benelliott comments on No coinductive datatype of integers - Less Wrong

4 Post author: cousin_it 04 May 2011 04:37PM

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Comment author: benelliott 05 May 2011 08:18:38PM *  4 points [-]

You are right, in that those statements do satisfy the conclusion, and I don't see why you're being downvoted. The difference between them and the original, self referential, statement is generality. For example:

You: I know that ZF set theory is incomplete because the axiom of choice cannot be proven within it.

Some other guy: Okay then, how about we add the axiom of choice as another axiom, maybe this new system will be complete?

You: Nope, it still can't prove or disprove the continuum hypothesis.

SUG: So I'll add that in as another axiom, maybe that will finally patch it?

You: Nope, still doesn't work because ...

SUG: But if I add that as an axiom as well...

Hopefully you can see why this might keep going for quite a while, and given that its quite difficult to prove a statement is undecidable you will run out eventually. There's nothing you can do to convince him those undecidable statements are symptoms of a general problem rather than just one-time flaws.

Compare to this:

Godel: ZF set theory is not complete, because I have this self-referential construction of an unprovable statement.

SUG: But what if I add your statement as another axiom?

Godel: Then my proof still applies to this new system you created, and I can construct another, similar statement.

SUG: But what if I...

Godel: There's no point in you trying to continue this, whatever system you create my theorem will always apply.

SUG: Drat! Foiled again!

Comment author: Cyan 06 May 2011 12:35:16AM 0 points [-]

(Why is some other guy SUG and not SOG? Oversight? Euphony?)

Comment author: benelliott 06 May 2011 07:35:10AM 0 points [-]

Because I evidently can't spell :(