He is standing on the back of another turtle. Don't be too quick to laugh at this little old lady.
All human minds work on fundamentally similar principles.
As Dr. Leonard Orr has noted, the human mind behaves as if it were divided into two parts, the Thinker and the Prover. The Thinker can think about virtually anything. The Prover is a much simpler mechanism. Whatever the Thinker thinks, the Prover proves. To cite a notorious example which unleashed incredible horrors earlier in this century, if the Thinker thinks that all Jews are rich, the Prover will prove it.