Existentialism 存在主義
The term is often seen as a historical convenience as it was first applied to many philosophers in hindsight, long after they had died. In fact, while existentialism is generally considered to have originated with Kierkegaard, the first prominent existentialist philosopher to adopt the term as a self-description was Jean-Paul Sartre. Sartre posits the idea that "what all existentialists have in common is the fundamental doctrine that existence precedes essence", as scholar Frederick Copleston explains. According to philosopher Steven Crowell, defining existentialism has been relatively difficult, and he argues that it is better understood as a general approach used to reject certain systematic philosophies rather than as a systematic philosophy itself. Sartre himself, in a lecture delivered in 1945, described existentialism as "the attempt to draw all the consequences from a position of consistent atheism".
Although many outside Scandinavia consider the term existentialism to have originated from Kierkegaard himself, it is more likely that Kierkegaard adopted this term (or at least the term "existential" as a description of his philosophy) from the Norwegian poet and literary critic Johan Sebastian Cammermeyer Welhaven. This assertion comes from two sources. The Norwegian philosopher Erik Lundestad refers to the Danish philosopher Fredrik Christian Sibbern. Sibbern is supposed to have had two conversations in 1841, the first with Welhaven and the second with Kierkegaard. It is in the first conversation that it is believed that Welhaven came up with "a word that he said covered a certain thinking, which had a close and positive attitude to life, a relationship he described as existential". This was then brought to Kierkegaard by Sibbern.
The second claim comes from the Norwegian historian Rune Slagstad, who claims to prove that Kierkegaard himself said the term "existential" was borrowed from the poet. He strongly believes that it was Kierkegaard himself who said that "Hegelians do not study philosophy 'existentially'; to use a phrase by Welhaven from one time when I spoke with him about philosophy". On the other hand, the Norwegian historian Anne-Lise Seip is critical of Slagstad, and believes the statement in fact stems from the Norwegian literary historian Cathrinus Bang.
存在主义（英语：Existentialism），是一个哲学的非理性主义思潮，它認為人存在的意義是無法經由理性思考而得到答案的，以强调个人、獨立自主和主观经验。尼采和祁克果可被看作其先驱。在20世纪中它流傳非常廣泛，其哲學思想還延續到了60年代興起的人本主義。雅斯贝尔斯和海德格尔、保羅·萨特和作家加缪是其代表人物。
其最突出的命題是：世界沒有終極的目標；人們發現自己處於一個隱隱約約而有敵意的世界中；人們選擇而且無法避免選擇他們的品格、目標和觀點；不選擇就是一種選擇，即是選擇了「不選擇」；世界和我們的處境的真相最清楚地反映在茫然的心理不安或恐懼的瞬間。
這些命題曾經影響了文學（例如：費奧多爾·陀思妥耶夫斯基和加繆）、精神分析學（例如：賓斯萬格和羅洛·梅）和神學（例如：保羅·田立克）。
其最著名和最明確的倡議是让-保罗·萨特的格言：“存在先於本質”（法语：l'existence précède l'essence）。他的意思是说，除了人的生存之外沒有天經地義的道德或靈魂。道德和靈魂都是人在生存中創造出來的。人沒有義務遵守某個道德標準或宗教信仰，卻有選擇的自由。要評價一個人，要評價他的所作所為，而不是評價他是個什麼人物，因為一個人是由他的行動來定義的。
萨特否认神或其它任何预先定义的规则的存在。让-保罗·萨特反对任何人生中「阻逆」的因素，因为它们缩小人的自由选择的余地。假如没有这些阻力的话，那么一个人的唯一的要解决的问题是他选择哪一条路走。然而人是自由的；即使他在自欺中，仍有潜力与可能。萨特也提出：「他人即是地狱」。这一观点看似与「人有选择的自由」观点相矛盾，其实每个人选择是自由的，但对于选择后的结果，每个人有无法逃避的责任，人在选择的过程中，面对的最大问题就是他人的选择，因为每个人都有选择的自由，但每个人的自由就可能影响他人的自由，所以称「他人即是地狱」。
存在主義並沒有否定神的存在，例如祁克果就是一名基督徒，他認為存在主義是基督徒思想模式的開始。尼采他在其著作《快樂的科學》（la gaya scienza）中提出「上帝已死」的說法，尼采並不是說上帝在形而下的層面已死；相反地，尼采明白到上帝已死代表現存道德標準的危機。
