It is a happiness of following own nature and fulfilling own higher idea and purpose. The feature, commonly shared by all the people, according to Aristotle, is the reason. Ability to reasoning lies at the core of human beings. Rational capacities impose person’s capability to explore the world and support and focus own decisions and acts. Thomas Aquinas supposed that moral law is a part of the universal divine plan. There are innate tendencies of human nature that have to be enhanced and thus promote the greater good. He stressed the importance of liberty of knowledge and freedom of choice. There are some conflicting points regarding the moral law. For example, according to Darwin’s theory, poor and weak deserve their suffering as the natural law in evolution theory states that the strongest survive. Health care seems to be contradicting. All the people have both people and animal natures. This means all the people contain some degree of aggression for survival. Thus, there are joint collective values for common good and survival, while other aspects may involve competitiveness, destructive features, etc. All the living creatures and systems are aimed to develop. It is seen through all the species. Systems and creatures evolve and become more complex. Eudaimonia means revealing and fulfilling own concept. Finding own role, in which a person may both achieve own happiness and promote the greater good for the maximum quantity of people is probably a natural law, which is imprinted into the human nature.