How did social darwinism paralleled the economic doctrine of laissez-faire?

Social Darwinism is based off of Darwin's theory of evolution and natural selection. This translates all of that into economic terms, so, essentially, Social Darwinism is about allowing the best businesses to rise, and the inferior ones to fail. This mirrors Laissez Faire doctrines, as an involved government may try to save failing businesses. Both of these are usually found together because the Government is un-involved in both.