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

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...

[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.