The term Lost Generation refers to the writers and artists living in Paris after World War I. The violence of World War I, also called the Great War, was unprecedented and invalidated previous ideas about faith, life, and death. Traditional values that focused on God, love, and manhood dissolved, leaving Lost Generation writers adrift. They struggled with moral and psychological aimlessness as they searched for the meaning of life in a changed world. This search for meaning and these feelings of emptiness and aimlessness reflect some of the principle ideas behind existentialism. Existentialism is a philosophical movement rooted in the work of the Danish philosopher Søren Kierkegaard, who lived in the mid-1800s. The movement gained popularity in the mid-1900s thanks to the work of the French intellectuals Jean-Paul Sartre, Simone de Beauvoir, and Albert Camus, including Sartre’s Being and Nothingness (1943). According to existentialists, life has no purpose, the universe is indifferent to human beings, and humans must look to their own actions to create meaning, if it is possible to create meaning at all. Existentialists consider questions of personal freedom and responsibility. Although Hemingway was writing years before existentialism became a prominent cultural idea, his questioning of life and his experiences as a searching member of the Lost Generation gave his work existentialist overtones.