If my brain is a Turing machine, doesn't it pretty much follow that I can't pick out the standard model? How would I do that?
I've never got a fully satisfactory answer to this. Basically the natural numbers are (informally) a minimal model of peano arithmetic - you can never have any model "smaller" than them.
And it may be possible to fomarlise this. Take the second order peano axioms. Their model is entirely dependent on the model of set theory.
Let M be a model of set theory. Then I wonder whether there can be models M' and N of set theory, such that: there exists a function mapping every set of M to set in M' that preserves the set theoretic properties. This function...
Building on the very bad Gödel anti-AI argument (computers's are formal and can't prove their own Gödel sentence, hence no AI), it occurred to me that you could make a strong case that humans could never recognise a human Gödel sentence. The argument goes like this:
Now, the more usual way of dealing with human Gödel sentences is to say that humans are inconsistent, but that the inconsistency doesn't blow up our reasoning system because we use something akin to relevance logic.
But, if we do assume humans are consistent (or can become consistent), then it does seem we will never knowingly encounter our own Gödel sentences. As to where this G could hide and we could never find it? My guess would be somewhere in the larger ordinals, up where our understanding starts to get flaky.