You guys might find this game interesting: Take A Walk With Me.
It's a different theme but it also tackles philosophical concepts in a contemplative, it's-not-really-a-game-but-it's-a-game way. With a philosophical game you still have to give the player some sort of action to perform, even if it is just walking or moving into a room or something, otherwise it's a film. It doesn't have to be a gamified action however.