Classical liberalism is a political philosophy and ideology belonging to liberalism in which primary emphasis is placed on securing the freedom of the individual by limiting the power of the government.
The philosophy emerged as a response to the Industrial Revolution and urbanization in the 19th century in Europe and the United States.
It advocates civil liberties with a limited government under the rule of law, private property, and belief in laissez-faire economic policy.
Classical liberalism is built on ideas that had already arisen by the end of the 18th century, such as selected ideas of Adam Smith, John Locke, Jean-Baptiste Say, Thomas Malthus, and David Ricardo.
It drew on a psychological understanding of individual liberty, the contradictory theories of natural law and utilitarianism, and a belief in progress.
Both modern American conservatism and social liberalism split from Classical Liberalism in the early 20th century.
At that time conservatives adopted the Classic Liberal beliefs in protecting economic civil liberties.
Conversely social liberals adopted the Classical Liberal belief in defending social civil liberties.
Neither ideology adopted the pure Classical Liberal belief that government exists to protect both social & economic civil liberties.
Conservatism shares an ideological agreement on limited government in the area of preventing government restriction against economic civil liberties as embodied in the ability of people to sell their goods, services or labor to anyone they choose free from restriction except in rare cases where society's general welfare is at stake.
One example of classic liberalism's beliefs regarding the role of government is found in Thomas Hobbes's theory that government was created by individuals to protect themselves from one another.