The 20th century brought with it upheavals that produced a series of conflicting developments within philosophy over the basis of knowledge and the validity of various absolutes. With classical certainties thought to be overthrown, and new social, economic, scientific, ethical, and logical problems, 20th-century philosophy was set for a series of attempts variously to reform, preserve, alter, abolish, previously conceived limits.
Just as profoundly, historical events such as the World Wars, the Russian Revolution, the near collapse of European parliamentary democracy in the 1930s and 1940s, the Holocaust, the use of atomic weapons on Imperial Japan, continued colonial violence, the foundation of the United Nations, the elaboration of new doctrines of human rights, the Vietnam War, the failure of revolutionary sentiment in 1968, the collapse of the Soviet Union and its client states, continuing inequities in global development and civil society, the resurgence of "fundamental" religious identity in Christian, Jewish, Islamic, and Hindu contexts, and seemingly irrepressible if intermittent genocidal activity called into question many philosophical doctrines on human rationality and created ever sharper demands on moral, political philosophy, and philosophy of religion.