Social Darwinism was the application of Darwin's theory of evolution and natural selection to human society. It asserted that the wealthy were successful because they were stronger and more fit, while the poor were poor because they were weaker. This view legitimized the success of the powerful and allowed them to continue oppressing workers. The Gospel of Wealth extended these ideas by arguing that it was the duty of the wealthy to promote social progress through philanthropy, thus giving the strongest poor a chance to rise up, while still believing that poverty resulted from innate weakness. Both Social Darwinism and the Gospel of Wealth justified growing inequality and the dominance of the rich.