When he returned to Athens in 387 before Christ, he founded an academy in a garden outside the gates of the city, where he taught for 40 years until his death in 347 before Christ. It was here that he wrote his philosophical treatises on the ideal state.
Plato comes to the realization that a society can only function if there are clear boundaries between rulers and controlled ones. The community must be governed by an elite that does justice to this term and that does not abuse its power, as the 30 tyrants or Dionysios did in politics. In his most famous writing about the state he explains his ideas.
For Plato, man is first and foremost a being of rationality, which is why reason must take precedence over one's own will and passion in all decisions. A just order is established when rationality dominates passion with the help of will.
Applied to the ideal state, this means for Plato that justice is achieved when rationality in the state structure of the rulers is achieved with the help of the servants who represent the will, who rule passion, thus the people. According to this conception, the ruler is characterized by wisdom. He makes all important decisions and communicates them to his servants. These are particularly brave and assert the ruler's decisions inwardly and outwardly. The people must be prudent, for they must suppress their own needs and subordinate themselves. As long as everyone keeps to his duties, there can be no unrest or revolt.
However, this system can only function if the rulers are educated and wise. They must therefore be given a special education, because only if it can be prevented that the ruler can exploit his supremacy, i.e. justice can be guaranteed. The lifestyle of the rulers must therefore be ascetic and disciplined.
Sexual intercourse may only take place in order to show the best offspring for the state. This offspring is prepared for its later task from childhood on. Only after a comprehensive education, which among other things includes a five-year philosophy course, can the new ruler be found among the offspring. However, he must be at least 50 years old so that he has enough experience to govern a state fairly.
When Plato dies at the age of 80, he leaves behind a multitude of philosophical writings, including about 25 dialogues, which among other things provide a great insight into the thinking of Socrates.
To this day, Plato's life's work is regarded as formative for the subsequent philosophical teachers. Up to our century Plato's ideas have always found supporters, especially dictatorial rulers like to take parts of Plato's political work as legitimation for their actions. However, in this context they mostly neglect the aspect of justice...