Parmenides

b. 515? B.C.

Greek Philosopher

In a fragmentary poetic text, Parmenides outlined what he described as "The Way of Truth"—that is, the way of intellect, which penetrates the unchanging nature of true being—and "The Way of Opinion," or of the senses. Not only does this allegory represent one of the first attempts at philosophical discourse, but it had numerous (mostly unintended) implications for the development of scientific thought.

Born in Elea in southern Italy, Parmenides may have traveled to Athens in about 450 B.C.; this, at least, is the account provided by Socrates (470?-399 B.C.) in Plato's (427?-347 B.C.) Thaetetus. Aside from this detail, little else is known about his life, but from his philosophy—not to mention the fact that he came from an area where Pythagorean thought prevailed—it appears that he was heavily influenced by the ideas of Pythagoras (580?-500? B.C.) and his school.

What remains of Parmenides's thought can be found in two poems, "The Way of Truth" and "The Way of Opinion." Most of the latter has been lost, but a substantial part of the former still exists, including the stirring prologue in which Parmenides describes a journey "on the mystic way / That takes the man who knows through all the towns of men." Entering an ethereal bastion of truth through "the gates to the ways of Night and Day," he is greeted by an unnamed goddess who tells him, "No evil fate has sent thee on this way / (Though it lies far from travelled paths of men) / But divine will and justice. / It is fitting that you shall learn all things, / Both the constant heart of encircling Truth, / And also mortals' thoughts, where not one true belief lies. . . ."

What follows is a discussion of what Parmenides presents as the true nature of being: timeless, motionless, and changeless. According to Parmenides, nonbeing cannot exist, and this leads to a rejection of the principle put forth by Heraclitus (540?-480? B.C.) that being and nonbeing can exist simultaneously.

In order to assert that change is impossible, it is necessary to refute the validity of sense-impressions—which Parmenides seeks to do in "The Way of Opinion." To Parmenides, the physical objects of perception (though of course he would reject that very word) exist purely in the intellect, a position that helps explain his later appeal to Plato.

It is ironic that the man who went to such great pains to deny the existence of the physical world was in fact interested in a number of the sciences, most notably astronomy and biology. Parmenides's surviving work contains detailed descriptions of physical phenomena, a fact thathas long puzzled scholars, some of whom have suggested that he was in fact attempting to summarize existing thought patterns, or "The Way of Opinion."

Yet he went so far as to develop something that amounted to a form of cosmology, though the fragments of Parmenides's writing are too scanty to draw conclusions regarding its overall schema. Enough material does exist, however, to conclude that Parmenides was a discerning astronomical observer capable of insightful commentary on the subject. Also interesting, inasmuch as it marks another milestone toward the understanding of matter on the part of the ancients, was his theory that all physical substance (something of which he denied the existence!) is made up of Fire and Darkness, two opposing elements that appear in varying degrees within all forms of life.

By far the greatest impact Parmenides exerted on thought, however, lay in the combination of logic and mysticism that underlay his philosophical principles. Here was the first rigorous application of the logical method that would later be formalized by Aristotle (384-322 B.C.), and indeed Parmenides was the first to suggest something like the law of the excluded middle: that a thing cannot be both A and not-A at the same time.

And in his somewhat mystical attempt to prove that change does not exist, Parmenides perhaps inadvertently opened new paths of scientific investigation. Up to that point, practitioners of the new discipline of philosophy—Thales (625?-547? B.C.) was the first philosopher in the Western sense of critically approaching abstractions—had maintained that the entire universe consisted of one substance. Thales had called this water, Heraclitus fire. Parmenides had easily accepted the one-substance notion because it fit with his belief that change was impossible: if everything is one substance, then change really does not occur. Thus in order to maintain that change is possible, as scientists almost universally did, it became necessary to view the world in terms of multiple substances and elements.

Finally, Parmenides exerted an impact through his student Zeno, whose famous paradoxes examine the nature of space and motion and the continuity of reality. Like his teacher, Zeno in the end stumbled upon a set of questions greater than the answers he originally intended to offer.