Both "conservatism" and "liberalism" have had different meanings over time in different centuries. The term "liberal conservatism" has been used in quite different ways. It usually contrasts with aristocratic conservatism, which deems the principle of equality as something discordant with human nature and emphasizes instead the idea of natural inequality. As conservatives in democratic countries have embraced typical liberal institutions such as the rule of law, private property, the market economy and constitutional representative government, the liberal element of liberal conservatism became consensual among conservatives. In some countries such as the United Kingdom and the United States, the term "liberal conservatism" came to be understood simply as "conservatism" in popular culture, prompting some conservatives who embraced more strongly classical-liberal values to call themselves "libertarians" instead. However, there are differences between classical liberals and libertarians.