"The natural is that which is everywhere, is equally valid, and depends not upon being or not being received...that which is natural is unchangeable, and has the same power everywhere.'
The Ancient Stoics emphasised the importance of Logos, or rationality, that governs the world and sees human nature as one natural order. They considered natural law as a law of 'right reason'. In his letter to the Romans, St Paul wrote about a law that is 'written in the hearts' of Gentiles. It is therefore clear that throughout the ancient world, although there is differing terminology, there seems to have been a consensus over the existence of a natural moral law, which dictated the rightness or wrongness of an action that was not dependent upon the laws created by society.
St. Thomas Aquinas developed a fuller account of this 'natural law' in the thirteenth century. This theory is both deontological and absolutist and so his resulting work is focused upon the ethicacy of actions. In his work 'Summa Theologica', Aquinas described natural law as a moral code, which exists within the purpose of nature and was created by God. He says that it is present in every human being. Natural Law exists to aid humans, directing their actions in such away that they might meet their eternal destiny. He argued that there was a basic law, from which all the other natural laws derived. This was to pursue good and avoid evil. For Aquinas, both the intention and the act are important, this is because his theory is based on a mainly deontological view. The only end that he values is God as He is intrinsically good. He believed that acts are intrinsically good or bad because when human beings act in accordance with their ultimate purpose, God is glorified.