Legal jurisprudence: The theory of natural law According to the ancient Greeks, the universe is governed by reason or rational principle and all human beings have reason within themselves and can therefore know it and obey it law. Since humans have free will, they will not necessarily obey the law if they act according to reason, however they will follow their nature (Halley). Therefore natural law can be defined as the unwritten law which is almost the same for every human being everywhere. It is the concept of a set of moral principles common to all humanity and recognized only by human reason. Therefore natural law provides the standards for the positive law of a particular society. Aristotle's Natural Law Theory: The Aristotelian view of natural law theory is to reject subjectivism regarding the good by holding that it is somehow perfective or completion of a being where the perfective or completion of a being depends on the nature of a person. So, according to this view, what is good for a tree is what is perfective or completionist of the tree depends on the nature of the tree and what is good for humans is what is complete or perfective for the man depending on the nature of the human being. Thus the fact of the variability of desire is not sufficient to raise questions about universal goods, since the good is not fundamentally defined by reference to desire. Cicero's Natural Law Theory The Stoic philosophers constructed a universal system based on the concept that all men have the gift of reason and that law is right reason applied to the regulation of human behavior. Cicero in the Republic had presented the best-known formulation of this concept. He said: “True law is right reason in accordance with nature; is of universal application, immutable and... middle of paper... that promises must be kept, which in turn is the basis of contract law (Murphy) Trust: the obligation of trust is the fundamental condition of social harmony. Duties of loyalty derive from natural law principles and reflect the institutionalization of trust that is essential for the survival of human association. Bottom line: The United States is a republic based on the rule of law. The rights of personal liberty are better protected here than in any other country in the world. But unfortunately the law becomes more and more complex and it is not easy for ordinary people to set their conduct according to the law. Intellectual and legal history moves in cycles and it is much better for the nation and the country to reverse the cycles of ideas towards first principles. It gives us the opportunity to restore the essential framework for the rule of law.