What other accomplishments are attributed to Thales?
Thales visited Mesopotamia and Egypt and studied astronomy. He predicted the solar eclipse during a battle between the Lydeans and the Persians in 585 b.c.e. (A legend has it that he changed the course of the Halys River so that King croesus could cross it). He is said to have been able to measure the height of the pyramids and distances at sea. His practical studies in engineering may have resulted in his creation of axioms, or abstract first principles, of the field of geometry. Thales was highly regarded for his wisdom.
How did Anaximander seek to revise Thales' philosophy?
Anaximander (c. 610—545 b.c.e.) was interested in the idea of what was hot and dry; this was supposed by him to be opposed to Thales' idea of water, which was cold and wet. He reasoned that water could not be the primary substance out of which everything else was made because the primary substance must be the cause of all the others. Since water is wet and often cold, it cannot be the source of anything that is hot and dry. Therefore, Anaximander reasoned, the primary substance must be something different from both water and things that are hot and dry.
Anaximander called his primary substance, which cannot be perceived—only things that are cold and wet or hot and dry can be perceived—apeiron, or that which is eternal and causes other things to change, but does not change itself. Apeiron, in other words, is that thing which can't be perceived itself but which is the origin of all things hot and cold, wet and dry, and for how these things change—it is responsible for everything in the world as we can and do perceive it.
According to Anaximander, we see the Sun, Moon, and stars through holes in a cold, wet vapor that encloses Earth. On Earth, wet and dry have formed land and sea, and living things are the result of the Sun's effect on moisture. All life started in the sea, according to Anaximander, a theory that actually anticipates the theory of evolution.
How did Anaximenes revise the theories of Anaximander?
Anaximenes (c. 580-500 b.c.e.), who followed Anaximander in the Ionian school founded by Thales, believed that the primary substance of the universe was air. Air could itself change from hot to cold and back, so with air as the primary substance it was no longer necessary to explain how the primary substance caused the separate perceptible substances. Air could either expand or contract: expanded air became fire; contracted air became the denser materials of wind, cloud, water, earth, and stone. In many religious traditions, including Hindu yoga, life itself is breath. The ancient Greeks strongly held this association, going back to the eighth century b.c.e., but Anaximenes was the first to give it formal expression.
Why was Pythagoras important?
Pythagoras (c. 570-495 b.c.e.) is credited with inventing the word "Philosophia." He was born in Samos but settled in croton, where he founded a brotherhood that was a school, a way of life, and a set of religious and political beliefs. Pythagoras discovered that the musical interval marked by the four fixed strings on seven-string lyres could be explained by ratios of the numbers 1, 2, 3, and 4. This was an important realization that forms the basis of the concept of harmony in
Most people think of Pythagoras in terms of his contributions to mathematics, but few realize that his work has also been important to philosophy (iStock).
Heraclitus thought that the essence of life was an inconclusive battle of opposites (Art Archive)
music. Pythagoras went on to explain how number systems correspond to natural phenomena such as the movement of celestial bodies. Pythagoras' insight about mathematics is relevant today, because mathematics is the language of modern physics.
Pythagoras and his followers also had a great interest in numerology and theories of the mystical significance of numbers. They embraced music as the spiritual side of number and believed that the right practices—in daily habits and diet, as well as playing musical instruments— could enable them to hear the music of the stars and planets. They were strict vegetarians, except for a prohibition against eating fava beans.