Some of the major causes of imperialism have previously been the need for resources to supply the industrial revolution with raw materials, maintaining a supply of cheap labor and the desire to sustain a steady market for exported manufactured goods. To the benefit of a stronger nation intent on developing its economic and political strength through means outside of its borders, a weaker nation's economic, cultural and political systems are dominated. Imperialism, in contrast to colonialism, is a centrally developed state policy that is enacted for both economic and ideological reasons.
Differing perspectives exist on the subject of imperialism. The American sociologist, Lewis Samuel Feuer, identifies two subtypes of imperialism: progressive imperialism and regressive imperialism. Progressive imperialism is based on a cosmopolitan view of humanity in which the ruling nation is offering the controlled nation's allegedly backward people an opportunity to better living standards and assimilation into the more advanced imperial nation's society. Regressive imperialism is described by Feuer as based purely on a desire for conquest, exploitation and the reduction of undesired inhabitants to make room for those considered desirable.
The English economist John A. Hobson criticizes imperialism by identifying it with a nation's belief that the earth should be governed and developed by "those races who can do the work best." The term "imperialism" is often used as a pejorative, particularly when criticizing a nation's expansionist policies, whether they are forcibly imposed or obtained through indirect means.