Vaniver comments on Second-Order Logic: The Controversy - Less Wrong

24 Post author: Eliezer_Yudkowsky 04 January 2013 07:51PM

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Comment author: [deleted] 19 March 2015 08:13:05AM *  0 points [-]

Technically speaking, you can observe the loop encoded in the Turing machine's code somewhere -- every nonhalting Turing machine has some kind of loop. The Halting theorems say that you cannot write down any finite program which will recognize and identify any infinite loop, or deductively prove the absence thereof, in bounded time. However, human beings don't have finite programs, and don't work by deduction, so I suspect, with a sketch of mathematical grounding, that these problems simply don't apply to us in the same way they apply to regular Turing machines.

EDIT: To clarify, human minds aren't "magic" or anything: the analogy between us and regular Turing machines with finite input and program tape just isn't accurate. We're a lot closer to inductive Turing machines or generalized Turing machines. We exhibit nonhalting behavior by design and have more-or-less infinite input tapes.

Comment author: Vaniver 19 March 2015 05:02:35PM 2 points [-]

The Halting theorems say that you cannot write down any finite program which will recognize and identify any infinite loop

I think I would use "every" where you use "any."

Comment author: [deleted] 19 March 2015 08:46:59PM *  0 points [-]

Let's just use quantifiers.

~exist P, forall M i, P (M, i) \/ ~P (M, i).

Where P is a finite program running in finite time, M is a Turing machine, and i is an input string.