal, indestructible, unchangeable, immobile sphere of being, and all sensory evidence to the contrary is illusory. One Parmenidean fragment stated, "Either a thing is or it is not," meaning that creation and destruction is impossible.

The crisis at the heart of Parmenides' argument, "is or is not," rules out any candidate for an ultimate entity in an explanation of what there is that is subject to coming-to-be, passing-away, or alteration of any sort. Such an entity must be a whole, complete, unchanging unity: it must be a thing that is of a single kind … But it does not follow from this that there can be only one such entity. Parmenides' arguments allow for a plurality of fundamental, predicationally unified entities that can be used to explain the world reported by the senses.

The Greek tradition was a complete contrast to that of the Far East. ...the Greeks placed logic at the pinnacle of human thinking. Their sceptical attitude towards the wielding of 'non-being' as some sort of 'something' that could be subject to logical development was exemplified by Parmenides' influential arguments against the concept of empty space. ...He maintained that you can only speak about what is: what is not cannot be thought of, and what cannot be thought of cannot be. ...more unexpected was the further conclusion that time, motion nor change could exist either.

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.

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.

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.

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

From this inheritance contemporary philosophers have continued to draw profit. Parmenides is their earliest ancestor whose work contains explicit and self-conscious argumentation. The severe conceptual difficulties posed for the first time in his verses are of perennial interest, and many of them remain in the forefront of discussion today. Recent study has thus brought his thought, in the words of another critic, "astonishingly close to some contemporary preoccupations." He should be viewed not only as "the most original and important philosopher before Socrates" but as the first extant author deserving to be called a philosopher in a present-day sense of the word.

One cannot say that the case for Parmenides is proved. If it is accepted, it is a strange freak of history that so fundamental a discovery should have been made by one for whom the whole physical world was an unreal show.

The position of Parmenides is unique because it is also the point of greatest contact with the East.[...] Parmenides' radical solution is this: becoming no longer threatens, it cannot be harmful because it does not exist. [...] Everything that is distressing, terrible and horrendous in the world is illusion; this is the meaning of Parmenides' “'doxa”'. Well, this is also the path taken by the East: the “”Vedas“”, the “”Upanishads“”, the Buddhist revival of Brahmanism are all great themes that converge on this point: man is unhappy because he does not know he is happy, because he does not know that pain is outside him, and that he is a pure gaze that is not contaminated by the pain that passes before him, just as the mirror is not contaminated by the image reflected in it.

If I accede to Parmenides there is nothing left but the One; if I accede to Zeno, not even the One is left.

It was, for all I know, the first deductive theory of the world, the first deductive cosmology: One further step led to theoretical physics, and to the atomic theory.

Parmenides made it clear for the first time that the Immortal Principle, the One, Truth, God, is separate from appearance and from opinion, and the importance of this separation and its effect upon subsequent history cannot be overstated. It's here that the classic mind, for the first time, took leave of its romantic origins and said, "The Good and the True are not necessarily the same," and goes its separate way. Anaxagoras and Parmenides had a listener named Socrates who carried their ideas into full fruition.

As Parmenides categorically threw out all observation with the senses, so this student of philosophy is inclined to throw out Parmenides as a complete waste of time! His static theories denying motion and change were in direct antithesis to the Kinetic metaphysics of Heracleitus, and his depressing monism was later refuted by the atomists Democritus and Leucippus. In a nutshell; in a word; Parmenides is Pah! — and definitely not a philosopher to take to bed with you on a long winter evening! … Personally speaking the whole thing makes me shudder — although I do acknowledge that paradoxes and riddles are very popular with the average thirteen-year-old school boy. Zeno however, impressed his dialectical ability on Socrates, who then began turning it loose on the average citizen in the Agora (market-place) and in consequence made himself most unpopular. I only think that it is a pity that when they asked Socrates to drink the hemlock in 399 B.C., they didn' t include Zeno and Parmenides in the invitation.