Exploration of Knowledge - Thales (c.624 - c 546 BC)

Philosophy begins when human beings start trying to understand the World, not through religion or by accepting authority but through the use of Reason. This seems to have begun among the early Greeks in the 6th 5th, and 4th centuries BC.
The first philosophers were trying to understand the  world by the use of their reason , without appealing to religion, or revelation or authority or tradition. This was something new in the history of human civilisation. They were not used to communicate knowledge which they gathered but to ask pupils to discuss, argue, debate and put forward ideas of their own.

The first thinkers of this kind emerged in the ancient Greek world in the 6th century BC. Thales was a Greek who lived in the town of Miletus , onthe Asia minor coast of what is known Turkey. They were known  as Milesian School.He accurately predicted an eclipse of the sun in 585 BC.He was an Engineer and successfully diverted the course of the river Hylas. He thought that the world was created from a single element. Now it is proved that all the material objects are reducible to energy.He could see that water is converted to  rock at a very low temperature and air at a high temperature.
The current historical consensus is that Thales was born in the city of Miletus around the mid 620s BC. Miletus was an ancient Greek Ionian city on the western coast of Asia Minor (in what is today Aydin Province of Turkey), near the mouth of the Maeander River. The dates of Thales' life are not exactly known but are roughly established by a few datable events mentioned in the sources. According to Herodotus (and as determined by modern methods), Thales predicted the solar eclipse of May 28, 585 BC. Diogenes Laërtius quotes the chronicle of Apollodorus of Athens as saying that Thales died at the age of 78 during the 58th Olympiad (548–545 BC) and attributes his death to heat stroke while watching the games. Several anecdotes suggest that Thales was not solely a thinker but was also involved in business and politics. 

Thales was known for his innovative use of geometry. His understanding was theoretical as well as practical. For example, he said:

Megiston topos: hapanta gar chorei (Μέγιστον τόπος· ἄπαντα γὰρ χωρεῖ.)

“Space is the greatest thing, as it contains all things”

There are two theorems of Thales inelementary geometry, one known asThales’ theorem having to do with a triangle inscribed in a circle and having the circle's diameter as one leg, the other theorem being also called the intercept theorem. In 

"[Thales] is said to have been the first to have known and to have enunciated [the theorem] that the angles at the base of any isosceles triangle are equal, though in the more archaic manner he described the equal angles as similar.

Thales had a profound influence on other Greek thinkers and therefore on Western history. Some believe Anaximander was a pupil of Thales. Early sources report that one of Anaximander's more famous pupils, Pythagoras, visited Thales as a young man, and that Thales advised him to travel to Egypt to further his philosophical and mathematical studies.