Parmenidēs

Parmenidēs (c.515—after 450 BC), Greek philosopher from Elea (Lat. Velia) in south-west Italy, a Greek colony founded in 540 BC by Phocaea, the most northerly of the Ionian Greek cities in Asia Minor. He is said to have given laws to his city. According to tradition he was a pupil of, but did not follow, the Ionian philosopher Xenophanēs, preferring to associate with Pythagoreans. He is said to have visited Athens late in his life and to have met Socrates (see PLATO 2 for the dialogue Parmenides in which he is one of the chief interlocutors). He was the founder of the so-called Eleatic school of philosophy, and the first Greek philosopher whose doctrines survive fairly intact; they are found in a coherent series of quotations from the (lost) didactic poem in which he set out his thought. Written in hexameters, the poem consists of a prologue and two sections called the Way of Truth and the Way of Seeming.

The prologue opens with an allegory describing Parmenides' journey by chariot through the gate that leads from Night to Day, i.e. from false reasoning to true reasoning, the latter represented by a goddess who proceeds, in the Way of Truth, to tell the philosopher the truth of things as they really are. She begins by defining the two possible ways of enquiry, each contrary to the other: either a thing ‘is, and cannot not-be’; or it ‘is not, and must not-be’. The latter way is rejected on the grounds that it is impossible to conceive of the non-existent: one can only think or speak about ‘what is’. There is a third way which combines the two others: ordinary mortals, deluded by their sense perceptions, believe that a thing both is and is not (‘what is’ can become something different, i.e. what it hitherto was not, by means of change). This too is rejected, on the grounds that it is self-contradictory. Once the premiss ‘a thing is’ is established by elimination as the only possibility, Parmenides (in the person of the goddess) deduces all that follows from it: ‘what is’ is not subject to birth or decay; it is single and not divisible; it is complete in itself and unchanging. All of these conclusions are reached by reason alone, without appeal to the senses.

This section is followed by the Way of Seeming, in which the goddess, starting from an acceptance of the opposites light and darkness, builds up a cosmology which apparently represents the erroneous beliefs of men, based on the senses. Since Parmenides rejects these, believing only in the Way of Truth, and since in any case his cosmology had little apparent influence later, it hardly matters that the text of this part is too fragmentary to permit reconstruction. But in describing a self-consistent cosmology Parmenides seems here to be admitting the possibility of structure and pattern in the world of the senses. The mutually exclusive nature of the two Ways may indicate that Parmenides considered the world as explained by the senses and the world as explained by reason to be utterly different and unrelated constructions, only the latter representing reality. The interest of the Way of Seeming lies also in the incidental fact that Parmenides here implies, for the first time in Greek thought, the requirements of a scientific theory, that it should account for and correspond with all the observed phenomena, and should be coherent and systematic. The doctrines of Parmenides (and of his formidably brilliant disciple Zeno) offend against experience and common sense, but he was the most influential of the Presocratic philosophers; he had shown that even what men regard as fundamentally true was open to question. (For the answer of the atomists to Parmenides see DEMOCRITUS.)