"... an attitude that is poised between gaiety and gravity, between mirth and tragedy, and which the Greeks designated by the inimitable expression: Aneer spoudogeloios - the 'grave-merry' man. Such a man is capable of making his life into a game, and a very lovely one at that, because he knows that this life is either a comedy or a tragedy. 'Fun and gravity are sisters' [Plato]... In Christian truth this apparent contradiction is resolved into that grave mirth from which the tragic is wholly absent and which led Clement of Alexandria to speak of life as a 'divine children's game'.
I am trying to make plain that such a man is really always two men in one: he is a man with an easy gaiety of spirit, one might almost say a man of spiritual elegance, a man who feels himself to be living in invincible security: but he is also a man of tragedy, a man of laughter and tears, a man, indeed, of gentle irony, for he sees through the tragically ridiculous masks of the game of life and has taken the measure of the cramping boundaries of our earthly existence.
If one is only the first of these two things, we must write him down as a frivolous person who has, precisely, played himself out. If he is only the second, then we must account him as one who cannot conquer despair. It is the synthesis of the two things that makes the Homo ludens, the 'grave-merry' man, the man with a gentle sense of humor who laughs despite his tears, and finds in all earthly mirth a sediment of insufficiency".
[Hugo Rahner, Homo ludens]