Gödel's Incompleteness Theorems Import on Natural Languages?

Shawn July 02, 2024 at 11:31 3975 views 16 comments
If it were possible to extend the import of Gödel's incompleteness theorems on non-formal languages, then what would they be?

Comments (16)

Shawn July 03, 2024 at 21:02 #914377
So, since definitions are circular and the scope of natural languages take place in the world itself, then do you think that there's anything that can be said about Gödel's incompleteness theorems, within such a context?
Deleted User July 03, 2024 at 21:59 #914387
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Shawn July 03, 2024 at 22:04 #914388
Quoting tim wood
I'll bite. Non-formal language is descriptive, as such useful - "true" - wrt certain criteria, and as such never itself the truth. And the same for formal/technical language, the efference being that those users usually do not worry about truth.


So, I think you are right about the centrality of truth in formal systems with axioms. Therefore, do you think that the very fact that we have circular definitions in our natural language denies what Gödel's incompleteness theorems can say about such languages?
Deleted User July 03, 2024 at 22:10 #914391
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Shawn July 03, 2024 at 22:15 #914392
Quoting tim wood
I don't think Godel's has anything to do with natural languages.


Why is that? What makes his theorems unapplicable to natural languages?
Deleted User July 03, 2024 at 22:18 #914394
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TonesInDeepFreeze July 03, 2024 at 22:49 #914404
Reply to Shawn

Godel-Rosser is:

If T is a consistent formal theory adequate for arithmetic, then T is incomplete.

The steps in the proof depend on T being a formal theory.

What would "extend the import to non-formal languages" mean?
Shawn July 03, 2024 at 22:55 #914405
Quoting TonesInDeepFreeze
What would "extend the import to non-formal languages" mean?


As the topic progressed, I simply will rephrase the OP to look, as the following:

Are Gödel's incompleteness theorems applicable to non-formal languages?

If so, then the question follows, if it doesn't then it does not. Therefore, I think the need for that condition to be met is a sine qua non for Gödel's incompleteness theorems to have anything to do with non-formal languages, such as natural languages.

Thank you.
TonesInDeepFreeze July 04, 2024 at 00:21 #914428
Some people believe that Godel-Rosser has implications not confined to mathematics and questions in the philosophy of mathematics. They argue that Godel-Rosser pertains to questions in epistemology, ontology, and even other subjects. But I don't know what you mean by 'applicable to non-formal languages'.

An excellent book that discusses arguments about Godel-Rosser outside of mathematics and philosophy of mathematics is 'Godel's Theorems' by Torkel Franzen.
Shawn July 04, 2024 at 00:37 #914433
At the sake of sounding incoherent, I just wanted to provide my rationale for asking (what I perceive) a fundamental question about formal and non-formal languages where Gödel's incompleteness theorems can apply.

What I suppose is the fundamental question is at which point does Gödel's incompleteness theorems manifest their truth in a natural language, if applicable?

Quoting TonesInDeepFreeze
But I don't know what you mean by 'applicable to non-formal languages'.


I suppose this is a statement more apt for discussion under the guise of T-schema's and Tarski's undefinability theorem, no?

Quoting TonesInDeepFreeze
An excellent book that discusses arguments about Godel-Rosser outside of mathematics and philosophy of mathematics is 'Godel's Theorems' by Torkel Franzen.


Yes, thanks for this. I'll be sure to give it a look.
TonesInDeepFreeze July 04, 2024 at 01:03 #914446
Reply to Shawn

Yes, Tarski was very much concerned with both formal and natural languages.
180 Proof July 04, 2024 at 01:07 #914447
Reply to Shawn Very marginal, imho. Read Philosophical Investigations instead.
Tarskian July 04, 2024 at 01:29 #914452
Quoting Shawn
If it were possible to extend the import of Gödel's incompleteness theorems on non-formal languages, then what would they be?


We could possibly relax the definition of the predicate isProvable(n) to isRational(n). Say that if the majority of the observers believe that a natural-language sentence is rational, then it is.

In that case, by using the diagonal lemma, we can assert that:

In natural language, there exists a false sentence that is rational or a true sentence that is not rational, or both.

Next, for the same reasons as for Godel's theorem, we can safely assert that the overwhelming majority of true sentences in natural language are not rational.
Shawn July 04, 2024 at 01:35 #914453
Quoting 180 Proof
Very marginal, imho. Read Philosophical Investigations instead.


Yes, I have something to say about how Wittgenstein approached Gödel's incompleteness theorems as logical paradoxes. Namely, because Wittgenstein took the world as the totality of facts, not things, then the sum total of facts operating in the state of affairs of the world, necessitates that logic takes care of itself.

There's no Neo or glitch in the system itself...

Everything is a tautology...
Shawn July 04, 2024 at 02:18 #914461
Quoting Tarskian
We could possibly relax the definition of the predicate isProvable(n) to isRational(n). Say that if the majority of the observers believe that a natural-language sentence is rational, then it is.


Yet, is rationality truth-apt, as you've defined it? At least if it's epistemologically denoted, then these observational sentences are truth-apt, no?
Tarskian July 04, 2024 at 02:26 #914462
Quoting Shawn
Yet, is rationality truth-apt, as you've defined it? At least if it's epistemologically denoted, then these observational sentences are truth-apt, no?


Yes, it is limited to logic sentences expressed in natural language.

-- It is raining now. -> part of the universe of sentences under consideration for rational incompleteness.

-- Eat with fork and knife! -> not part of this universe.

Hence, it is only about sentences that can have a truth value.

Most true sentences will turn out to be irrational, if only, for model-theoretical reasons. They will be true in one model/interpretation but not in one or more other ones. Rationality has the same problem as provability.