According to wikipedia, turing machines can be equipped with oracles that solve the halting problem; but then a new halting problem arises - whether machines equivalent to themselves ie with the oracle will halt. This gives rise to a hierarchy of turing machines with increasingly difficult halting problems. (This hierarchy can be continued into the transinfinite (ordinal) realm by using ordinal arithmetic, which shows that there are profoundly Oracular oracles or equivalently profoundly difficult halting problems).
Supposing, as some posit, that the universe is a Turing machine, and given that there is a well-defined theoretical hierarchy of Turing machines of differing strength what evidence do we have that the universe must be the simplest one, that is the first in this term? Other than using Occams Razor and simply taking the choice of the simplest? Could in fact it be equipped with an Oracle of some kind?
Note: Oracles as an idea was posited by Turing as a choice machine but not pursued or elaborated by him.