The one generalization from experience that all of the sixth century philosophers agreed on unconditionally was that everything that we experience in this world is constantly changing. But this is derived entirely from experience. It is not rationally derived through reason. At the same time all of the reasoning of these thinkers was based on this one generalization. By the fifth century a Pythagorean from Elea in the south of Italy changed the entire face of western philosophy and science by showing that it is a logical absurdity to consider that any kind of change at all is possible. His name was Parmenides and we can get a good idea of his position in the succession of philosophers because Plato, in a dialogue named after him had Socrates as a young man meeting Parmenides who is depicted as an old man. The deference that Plato showed to the old man in the discussion indicates how highly he thought of him. As I mentioned before he was a Pythagorean, but broke away from the sect to found his own school.

He communicated his ideas through the most powerful medium he knew, epic poetry. His basic concept was that not only is change impossible, but that the existence of many things is equally absurd, was put forward in an epic poem in which a goddess shows him two paths, that of truth, and that of the opinions of mortals. Only through the expressive language of verse could he overcome the difficulty of putting forward very complex philosophical concepts in a language that simply did not contain expressions capable of conveying them.

The object of Parmenedes' search was truth through reasoning. Of all of the problems of philosophy truth is the most elusive because reasoning to be of any value must begin with truth. It cannot create truth. He chose to follow a path toward truth concerning being itself. First, there are only two kinds of being. That which is, and that which is not; for being is a binary conception, something either is, or it is not. But what of what is not? To speak of what is not is an absurdity, for to speak of it is to imply that it is. Therefore he began his argument from the basic fact that one simply cannot speak of what is not. What is wholly true, then, is that which is, and what is not cannot even be talked about. Let us consider the rational implications hidden in those simple statements.

What is could never be derived from what is not. That would be absurd. Therefore what is could never have not been.

What is, too, could never become what is not, so what is can never not be in the future.

If what is were many then each of the many would necessarily be separated by what is not. But what is not can never be, therefore what is cannot possibly be many.

Motion is impossible because it necessitates that what is either has not been or will not be, either of which is impossible.

Remember, what makes a philosopher important is not that he changed the world around him. The world around him is changing. He becomes important because through reason, he has captured the thought that lay deepest in the minds of the people of his culture. in a sense he recreates the change that is happening around him so that he creates a feed-back path that locks the change in or accelerates it. He becomes important to us not because he changed the people of his time, but because he was important to them. He was important to them because he was able to express what they felt but could not express themselves. Parmenides was not speaking to future philosophers and philosophy students. He was speaking to the citizens of Elea and he could accomplish this best through his epic poetry.

In the beginning the poem which is speaking to Parmenides, purports to explain the truth about reality from premises asserted to be wholly true. This leads to the conclusion that the world as perceived by the senses is unreal. At this point the goddess declares that she ceases to speak the truth, that the remainder of the poem will be deceitful, yet she will impart it all to Parmenides 'that no judgment of men will outstrip thee'. The following translation of the prologue to the poem is taken from W.K.C. Guthrie.

The mares that carry me as far as my heart ever aspires sped me on, when they had brought and set me on that far famed road of the god [i.e. the sun], which bears the man of knowledge over all cities. On that road I was borne, driven on both sides by the two whirling wheels, as the daughters of the sun, having left the house of the night, hastened to bring me to the light, throwing back the veils from their heads with their hands.

In the Persian religion of the day, there were two Gods. One, Ahura Mazda the God of light, was all good. the other, Ahriman the God of darkness was all evil. In this poem Parmenides used this motif with the Greek idea that connects darkness with ignorance and light with knowledge. So, in this poem night and darkness symbolize ignorance while light signifies knowledge. The sun as that which illuminates all that is visible brings knowledge to man. Parmenides is shown as a privileged mortal who is to be shown both the truth and that which the ordinary mortal takes for truth.

These are the gates of night and day, set between a lintel and a threshold of stone. They themselves, high in the sky, are blocked with great doors, of which avenging justice holds the alternate keys. her the maidens beguiled with soft words, and skillfully and persuaded her to push back swiftly for them the bolted bar from the gates. The doors flew back and revealed the wide opening between their leaves, swinging in their sockets the bronze-bound pivots made fast with dowels and rivets. Straight through them the maidens kept the chariot and horses on the highway.

And the goddess welcomed me graciously, took my right hand in hers, and addressed me with these words:

Young man who comest to my house companioned with immortal charioteers with the steeds that bear thee, I greet thee. No evil lot has sent thee to travel this road--and verily it is far from the footsteps of men--but Right and Justice. It is meet for thee to learn all things, both the unshaken heart of well-rounded truth and also what seems to mortals, in which is no true conviction. Nevertheless these things too shalt though learn, namely what seems had assuredly to exist, being indeed everything.

