Infallible Regress

For those of you who need infallibility, James Swan's conversation with Leo is typical.

Leo responded:

-If the Pope has the authority of God on earth, then there you have it, now, what do you mean "regress"?

A quick response:

If he's infallible, then you have to have a way to know infallibly whether what he said yesterday is infallible.
If it is, you need to know infallibly whether that way to know infallibly whether what he said yesterday is infallible is infallible.
If you solve that, you need an infallible interper to tell you the infall interp of what he said.
If you solve that, you need an infallible interper to tell you the infall interp of the infall interp of what he said.
If you solve that, you need an infallible interper to tell you the infall interp of the infall interp of the infall interp of what he said.