Racialist theories are frameworks that assert the belief in inherent differences among races, often ranking them hierarchically. These theories emerged in the late 19th and early 20th centuries, drawing on pseudoscientific principles that misapplied biological concepts to social contexts, leading to the justification of racial discrimination and colonialism. They often intersect with ideas from Darwinism and Social Darwinism, as proponents used these theories to claim that certain races were naturally superior or more evolved than others.