An English philosopher was visiting India, and was introduced to a holy  man. The philosopher asked the Holy Man the nature of the world, and  the old man replied, "Oh, the world is a great big ball that sits on the great flat back of the Great World Turtle."

The Englishman of course asked "What does the turtle stand on?"

The seer replied "Why on the back of an even larger turtle of course!"

Then the Englishman asked, "And what does this turtle stand on?"

 The old man shook his head and sweetly smiled and said, "It's no use, my son;  it is turtles all the way down!"

[SPC:  There are many versions of this story.  Some people give Bertrand Russell as its originator (and/or protagonist), some William James, some Isaac Asimov.  The point of the story represents one horn of the so-called "Münchhausen Trilemma" (Albert 1985), which Jürgen Habermas's (1983/1990) discourse ethics relies on.]

Albert, Hans (1985).  Treatise on Critical Reason.  Princeton, NJ:  Princeton University Press.
Habermas, Jürgen (1983/1990).  Moral Consciousness and Communicative Action. Cambridge, MA:  MIT.