Existentialism is philosophical and literary tendency that typically displays a dismissal of abstract theories that seek to disguise the untidiness of actual human lives and emphasizes the subjective realities of individual existence, individual freedom, and individual choice. It is virtually impossible to define absolutely as it is now so broad in its approaches but some of its major strands can be outlined.

There is an emphasis on each person finding their own way in life, on making choices, (including, in particular, all serious and momentous life-choices), for oneself as one sees fit without reliance on external standards or practice. This tendency to effectively deny that there is an acceptable basis for moral decision making diverges markedly from an earlier, and often largely unquestioned faith-related, emphasis that there could be, and indeed were, moral standards to which all might beneficially conform.

Whereas an acceptance of moral standards could provide an objective basis for making choices Existentialism's denial of the existence of moral standards means that the primary basis for the making of choices has to be subjective. Persons actively engaged in situations may well make choices that are subjectively valid in terms of themselves, there and then, but which might seem questionable to a dispassionate observer.

There is a full acceptance that individuals are free to choose their own path and an associated declaration that individuals must accept the risk and responsibility of following their commitment wherever it leads. Choices made tend to establish the subsequent pattern of individuals’ lives and also profoundly influence the ensuing nature and aspect of the person who makes them. Even choosing not to make a choice is a form of choice bringing with it consequences. People are inevitably faced with choice in very many contexts.

One of the life choices Kierkegaard thought that people could make, and the one that he chose for himself, was a life fully aligned with faith. In contrast to this Nietzsche, who was himself descended from a recent background of Lutheran, clerical, ancestry proclaimed that "God is dead" and went on to endorse an, heroic, pagan ideal.

The respective approaches of Kierkegaard, Nietzsche and Sartre are considered in more detail on some of our other pages. The fashion for Existentialism after the Second World War saw its influence pervading widely and deeply into journalism, poetry, the playhouse, and the cinema. The outlook of the modern world has been formed, perhaps more than we readily appreciate, by Existentialist philosophy as advertised and sponsored from many sides.

Existentialist philosophy has developed two main aspects i.e. "Christian" and "Humanist". Apart from Kierkegaard's initial impetus the "Christian" aspect has had such main contributors as the German Protestant theologians Paul Tillich and Rudolf Bultmann, the French Roman Catholic theologian Gabriel Marcel, the Russian Orthodox philosopher Nikolay Berdyayev, and the German Jewish philosopher Martin Buber.

Apart from Nietzsche and Sartre the "Humanist" aspect can claim to find representation in the works of European based writers such as Jaspers, Dostoyevsky, Kafka, Malraux, Camus and Beckett and also such American based writers as Mailer and Miller.