The meaning of the prologue is quite clear. Parmenides is privileged above other mortals. He is borne through the sky in the sun-chariot driven by the sun's daughters. It is a journey from night to day, from ignorance to truth. Where these meet is a gate guarded by the figure of justice and none may pass without her permission, that is unless his passage is sanctioned by divine consent. Once through the gate the road leads to the house of an unnamed goddess who confirms his right to be there and promises to teach him all things, both the truth and what is falsely believed by mortals. How much of this is the typical Greek prayer to the muses and how much is a sign of divine revelation is impossible to determine from this distance in time. However, there are other similar journeys portrayed in Greek literature, particularly in orphic doctrine. It is of some note that this poem was written in the south of Italy where mystical religion was at home, and by an ex-Pythagorean. But let us look at more of the poem.

Come now, I will tell (and do thou lay up my word when thou hast heard it) the only ways of inquiry that are to be thought of. The one, that it is and that it is impossible for it not to be, is the path of persuasion (for she attends on truth). the other, that is not, and that it must necessarily not be, that I declare is a wholly indiscernible track; for thou couldst not know what is notthat is impossiblenor declare it, for it is the same thing that can be thought and can be.

This passage has been discussed over and over again by scholars. It contains the germ of Parmenides concept of the one. As you may recall from when we discussed the Milesians, they proposed that the universe began as a single substance and all that exists now emerged out of that substance through the effect of eternal motion. In the passage above Parmenides identified what is and what can be talked about or thought about as being identical. He went on to say that what is can never not be or can never not have been. What is, he said must be everlasting, indivisible, and motionless. These statements seem incompatible to our twentieth century mind. But for the Greeks the power of cognition occurs when a person realizes the full extent of a situation. Therefore, to know or think that something is, is to know that it cannot not be for knowledge is of things that can not be other than they are. Therefore there is no possibility of speaking of what is not, for one would be speaking of nothing and that is nonsense. At the same time we can see that if what is could never be other than it is, then motion is impossible. Motion implies that what is, is derived from what is not, and what is not is nothing. That, of course, is not possible. Reality cannot be many either. For there to be more than one there would have to be something which separated them and this would have to not be, which is absurd. Also, if there can be no coming to be then reality can not be many therefore it is by necessity one. All reality, then, becomes Xenophanes' One God. Only this return is one through pure reasoning. Perhaps more of the poem will help to clear some confusion on this topic.

What can be spoken and thought of must be, for it is possible for it to be, but impossible for nothing to be. This I bid thee consider, for this way of inquiry is the first from which I hold thee back. But also from this one, on which mortals, knowing nothing, wander two-headed; for helplessness in their own breasts guides their erring mind. They are borne along, both deaf and blind, mazed hordes with no judgment, who believe that to be and not to be are the same and not the same, and the path of everything is one that turns back on itself.

For this shall never prevail, that things that are not are, but do thou keep thy thought from this way of inquiry; and let not habit born of much experience force thee along this way, to ply a heedless eye and sounding ear and a tongue, but judge by reason the much-contested refutation spoken by me.

In the first passage Parmenides is arguing that the object of speech and thought must exist simply because it can exist. In other words it cannot be nothing because nothing cannot exist. Therefore the first error to be avoided is thinking that `nothing' can exist. If something exists then the word is must be applied to it and therefore it cannot ever not be and it can never not have been. The problem with ordinary mortals is that they haphazardly confuse the words is and is not. This, of course, is not a conclusive proof that there is no possibility of motion or of many things. However, it poses an interesting philosophical problem. That is, if we reject the world of the senses, which we must if we are to accept that there is any validity at all in either the Hericlitean or the Parmenidean view of reality, then how can we talk about the sensible things with which we interact in our normal lives?

The thrust of presocratic philosophy prior to Parmenides was that what can be known is the unchangeable that lies behind the changing world of the senses. But this can only be known through the mind acting with the power of reasoning. The changing world of things can never be known but the unchanging world of the mind, that is a source of eternal and divine knowledge. But Parmenides has shown that reasoning itself can lead to contradictions. That the eternal world of the mind itself leads to a singularity. In a sense his thought leads to a conclusion that is remarkable similar to that of Hericlitus who said that the only reality is change itself. But neither of these turned out to mean the end of philosophy, they simply posed new challenges to philosophers. Although the Eleatic conclusions might seem outlandish if not completely absurd to our modern ways of thinking, as a matter of fact it is very much in line with Einstein's conception of a four dimensional block universe.

Again I must remind you that the importance of a philosopher is not the great ideas that he spawns, but that what he expresses resonates in the thoughts of the people of his time. That the world we live in is an illusion and that behind that illusion lies an ineffable truth expressed very well the thought of the fifth century and led to the great breakthroughs of the fourth.