on his journey. They pass along the highway until they come to the Gate of Night and Day, which is locked and barred. The key is in the keeping of Dike, the Avenger, who is persuaded to unlock it by the Sunmaidens. They pass in through the gate and are now in the realms of Day. The goal of the journey is the palace of a goddess who welcomes Parmenides and instructs him in the two ways, that of Truth and the deceptive way of Belief or Seeming, in which there is no truth at all. It is clearly meant to indicate that Parmenides had been converted, that he had passed from error (night) to truth (day), and the Two Ways must represent his former error and the truth which is now revealed to him.
             In The Way of Truth , Parmenides explains his theory of what is real through the character of the goddess who knows all and can see the misperceptions of mortals. He points out that in all thinking we seem at first sight to be confronted with a choice: we can think about what 'is', or we can think about what 'is not'. But in fact, according to Parmenides, this choice is an illusion; we cannot think about what 'is not' because it is impossible to think about nothing. A person cannot think at all without thinking of something - something that exists as an object for thought. Parmenides expresses this idea by saying that thinking and 'being' are the 'same' in the sense that they are inseparable; you cannot have one without the other. He explains this idea with the words "you will not find thinking apart from what is" ; for a person thinks of what 'is'. The existence of something is the basis of all thinking, and because it 'is' (it exists), we cannot think its nonexistence; it not only 'is' but, as Parmenides puts it, "it is impossible for it not to be." He writes that "it is necessary to speak and to think what is; for being is, b...