Capitalism has been criticized for a number of reasons throughout history. Among them are the unreliability and instability of capitalist growth, production of social harms, such as pollution and inhumane treatment of workers, and forms of inequality attributed to capitalism, such as mass income disparity. Many capitalist critiques stem from the theories of Karl Marx, the 19th-century economist and philosopher whose work gave rise to Marxism. Some historians connect profit-driven economic models, such as capitalism and mercantilism, to the rise of oppressive institutions such as slavery, colonialism, and imperialism.