raison d'être = existential reason

raison d'être は以前紹介した単語ですが、existential reason （生きている理由、存在理由）です。1:11 why do you want this? to be acknowledged for who and what I am, no more, no less. not for acclaim, not for approval, but the simple truth of that recognition. this has been the elemental drive of my existence, and it must be achieved, if I am to live or die with dignity.

[Scene] Bicentennial Man - Right to Humanity (Part 2)
https://www.youtube.com/watch?v=kOPn6Y6pPPg  0:58 wow! existential.ロボットに魂がありますか？奥が深い質問だね。
The Doctor's Finest - Hannah Hart interviews Grant imahara - BBC America
https://www.youtube.com/watch?v=cbtMSlc1Kfc  1:13 it is an existential matter. 体制の存続問題。
Gordon Chang - A Lot Of People Are Losing Substantial Amounts In China - 20 Aug 15 | Gazunda
https://www.youtube.com/watch?v=JswfjZ7KZ-0  5:15 it could even be a greater existential threat to the Communist Party. 経済発展に伴う環境破壊は共産党の存続を脅かす問題だ。
Exposing The Changing Face Of Superpower China

1:14 my reason for being. 私の存在理由

Why Am I Me, Instead Of Someone Else?

参考リンク
http://bridge-english.blogspot.jp/2009/08/blog-post_9950.html  生き甲斐（生きがい）を英語でなんと言うか？

練習問題解答
b-4654 an existential threat