Parmenides
He argued that reality is a single, unchanging, and eternal being, and that change is an illusion.
Most quoted
"The only roads of inquiry that are to be thought of: one, that it is and that it is impossible for it not to be, is the path of Persuasion (for she attends upon Truth); the other, that it is not and that it must not be, that I tell you is a path wholly unlearnable."
— from On Nature
"But since all things have been named light and night, and the names corresponding to their powers have been assigned to these things and to those, everything is full of light and obscure night together, of both equally, since neither has any share of nothing."
— from On Nature
"The only roads of enquiry there are to think of: one is that it is and cannot not be, this is the path of Persuasion (for she attends upon truth), the other, that it is not and needs must not be, this I tell you is a path wholly unknowable."
— from On Nature, -475
All quotes by Parmenides (130)
For it is necessary that being should be ungenerated and indestructible.
For it is not possible for what is not to be, and it is not possible for what is to be not.
For it is all one to me where I begin; for I shall come back there again.
The only roads of enquiry there are to think of: one is that it is and cannot not be, this is the path of Persuasion (for she attends upon truth), the other, that it is not and needs must not be, this I tell you is a path wholly unknowable.
For it is the same thing that can be thought and for the sake of which the thought exists.
What is, is ungenerated and deathless, whole and uniform, and still and perfect.
It was not nor will it be, since it is now all together, one and continuous.
To be and not to be are the same and not the same.
Mortals dwell in a state of illusion, naming two forms where there is but one.
Come now, hear my words, for I will speak of reliable truths.
Judge by reason the strife-filled refutation spoken by me.
Thinking and the thought that it is are the same; for without being, in which it is expressed, you will not find thinking.
It is necessary to say and to think that what is is; for it is to be, but nothing it is not.
The nature of all things that are is the same: changeless and eternal.
Do not let habit force you along this much-traveled way to lead astray your mind's eye.
Force the subjective view from your mind; do not let vast experience overwhelm you.
But extinguish your thought, and let the proof I offer compel you.
How could what is perish? How could it come into being?
Since it is now, all at once, it must either be completely or not at all.
The One is ungenerated and imperishable, whole, alone, shaken-free, without end.
Contemporaries of Parmenides
Other Philosophys born within 50 years of Parmenides (-515–-450).