The ancient philosopher Plato was born in Athens, Greece. Plato's beliefs and writings contributed much to organized study of ethics. Plato believed that all people in some way desired happiness. A person's actions do not always create happiness but this is because people do not know what their actions will produce. Happiness is a result of a healthy soul but moral virtue makes up the health of the soul. People do not always seek to be virtuous but this is because they do not realize that moral virtue produces happiness. However, Plato set forth that if a person knows that moral virtue leads to happiness, he or she should act acoording to this knowledge. Being moral or ethical, then, has its basis in knowledge or reason. If a person knows that virtue leads to happiness but acts contrary to this idea, he or she is immoral, and immoral behavior is the sign of a diseased soul.