Social Darwinism was the application of Darwin's theory of evolution and natural selection to human society. It argued that the poor were poor because they were weak and unfit, while the rich succeeded because they were strong and fit. This legitimized the success of the powerful and rich. The Gospel of Wealth extended these ideas by arguing that it was the duty of the wealthy to bring social progress through philanthropic works like libraries and schools, in order to give the poor opportunities to rise up and prove their fitness. However, both Social Darwinism and the Gospel of Wealth still viewed poverty as a sign of weakness and inferiority and helped perpetuate the oppression of the poor.