PAR 201: History of Ancient and Medieval Philosophy

Dr. Schmid at Delphi, 2010

PRESOCRATIC PHILOSOPHERS600-400 B.C.E.

The Presocratic Revolution

World of myth (mythos)• Divinely inspired poets reveal truth in stories

(Homer, Hesiod)• World = governed by divine agents (Zeus, Hera, etc.)

World of science and philosophy (logos)• Scientists argue for universal laws based on

evidence, reasoning • World = governed by laws of nature

Three Milesians = Natural Scientists & Philosophers of Nature

1.Thales 600 BCE

2.Anaximander 570 BCE

3.Anaximenes 540 BCE

Two principles of naturalism • Methodological naturalism =

all knowledge of the universe is based on observation and reasoning from natural, empirical sources alone

• Metaphysical naturalism =

everything that exists derives from a common ground of natural substance, the world is one material whole

Thales (~600 BCE)

Thales’ Four Quotes: are these consistent with ‘naturalism’?

1.The earth rests on water. 2.Water is the arche (principle,

origin, source) of all things 3.The magnet has a soul. 4.All things are full of gods.

Anaximander (~570)= 1st scientific

philosopher of nature

5 Principles of Naturalism

1.Underlying substance

2.Causality

3.Evolving Universe

4.Mathematical Form

5.Unifying Law

1. Metaphysical Materialism

The first principle and origin of being is neither water nor any of the other things called elements, but some other nature which is unlimited [apeiron], out of which come to be all the heavens and the things in them.

2. Causality

• a kind of sphere of flame … was broken off and enclosed in circles, the sun, moon, and stars came to be. . . their protective covers broke off, and they lived a different sort of life. . . The things that are perish into the things out of which they come to be, according to necessity . . .

3. Evolving Universe Heavens and Earth

• What arose from the eternal [apeiron] and is productive of hot and cold was separated off at the coming to be of this kosmos, and a sphere of flame from this grew around the dark mist about the earth like a bark about a tree. When it was broken off and enclosed in certain circles, the sun, moon, and stars came to be.

Life and Humankind

• The first animals were produced in moisture. When these water-creatures came out onto the land, their protective covers broke off, and they lived a different sort of life. The first humans arose from fish or fish-like creatures.

4. Mathematical Form

The earth is round and cylindrical, three times as long as in diameter. The circle of the sun is 27 times that of the earth, the moon 18 times that of the sun.

5. Unifying Law(compare Zeus)

The things that are perish into the things out of which they came to be, according to necessity, for they pay penalty and retribution to each other for their injustice in accordance to the ordering of time.

Anaximenes (~540)

New concept of ‘substance’

The form of air is the following: when dissolved into what is finer, it becomes fire, winds when then condensed. Cloud results from air when it becomes denser, and water when this happens to a greater degree. Condensed still more, it becomes earth; at the densest stage, stones.

Cause of Lightning

• Lightning is the flash of fire caused when the heavy air particles of two clouds rub quickly together, and make a spark…

Goodbye,

Zeus

Impact of discovery of nature

• What will be the impact of “natural science” on ancient culture?

– Religion?

– Ethics and Politics?

– Art?

– Experience of nature and the world?

– Human self-understanding?

Milesian World-View: Do you agree?

1. Everything that exists is physical

2. The laws of nature are regularities discovered in sense-experience

3. The universe and its laws evolved and may change

4. Humans are mortal animals that also evolved

5. Human culture and norms derive from nature or human construction