Russell’s Second Conjecture, that “It’s turtles all the way down”, has only been demonstrated for the first 107 turtles. It has been shown to be mathematically equivalent to the Riemann Hypothesis, so if a tortoise or terrapin is found, the corollary follows that there must be a corresponding non-trivial zero of the Zeta Function with a real part ≠ ½.
Both conjectures are equivalent to Dunsany’s Recursive Theology, which states that it’s chess-playing gods all the way up.