Foundational Ideas of Early Greek Philosophy

Thales of Miletus

Little remains of Thales's original writings, but his views are widely referenced. He theorized that water is the fundamental principle of all things. He also believed the Earth was motionless, floating on water.

Anaximander of Miletus

Anaximander followed a similar philosophical path, interpreting the relationship between humanity and the cosmos. He introduced the concept of Apeiron (the boundless or indefinite) as the fundamental principle of existence, containing the cause of birth and destruction throughout the world.

Anaximenes of Miletus

Also from Miletus, Anaximenes proposed air as the foundational element of all things. He theorized that the varying densities of air, through condensation and rarefaction, give rise to the diverse phenomena observed in reality.

Heraclitus of Ephesus

Born in Ephesus, Heraclitus's philosophy centered on change and the unity of opposites.

The Hidden Fire and the Soul

Fire, for Heraclitus, symbolized the ever-changing and unstable nature of reality, encompassing both its ascent and descent. He saw it as the primary element and a metaphor for the soul's dynamic nature.

The River of Change

Heraclitus's most famous metaphor for the continuous flux of existence is the river, which one can never step into twice. This concept of incessant change was condensed into profound philosophical statements, emphasizing that "everything flows."

The Harmony of Opposites

Heraclitus argued that apparent contradictions and oppositions are fundamental to the underlying unity of reality. For instance, life and death, youth and age, are intertwined. Fire, which transforms all matter, serves as a prime example of this divine unity.

Logos

A concept rich in nuance, Logos represents the universal reason that unifies all things. Heraclitus believed that many people fail to comprehend this fundamental principle, which governs the cosmos and human understanding.

Pythagoras of Samos

Pythagoras, whose influence on philosophy and mathematics was profound, founded a school of thought that deeply impacted Western intellectual tradition.

The Soul and the World

Pythagoras believed in the immortality of the soul and its transmigration into other species. He also posited that events repeat periodically. The Pythagoreans believed that the soul, akin to dust in the air, enters a baby through breath.

Number and Harmony of the Spheres

Pythagoras's perspective on the cosmos, particularly the "harmony of the spheres," gradually approached what we now recognize as scientific knowledge, a concept also transmitted through Aristotle's writings in On the Heavens. He emphasized the fundamental nature of numbers as the essence of reality. Pythagorean mathematical contributions include the famous Pythagorean theorem, the discovery of the incommensurability of the diagonal and side of a square, and various numerical distributions, oppositions, and geometric relations.