“Existentialism is a term applied to the work of a number of philosophers since the 19th century who, despite large differences in their positions, generally focused on the condition of human existence, and an individual’s emotions, actions, responsibilities, and thoughts, or the meaning or purpose of life. Existential philosophers often focused more on what they believed was subjective, such as beliefs and religion, or human states, feelings, and emotions, such as freedom, pain, guilt, and regret, as opposed to analyzing objective knowledge, language, or science.”
“The early 19th century philosopher Søren Kierkegaard is regarded as the father of existentialism. He maintained that the individual is solely responsible for giving his or her own life meaning and for living that life passionately and sincerely, in spite of many existential obstacles and distractions including despair, angst, absurdity, alienation, and boredom.”
From Wikipedia: http://en.wikipedia.org/wiki/Existentialism
Stumbling along the sidewalk 