The Parmenidean Paradox of Motion

Philosophical thought begins with the Milesians, where intellectual curiosity propelled thinkers like Anaximander and Heraclitus to attempt to explain the phenomena of the universe by means of specific physical elements. During the 6th century BC, Eleatics, like Parmenides and Zeno, had rejected physical phenomena and propounded metaphysical paradoxes that cut at the roots of belief in the very existence of the natural world. Parmenides uproots the theories of his predecessors by bearing to light the logical possibilities of any philosophical inquiry. He argues that that the only things about which we can inquire about must exist, else our search is fruitless. Through deductive reasoning, Parmenides proves that if something exists, then it cannot come to be or perish, change or move, nor be the subject to any imperfection. His proteges were left with an enormous problem: how could one reconcile Parmenides' rejection of change with the possibility of giving a rational account of the changing world of sense experience? By accepting only certain parts of his doctrine of being, his successors ultimately fail in their attempts to explain the changing universe in light of the Parmenidean paradox.

How does Parmenides draw the conclusion that if something is, then it is unchanging? A more formal examination of his arguments regarding subjects of inquiry shows how he comes to the conclusion that all is one. The only ways of inquiry there are for thinking: the one, that it is and that it is not possible for it not to be, is the path of Persuasion (for it attends upon the Truth), the other, that it is not and that it is necessary for it not to be, this I point out to you to be a path completely unlearnable, for neither may you know that which is not (for it is not to be accomplished) nor may you declare it (Curd fr.2 ll.3-8, pg.45).

Parmenides' subject of inquiry, as show in the fragment, either you must assume that your subject is or it is not. Careful consideration of the statement Ð''is not' shows that it is impossible to point out what does not exist, because it has no attributes or true predicate. Parmenides concludes that if something does not exist, then its non-existence cannot allow for it to come into being or perishing, because if it comes to be, then formally, it previously did not exist. Since we cannot know anything about things that do not exist, coming-into-being cannot be logically explained because it involves something that previously did not exist.

Parmenides' entire concept of being rests upon this foundation that rules out the possibility of non-existence. A being must be one and continuous, eternal, for it has no beginning and has no end. Furthermore, he rules out combination and change because these things disrupt the continuous perfect order of the universe. Therefore, Parmenides rejects motion because being "remains the same in the same and by itself it lies and so stays there fixed" (Curd fr.8 ll.29-30, pg. 48), and as such, if a being would move then it would not remain the same.

His predecessors, the Pluralists Anaxagoras and Empedocles, respond to the Parmenidean problem of being by asserting that the basic substances, which make up the universe, are entities that have features genuine to the idea of being that he argues for. These entities are eternally real and unchanging, but at the same time they can be mixed and separated from each other. Anaxagoras imagines the original state of the cosmos in terms of eternal substances that have not been separated from one another. A divine Nous or mind sets this original mixture into motion, from which everything is separated. Anaxagoras tries to reconcile the Parmenidean idea of unity by stating that "in everything there is a portion of everything" (Curd fr.12 ll.1, pg.56), but his originative substance, although it is eternal, it still sets about motion and change, and does not remain a substantive whole that Parmenides imagined. Furthermore, the original state remains whole only until Nous separates it into a plurality of parts.

Empedocles, like Anaxagoras, wants to describe the universe in terms of particular elements, and he names them Earth, Air, Fire, Water, Love, and Strife. The action of Love and Strife upon the other four elements brings about their mixture and separation. This resembles coming-into-being and passing away, but Empedocles explains it in a twofold tale.

For at one time they grow to be only one out