Greece was famed for it philosophers, the most renowned being Socrates, Plato (Socrates' student, who established the Athenian school called The Academy), and Aristotle, who studied at The Academy.
Socrates developed the "Socratic method," a means of teaching that uses the question and answer method to lead a student to the correct answers.
It was Socrates' questioning of authority that led him to be condemned to death by an Athenian jury.
Plato's most famous work was The Republic. In it, Plate 'constructs' his ideal state. Plato is considered one of the greatest philosophers of western civilization and his works are studied to the present day.
Plato's student, Aristotle, wrote his treatise of government called ‘Politics’ In it, he divided governments into monarchies that could easily turn into tyrannies; aristocracies that could turn into oligarchies; and constitutional government that could become radical democracies.