Precursors
; This chapter focus on the ideas before Thales, and there are two main possible lines of
influences.
; The two possible lines of influences are:
； Native Greek antecedents
？ In Homer’s poems, there is an early conception of the nature and origins of the
universe. Such conception has echoes from the Pre-Socratic thoughts.
？ Hesiod had a poem concerning the origin of the universe.
； The other source is Egypt and Babylonian. There might be intellectual contact between
the Greeks and their eastern neighbors, but it is hard to find of single clear case of
influence.
Thales
; Thales of Miletus was the founder of natural philosophy. He observed the eclipse of the sun
on 28 May 585 BC.
; Knowledge about Thales depends entirely on later reports which are based on oral traditions. ; Thales is the man of practical wisdom.
; First, Thales held that the earth rests upon water as it can float
; Thales also held that everything was made from water, or that water was the material
principle of the world. Both according to Aristotle.
; Thales’ view on nature of the soul: soul produces motion and soul is mixed in the whole
universe.
; Geometric contribution: a circle is bisected by its diameter, about similar triangles, lines, and
other theorems.
; He was said to die when watching a gymnastic contest, the sun took his life.
Anaximander
; Anaximander was the pupil of Thales. He claims that the nature of limitless is the principle of
the things which exist.
; In biology, Anaximander said we came from fish-like animals that can take care of themselves
right after birth.
; His thought in astronomy: there is a circle 28 times as great as the earth and at the hub of
the celestial wheel is the stationary earth.
; His view on limitless: the things from which existing things come into being are also the
things into which they are destroyed. They give justice and reparation to one another for
their injustice in accordance with the ordering of time.