This paper explains that the fundamental liberal principle states that freedom is normatively basic; therefore, any political
authority and law must be justified because they limit the liberty of citizens. The social
contract theory, as developed by Thomas Hobbes, John Locke, Jean-Jacques Rousseau, and Immanuel Kant, is generally viewed as liberal. The author points out that the
classical liberals believe that private property is the only effective means for the protection of liberty, which results from a free market economy based on private property and protects the liberty of subjects against encroachments by the state. The paper relates that John Stuart Mill, 1806-1873, is the single best example of classical liberalism, representing the crossroads of English, French, and German strains of thought by warning against the tyranny of opinion, which silences other voices, calling for a form of intellectual tolerance and advocating the limitation of the state.