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"Therefore, it's well within the realm of plausibility that the actual behavior of the universe is governed by uncomputable functions..." It's also well within

"Therefore, it's well within the realm of plausibility that the actual behavior of the universe is governed by uncomputable functions..." It's also well within the realm of plausibility that the behavior of the universe is governed by invisible, intangible unicorns. :-) If you can provide an example of something in the universe actually computing an theoretically uncomputable function, then there is a gigantic problem somewhere and everyone is going to have to do some re-thinking. If.

User23 5y ago
By definition nothing will ever compute an uncomputable function. You’re only stating a trivial truth that by itself fails to refute the conjecture that we live in a reality that has behaviors that cannot be accurately described by computable functions and that we are forever stuck with merely approximate computable models. In fact, so far we’re not able to completely computationally predict any behavior of reality. Even the marvelous theory of quantum electrodynamics is only shown to be accurate to, last I knew, about a dozen places. Due to an unfortunately widespread misunderstanding of the Church-Turing thesis, far too many otherwise intelligent persons with some CS knowledge are completely blinkered to the possibility that the universe could have behaviors that are real, but not describable with computable functions beyond approximately. The practicing laboratory scientists I’ve spoken with don’t generally share that defect since they’re used to everything being approximate.
- mannykannot 5y ago
  I think you have a valid point here, but it does not do anything to save this paper. The paper claims to have refuted the possibility of what Searle calls Strong AI, but speculating that the universe has behaviors not describable with computable functions does not justify that conclusion. As Simonh pointed out above [1], Strong AI does not imply or depend on everything about the universe being computable, and even if it did, mere speculation that some unknown thing about the universe might not be computable would not justify inferring that therefore Strong AI must be impossible. This paper is combination of an unargued-for tacit premise with a rather blatant case of burden shifting. [1] https://news.ycombinator.com/item?id=29291286 https://news.ycombinator.com/item?id=29291286

User23 5y ago

By definition nothing will ever compute an uncomputable function. You’re only stating a trivial truth that by itself fails to refute the conjecture that we live in a reality that has behaviors that cannot be accurately described by computable functions and that we are forever stuck with merely approximate computable models. In fact, so far we’re not able to completely computationally predict any behavior of reality. Even the marvelous theory of quantum electrodynamics is only shown to be accurate to, last I knew, about a dozen places. Due to an unfortunately widespread misunderstanding of the Church-Turing thesis, far too many otherwise intelligent persons with some CS knowledge are completely blinkered to the possibility that the universe could have behaviors that are real, but not describable with computable functions beyond approximately. The practicing laboratory scientists I’ve spoken with don’t generally share that defect since they’re used to everything being approximate.

mannykannot 5y ago
I think you have a valid point here, but it does not do anything to save this paper. The paper claims to have refuted the possibility of what Searle calls Strong AI, but speculating that the universe has behaviors not describable with computable functions does not justify that conclusion. As Simonh pointed out above [1], Strong AI does not imply or depend on everything about the universe being computable, and even if it did, mere speculation that some unknown thing about the universe might not be computable would not justify inferring that therefore Strong AI must be impossible. This paper is combination of an unargued-for tacit premise with a rather blatant case of burden shifting. [1] https://news.ycombinator.com/item?id=29291286 https://news.ycombinator.com/item?id=29291286