I think I first saw the expression “Turtles all the way down,” when I read Carl Sagan’s Broca’s Brain: Reflections on the Romance of Science. He recounted it as a conversation between a Western traveler and an Oriental philosopher.
I don’t have that book handy, but it is also told in Stephen Hawking’s A Brief History of Time which is on a nearby shelf (actually, I have both the illustrated edition, and the “in a nutshell” versions which I found easier to understand).
A well-known scientist (some say it was Bertrand Russell) once gave a public lecture on astronomy. He described how the earth orbits around the sun and how the sun, in turn, orbits around the center of a vast collection of stars called our galaxy. At the end of the lecture, a little old lady at the back of the room got up and said: “What you have told us is rubbish. The world is really a flat plate supported on the back of a giant tortoise.” The scientist gave a superior smile before replying, “What is the tortoise standing on?” “You’re very clever, young man, very clever”, said the old lady. “But it’s turtles all the way down!”
If you search a bit online, you’ll also find it called “The Infinite Turtle Theory” and find that it has found its way into a good number of cultural works. I myself have pinned the saying to several web pages I have online.
Although Hawking relates the anecdote more to point out something about ridiculous theories that can’t be proven, others actually use it as a way to discuss an infinite regression belief about the origin and nature of the universe.
When I encountered it, I immediately thought of it as a variation on ancient beliefs that the world is borne through the universe on the back of an animal. In many Native American creation myths, it is a turtle that holds up the world called “Turtle Island.”
I also found that it might possibly be similar to some Indian classical texts, including the myth that the tortoise Chukwa supports the elephant Maha-pudma who holds up the world.
The reference to Bertrand Russell may be from a 1927 lecture he gave titled “Why I Am Not a Christian” during which he said:
“If everything must have a cause, then God must have a cause. If there can be anything without a cause, it may just as well be the world as God, so that there cannot be any validity in that argument. It is exactly of the same nature as the Hindu’s view, that the world rested upon an elephant and the elephant rested upon a tortoise; and when they said, “How about the tortoise?” the Indian said, “Suppose we change the subject.”
But you could go back to John Locke in 1690 (“An Essay Concerning Human Understanding“) where he refers to an Indian who said the world was on an elephant which was on a tortoise “but being again pressed to know what gave support to the broad-backed tortoise, replied — something, he knew not what.”
A more modern allusion to it supposedly came from William James (father of American psychology) who supposedly had a conversation with an old lady who told him the Earth rested on the back of a huge turtle.
“But, my dear lady”, James asked, “what holds up the turtle?”
“Ah”, she said, “that’s easy. He is standing on the back of another turtle.”
“But would you be so good as to tell me what holds up the second turtle?”
“It’s no use, Professor”, said the lady, avoiding a logical trap. “It’s turtles, turtles, turtles, all the way!”
Ah yes, we will never get to the bottom of some things.
Infinite regressions. What existed before the universe existed? If God created the universe, what created God?
It’s turtles all the way down.