One of the key disputes that divided ancient Greek philosophers was the question of the elements. Some philosophers, such as Thales (620–546 BC), believed that water was the fundamental substance of the universe. Others, led by Anaximenes (585–525 BC), argued for air.

As for Heraclitus (c. 540–c. 480 BC), a wealthy aristocrat from the city of Ephesus whose writings burned with hostility toward his fellow citizens, he held with fire. Heraclitus posited that fire was the basic building block of nature from which all other substances were derived.

Little is known about the life of Heraclitus. But the surviving fragments of his works show a deep contempt for other Greeks, and especially for his neighbors in Ephesus, a prosperous city on the coast of present-day Turkey. (In one text, he recommended that the citizens “would do well to hang themselves, every grown man of them.”)

Heraclitus believed that the dispute over the makeup of the universe carried important philosophical implications. Because the world was made up of fire, Heraclitus theorized, it was constantly changing. This idea—that the world was in constant flux—was one of the most important tenets in his philosophy.

The world, he wrote, “is now, and ever shall be an ever living Fire, with measures kindling and measures going out.”Amid the constant transformation, Heraclitus wrote, there were few constants—an idea that put him in opposition to other Greek philosophers who sought to define eternal truths. Because he believed that change was inevitable and constant, he argued that people could not be trusted to manage their own lives and should be forcibly led in the right direction by authoritarian measures. “Asses would rather have straw than gold” and needed to be prodded to act in their own best interests, he wrote.

After spending his last years eating herbs and grass and avoiding human contact, Heraclitus died at about age sixty. But his writings continued to challenge later philosophers, including Plato (c. 429–347 BC), who tried to disprove some of Heraclitus’s theories. As for the elements, the Greeks eventually concluded that the universe was made up of four elements—earth, air, fire, and water. This view would prevail for centuries, until the development of modern chemistry.


  1. Ephesus was the home of the Temple of Artemis, one of the Seven Wonders of the Ancient World, which was completed in roughly 550 BC. The city is now known as Efes, Turkey.
  2. The philosopher is sometimes known as Heraclitus the Obscure because of the supposed difficulty of his writing style.
  3. Heraclitus was a critic of the ancient Greek poet Homer, once writing that Homer should have been beaten for writing The Odyssey and The Iliad.

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