Eternal law is a concept that refers to the idea that there are certain moral principles that are universal and unchanging, and that they exist independently of human laws or beliefs. It is also known as natural law. Eternal law is the same as Gods perfect plan, which is not fully knowable to humans. According to St. Thomas Aquinas, eternal law is identical to the mind of God as seen by God himself. It determines the way things such as animals and planets behave and how people should behave. The eternal law is the highest conception or plan existing in God. It is the sovereign type, to which we must always conform. The eternal law is unchanging in its nature and rests in the mind of God. The key idea of the eternal law is that the law or the good, the thing that we ought to be aiming for the perfection of all things, rests in the mind of God. Now because God is eternal and unchanging, it also is eternal and unchanging.