Key Pre-Socratic Philosophers and Their Ideas
Unit 1: Pre-Socratic Philosophy
Pre-Socratic philosophy refers to the Greek philosophers who were active before Socrates, or contemporary thinkers who were not influenced by him. They are generally considered the first philosophers in the Western tradition. This period predates Socrates, who significantly shifted the focus of philosophy towards ethics and human knowledge.
These early thinkers primarily focused on cosmology, the nature of the universe (physis), and the fundamental substance or principle (arche) from which everything originates.
Thales of Miletus
Born in the city of Miletus (Ionia), Thales is often hailed as the first philosopher. No writings from him are retained; what is known comes from later philosophers like Aristotle who wrote about him. Observing nature, Thales proposed that water is the arche, the fundamental source of all things, likely noting its necessity for life.
Anaximander of Miletus
Also from Miletus, Anaximander lived during the 6th century BC. He reportedly wrote a book titled On Nature and created one of the first maps of the known world. Key ideas include:
- He defended the eternal movement and change inherent in the cosmos.
- He proposed the Apeiron (the “unlimited,” “boundless,” or “indefinite”) as the origin of all things. The Apeiron is an undefined, primordial substance from which specific, determinate things emerge and into which they return.
Anaximenes of Miletus
The third major figure of the Milesian school, Anaximenes proposed that air (aer) is the arche. He believed that changes in the world occur through the processes of condensation and rarefaction of air, leading to different forms of matter (e.g., wind, clouds, water, earth, stone). He likely drew this conclusion from observing the importance of breath for life.
Heraclitus of Ephesus
Born in Ephesus, Heraclitus is known for his cryptic pronouncements. His key ideas include:
- The origin or fundamental nature of things involves fire, representing constant change and transformation.
- He emphasized universal flux, famously stating “everything flows” (panta rhei). Reality is dynamic, like a river: “One cannot step into the same river twice.”
- He believed an underlying principle, perhaps termed Logos (Reason/Word/Order), governs this change.
- Harmony of Opposites: The world is a dynamic equilibrium of opposing tensions (e.g., life and death, waking and sleeping, young and old).
Pythagoras of Samos
Born around 570 BC in Samos, Pythagoras later established a school or community in Croton (Southern Italy). The Pythagoreans were known for:
- Their secretive practices and cultivation of various forms of knowledge, including mathematics, music, and astronomy.
- The belief that reality is fundamentally mathematical. They considered numbers to be the arche, the underlying principle of all things, resulting from harmonious numerical relationships.
- Significant contributions to mathematics and science.
Parmenides of Elea
Born in Elea (Paestum), Parmenides was an aristocrat and possibly a legislator. In stark contrast to Heraclitus, he argued:
- Change is an illusion. True reality (“What Is”) is one, eternal, indivisible, motionless, and unchanging.
- Sense perception is deceptive; only reason can grasp the true nature of Being.
- Thinking and Being are linked: One can only think of and speak of “What Is,” because “What Is Not” is unthinkable and unknowable.
- His ideas founded the Eleatic school and profoundly influenced metaphysics.
Empedocles of Acragas
Living from approximately 490 BC to 430 BC in Acragas (Agrigento), Empedocles was a philosopher, doctor, poet, and politician. His main contributions include:
- The theory of the four classical elements: He proposed that everything is composed of fire, air, water, and earth. These elements are eternal, but they mix and separate in different proportions to create the objects we see.
- The introduction of two cosmic forces: Love (Philia), which causes elements to combine, and Strife (Neikos), which causes them to separate. These forces drive the cycles of the cosmos.
Anaxagoras of Clazomenae
Born around 500 BC, Anaxagoras brought philosophy to Athens but was later banished for alleged impiety (perhaps for his astronomical claims, like the sun being a hot stone). Key concepts:
- He studied astronomy and natural phenomena.
- He stated: “Nothing comes into being or perishes, but is mixed and separated from existing things.”
- Mind (Nous): He proposed that initially, all things were mixed together in an infinitely divisible continuum. An external, ordering principle called Nous (Mind or Intellect) initiated motion and caused the separation and organization of matter into the cosmos we observe.
- “Everything in Everything”: He believed that in every object, there is a portion of every kind of thing (seeds or spermata), although one type may predominate.