Natalie Hill, age 15, of Boulder, Colo., for her question:

WHO WAS PLATO?

Plato was an educator and philosopher of ancient Greece. He is regarded as one of the most important thinkers and writers in the history of our Western culture.

Plato was born about 400 B.C. in Athens and was a member of one of the oldest and most distinguished families in the city.

When a group of wealthy citizens, including a cousin and uncle, established themselves as dictators in Athens, Plato was disgusted by their cruel and unethical practices. He left his home and traveled widely throughout the ancient world for a number of years.

When the Athenians deposed the dictators and established a democracy, Plato returned to Athens and founded a school of philosophy and science that became known as the Academy. The school stood in a grove of trees, according to legend, that was once owned by a Greek hero named Academus.

According to some scholars, the Academy is considered to have been the world's first university. Subjects taught included astronomy, biological sciences, mathematics and political science.

Plato's most distinguished pupil was the famous Greek philosopher Aristotle.

Plato wrote in a literary form called the dialogue. This is written as if it were a conversation between two or more people and the dialogues actually became dramas that were concerned with the presentation of philosophical problems, conflicts and ideas.

Many of Plato's dialogues try to identify the nature or essence of some philosphically important notion by defending it.

A complete edition of Plato's works includes 35 dialogues and a group of letters. Scholars today, however, agree that only about 30 of the dialogues and several of the letters were actually written by Plato.

Plato based his ethical theory on the proposition that all men desire happiness.

The basic problem of ethics for Plato is knowledge. If a man has the knowledge that moral virtue leads to happiness, Plato believed, he naturally acts virtuously.

Plato argued that it is worse to commit an injustice than to suffer one, because immoral behavior is the symptom of a diseased soul. He also believed that it is worse for a person who commits an injustice to go unpunished than to be punished, because punishment helps cure this most serious of all diseases.

Plato's political philosophy, like his ethics, was based on his theory of the human soul. He described the ideal state or society in a dialogue called "The Republic."

Plato also believed that the body would die and disintegrate, but the soul would continue to live forever; that after a time, the soul would reincarnate in another body and return to earth.