Existentialism (/ˌɛɡzɪˈstɛnʃəlɪzəm/[1] or /ˌɛksəˈstɛntʃəˌlɪzəm/[2]) is a form of philosophical enquiry that explores the nature of existence by emphasizing experience of the human subject—not merely the thinking subject, but the acting, feeling, living human individual.[3] In the view of the existentialist, the individual's starting point has been called "the existential angst" (or, variably, existential attitude, dread, etc.), or a sense of disorientation, confusion, or anxiety in the face of an apparently meaningless or absurd world.[4]

Existentialism is associated with several 19th- and 20th-century European philosophers who shared an emphasis on the human subject, despite profound doctrinal differences.[5][3][6] Many existentialists regarded traditional systematic or academic philosophies, in style and content, as too abstract and remote from concrete human experience.[7][8] A primary virtue in existentialist thought is authenticity.[9] Søren Kierkegaard is generally considered to have been the first existentialist philosopher,[5][10][11] though he did not use the term existentialism.[12] He proposed that each individual—not society or religion—is solely responsible for giving meaning to life and living it passionately and sincerely, or "authentically".[13][14]

The main idea of existentialism during the World War II was developed by Jean-Paul Sartre under the influence of Dostoevsky and Martin Heidegger, whom he read in a POW camp and strongly influenced many disciplines besides philosophy, including theology, drama, art, literature, and psychology.[15]