Natural rights ( a la Locke) says that man has rights that are not able to be given away or taken away, and are thus inalienable . Chief among these are life, liberty and property. Liberty is a property that adheres to the individual, not originating from society or from any social contract. Classical republicanism follows the classical political thinkers of Cicero and other Greek political thinkers. Most controversial is the classical republican view of liberty and how, or if, this view differed from that later developed by liberalism. Previously, many scholars accepted the stance of Isaiah Berlin that republicanism was tilted more toward positive liberty rather than the negative liberty characterizing liberalism. In recent years this thesis has been challenged, and Philip Pettit argues that republican liberty is based upon "non-domination" while liberal freedom is based upon "non-interference." Another view is that liberalism views liberty as pre-social while classical republicans saw true liberty as a product of society. Because liberty was an important part of republican thought, many republican thinkers were appropriated by theory of classical liberalism. The source of liberty in natural rights is the individual; in classical republicanism, it's society.