Call the world as it presents itself to us world-1
The regularity & order in the world demands explanation - hence we have a mathematically consistent description of the world. Call this world-2.
But surely the same situation again applies here: that the regularity & order is manifestly displayed in world-2 demands an explanation. Suppose that this is another mathematically consistent explanation for this. Call this world-3.
and so on.
We appear to have an infinite regress. Does this mean that any mathematical description of the world can never be complete in itself?
A rough example of this is the description of our own universe in the standard model. Then the explanation of fine-tuning demands explanation - some treatments consider then the perspective of a larger multiverse.