The image of a stack of turtles came to mind after I left the shala today. Something about having my legs and arms moved about in Supta K.
So, in honor of getting kurmasana and supta kurmasana today, I have always liked this story:
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!"—Hawking, 1988, A Brief History of Time
Hawking uses it as an example of how what we think we know can seem ridiculous to others.. and as a reminder that it could later seem just as ridiculous to ourselves. How do we know what we know, he asks.
The same with yoga practice. How do we know what we know? The body and the mind change every day, and the practice reflects that. What seemed impossible one day is possible the next and vice versa (unfortunately, ha!)