Philosophers from the city of Miletus.

6th century BCE.
Considered himself to be a demigod, and founded a religion that among other things forbade eating beans, picking up something that had fallen, touching white roosters, stepping over a crossbeam, walking over main roads, et cetera.

In the community he founded, everyone was equal (women were also welcome), and there were no individual possessions. This included theorems and findings, making it hard to subscribe these to Pythagoras personally.

Said that "all things are numbers" and spoke of square numbers, cubic, long, et cetera. The Pythagoras theorem led to immeasurable numbers (e.g. decimals, root of 2), which led to the conclusion that calculation and measuring were to be practiced separate.

Sided with mysticism in the mysticism-rationalism opposition, although his was an intellectual mysticism.

6th-5th century BCE.
Considered fire to be the elementary substance as, like the flame, everything originated from the death of something else. Appeared misanthropic, and believed people could be pushed to act for their wellbeing only through violence.

Believed the soul to be a mixture of fire and water, where fire was the noble substance making people wise. Explained how "souls love to get wet", i.e. drunk.

Believed in eternal change ("panta rhei" likely apocryphal), and in the unity of opposing elements.

5th century BCE.
Hard to say whether much, or little is known about him as the authenticity of what is handed down (mostly by Plato) cannot be ascertained. Plato's Apology is generally considered to be historic: Socrates' oral defense in 399 during his trial for not recognising state gods and substituting his own, and in doing such, spoiling the youth. In reality, this trial was likely politically motivated as many of his pupils were from the aristocratic party.

In the Apology, Socrates explain that the Oracle of Delphi was once asked if a wiser man existed than Socrates, the reply to which had been negative. Socrates assumed it as his duty to prove the Oracle right. To this end, he met with people said to be wise, but concluded that they were not, and finally that only god is wise. The god would have wanted to demonstrate through the oracle's answer that human wisdom is worth nothing. This conviction did not bring Socrates many friends.

Dialectics appears to have first been methodically applied by Zeno, pupil of Parmenides, but it is reasonable to assume Socrates used and expanded this technique.

Plato was born in 428 or 427 BCE as a wealthy aristocrat. He was still young when Athens suffered its defeat, which he, as he had to in his position, blamed on democracy. He was a pupil and admirer of Socrates, whom democracy sentenced to death. He turned to Sparta for his views of an ideal society.

His main influences were from

• Pythagoras (religious tendency, belief in immortality),
• Parmenides (belief of an eternal and timeless reality, change is logically illusory),
• Heraclites ("panta rhei" in the world of the senses) and
• Socrates (preference for ethical questions, and for teleological rather than mechanical explanations).