Natural Law Tradition in Legal Theory

Article in  Wikipedia, Sanford Encyclopedia of Philosophy,  Internet Encyclopedia of Philosophy

Article - Philosophy of Natural Rights 


Natural law theory in application:

Natural law theory has various applications.  In the 17th century, natural law was used to challenge the divine right of kings and in the development of international law to maintain peace among the rising nation-states of Europe, especially in Just War theory, a tradition of national military ethical thought that set out when it was ethical (just) for a country to go to war and what is ethical fighting during a war. 

In the 18th century, the idea of natural law theory would be used to establish positive law.  Also in the 18th century, natural law would give rise to the idea of natural rights: 

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.

In the 20th century Mohandas Gandhi and Martin Luther King, Jr. appealed to natural law in claiming some positive laws of Great Britain and the United States were unjust.


What is natural law?:

Natural law (Latin: ius naturale, lex naturalis) is a philosophy asserting that certain rights are inherent by virtue of human nature endowed by nature; traditionally God or a transcendent source, and can be understood universally through human reason.  As determined by nature, the law of nature is implied to be universal, existing independently of the positive law of a given state, political order, legislature or society at large.  Historically, natural law refers to the use of reason to analyze human nature to deduce binding rules of moral behavior from nature's (or God's) creation of reality and mankind.   

It featured greatly in the works of Alberico Gentili, Francisco Suárez, Richard Hooker, Thomas Hobbes, Hugo Grotius, Samuel von Pufendorf, Matthew Hale, John Locke, Francis Hutcheson, Jean Jacques Burlamaqui, Jean Jacques Rousseau, Emmerich de Vattel, and Cesare Beccaria. 

The natural law tradition in legal theory sharply contrasts with legal positivism which holds that law is not dependent on an objective moral world  but on real world social factors. 

David Hume, the 18th century philosopher, would denounce the idea of natural law. 


History of natural law through the 17th century:

Aristotle on Natural Law

     Aristotle divided laws up into two categories:

         Natural Law (Universal law) - which all apply to all men - Natural rights 
         Customary Law - Laws of the customs of a particular group of people

          Natural Law trumps customary law - 

             Whether Aristotle believed natural law actually existed, or was just a rhetorical appeal of injustice of a customary law is disputed. 


Natural law in Medieval Scholasticism (Aquinas on natural law):

"Every human law has just so much of the nature of law as is derived from the law of nature.  But if in any point it deflects from the law of nature, it is no longer a law but a perversion of law"  -  Thomas Aquinas

    Divine (or Eternal) Law   -  The most perfect law, known only to God, or to man through revelation (the Ten Commandments and the Gospels)    

    Positive Law  -  The least perfect law, laws made by specific societies for their own governance.  They are purely human creations, either simple conventions, or "merely morally permissible."  (e.g. God, or nature, does not care what side of the road a society drives on).

    Natural Law (The Law of Nature)  -  A set of rues about moral behavior, available to all rational beings despite their particular society or culture.  Positive laws are just when they adhere to, or at least do not violate, the laws of nature.  Aquinas taught that all human or positive laws were to be judged by their conformity to the natural law.  An unjust law is not a law, in the full sense of the word.  It retains merely the 'appearance' of law insofar as it is duly constituted and enforced in the same way a just law is, but is itself a 'perversion of law.'  At this point, the natural law was not only used to pass judgment on the moral worth of various laws, but also to determine what those laws meant in the first place.  This principle laid the seed for possible societal tension with reference to tyrants. 


Hugo Grotius  (1583 - 1645)  Dutch jurist