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Something like a Turing machine, with its finite states, deterministic transitions, and simple tape seems so mechanical, so physical. So predictable.

Sure, there's the halting problem, but that relies on a paradox.

Surely something as artifical as self-referential statements would seem a bit pointless.

And yet, with the help of that principle, it turns out we can write simple, mechanical programs where if the input is < N we can calculate the answer, and if the input is > N we can't figure out what the program will do (using standard mathematical thinking).

For some N we can get creative, but for a yet bigger N, we may well find ourselves unable to be creative enough to work out if we could ever work out the the answer.

https://en.wikipedia.org/wiki/Busy_beaver#Non-computability

"In 2016, Adam Yedidia and Scott Aaronson obtained the first (explicit) upper bound on the minimum n for which Σ(n) is unprovable in ZFC. To do so they constructed a 7910-state[2] Turing machine whose behavior cannot be proven based on the usual axioms of set theory (Zermelo–Fraenkel set theory with the axiom of choice), under reasonable consistency hypotheses (stationary Ramsey property).[3][4] This was later reduced to 1919 states, with the dependency on the stationary Ramsey property eliminated.[5][6]"



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