Existentialism ( ) is a form of philosophical inquiry that explores the problem of human existence and centers on the subjective experience of thinking, feeling, and acting. For example, in the view of an existentialist, the individual's starting point has been called "the existential angst", a sense of dread, disorientation, confusion, or anxiety in the face of an apparently meaningless or absurd world. Existentialist thinkers frequently explore issues related to the meaning, purpose, and value of human existence. Existentialism is associated with several 19th- and 20th-century European philosophers who shared an emphasis on the human subject, despite often profound differences in thought. Among the earliest figures associated with existentialism are philosophers Søren Kierkegaard and Friedrich Nietzsche and novelist Fyodor Dostoevsky, all of whom critiqued rationalism and concerned themselves with the problem of meaning. In the 20th century, prominent existentialist thinkers included Jean-Paul Sartre, Albert Camus, Martin Heidegger, Simone de Beauvoir, Karl...