Natural law or the law of nature has been described as a law whose content is set by nature and that therefore is universal. As classically used, natural law refers to the use of reason to analyse human nature and deduce binding rules of moral behaviour. The phrase natural law is opposed to the positive law (meaning "man-made law", not "good law"; see posit) of a given political community, society, or nation-state, and thus can function as a standard by which to criticize that law. In natural law jurisprudence, on the other hand, the content of positive law cannot be known without some reference to the natural law (or something like it). Used in this way, natural law can be invoked to criticize decisions about the statutes, but less so to criticize the law itself.
Although natural law is often conflated with common law, the two are distinct in that natural law is a view that certain rights or values are inherent in or universally cognizable by virtue of human reason or human nature, while common law is the legal tradition whereby certain rights or values are legally cognizable by virtue of judicial recognition or articulation. Natural law theories have, however, exercised a profound influence on the development of English common law.