Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
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PeteOlcott
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Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
Here is the simplest way to explain my system
(1) If there is a (connected sequence of valid deductions from true premises to a true conclusion) then X is TRUE: (F ⊢ X).
(2) If there is a (connected sequence of valid deductions from true premises to the negation of the conclusion) then X is FALSE: (F ⊢ ¬X).
(3) Otherwise X UNSOUND
We use the Axioms of formal systems in place of true premises and the conclusion of a formal proof is called a consequence.
(1) If there is a (connected sequence of valid deductions from true premises to a true conclusion) then X is TRUE: (F ⊢ X).
(2) If there is a (connected sequence of valid deductions from true premises to the negation of the conclusion) then X is FALSE: (F ⊢ ¬X).
(3) Otherwise X UNSOUND
We use the Axioms of formal systems in place of true premises and the conclusion of a formal proof is called a consequence.
Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
How do you know your premises are true?PeteOlcott wrote: ↑Fri Apr 26, 2019 2:53 pm (1) If there is a (connected sequence of valid deductions from true premises to a true conclusion) then X is TRUE: (F ⊢ X).
If by "true" all you mean is that they are your premises, then you are simply redefining the word "validity" with your own term "truth."
You've already said you don't believe in objective truth. Is that correct?
So if person X assumes that 2 + 2 = 4 and Y assumes that 2 + 2 = 5, then both of these things are true.
Is that your position?
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PeteOlcott
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Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
I know that my premises are true because they are semantic tautologies:wtf wrote: ↑Fri Apr 26, 2019 5:14 pmHow do you know your premises are true?PeteOlcott wrote: ↑Fri Apr 26, 2019 2:53 pm (1) If there is a (connected sequence of valid deductions from true premises to a true conclusion) then X is TRUE: (F ⊢ X).
https://www.britannica.com/topic/tautology
Tautology, in logic, a statement so framed that it cannot be denied
without inconsistency. Thus, “All humans are mammals” is held to
assert with regard to anything whatsoever that either it is a human
or it is not a mammal. But that universal “truth” follows not from
any facts noted about real humans but only from the actual use of
human and mammal and is thus purely a matter of definition.
Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
You ignored my question.PeteOlcott wrote: ↑Fri Apr 26, 2019 5:55 pm I know that my premises are true because they are semantic tautologies:
Person X stipulates the axiom 2 + 2 = 4.
Person Y stipulates the axiom 2 + 2 = 5.
Are both axioms true by virtue of being axioms?
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PeteOlcott
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Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
I think that most people would agree that person Y would be a liar forwtf wrote: ↑Fri Apr 26, 2019 7:10 pmYou ignored my question.PeteOlcott wrote: ↑Fri Apr 26, 2019 5:55 pm I know that my premises are true because they are semantic tautologies:
Person X stipulates the axiom 2 + 2 = 4.
Person Y stipulates the axiom 2 + 2 = 5.
Are both axioms true by virtue of being axioms?
directly contradicting mutually agreed upon conventions.
If person Y could come up with some set of axioms such as PA that
make their stipulation coherent (such as the distinction between
Euclidean and non-Euclidean geometry) then it would be acceptable.
Simply rearranging the finite strings that are associated with elements
of the order set of natural numbers would not count because it would
not change the actual axioms it would only provide an alternative
way that these same axioms could be encoded.
Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
I think most logicians would agree that this is a bandwagon fallacy.PeteOlcott wrote: ↑Fri Apr 26, 2019 7:47 pm I think that most people would agree that person Y would be a liar for
directly contradicting mutually agreed upon conventions.
All unique axioms lead to such distinctions.PeteOlcott wrote: ↑Fri Apr 26, 2019 7:47 pm If person Y could come up with some set of axioms such as PA that
make their stipulation coherent (such as the distinction between
Euclidean and non-Euclidean geometry) then it would be acceptable.
I thought you said that the only property an axiom has is "truth". You are now telling us that axioms have "encoding". Like encoding meaning, or what?PeteOlcott wrote: ↑Fri Apr 26, 2019 7:47 pm Simply rearranging the finite strings that are associated with elements
of the order set of natural numbers would not count because it would
not change the actual axioms it would only provide an alternative
way that these same axioms could be encoded.
Almost as if you can't decide if Tarski's is refuted or not.
Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
Then you agree that the truth value of a stipulative definition is subject to verification by conventions, authorities, or facts outside of the definition itself. Is that what you just said? You just defeated your entire argument.PeteOlcott wrote: ↑Fri Apr 26, 2019 7:47 pmI think that most people would agree that person Y would be a liar for
directly contradicting mutually agreed upon conventions.
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PeteOlcott
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Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
If person Y could come up with some set of axioms such as PA thatwtf wrote: ↑Fri Apr 26, 2019 7:10 pmYou ignored my question.PeteOlcott wrote: ↑Fri Apr 26, 2019 5:55 pm I know that my premises are true because they are semantic tautologies:
Person X stipulates the axiom 2 + 2 = 4.
Person Y stipulates the axiom 2 + 2 = 5.
Are both axioms true by virtue of being axioms?
make their stipulation coherent (such as the distinction between
Euclidean and non-Euclidean geometry) then it would be acceptable.
Then we would have two distinct formal systems each having their own
notion of truth relative that that formal system. It cannot contain any
contradictory axioms.
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PeteOlcott
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Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
No you are wrong. We do not require a whole new formal system every timeLogik wrote: ↑Fri Apr 26, 2019 7:59 pmAll unique axioms lead to such distinctions.PeteOlcott wrote: ↑Fri Apr 26, 2019 7:47 pm If person Y could come up with some set of axioms such as PA that
make their stipulation coherent (such as the distinction between
Euclidean and non-Euclidean geometry) then it would be acceptable.
that we add an axiom. We only need this when axioms form contradictions.
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PeteOlcott
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Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
Every axiom must have an associated finite string. It cannot simply sit inside someone's head.Logik wrote: ↑Fri Apr 26, 2019 7:59 pmI thought you said that the only property an axiom has is "truth". You are now telling us that axioms have "encoding". Like encoding meaning, or what?PeteOlcott wrote: ↑Fri Apr 26, 2019 7:47 pm Simply rearranging the finite strings that are associated with elements
of the order set of natural numbers would not count because it would
not change the actual axioms it would only provide an alternative
way that these same axioms could be encoded.
Almost as if you can't decide if Tarski's is refuted or not.
Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
I said nothing about PA. In fact these are one-sentence axiom systems. The entirety of the axiom system is:PeteOlcott wrote: ↑Sat Apr 27, 2019 12:08 am If person Y could come up with some set of axioms such as PA that
make their stipulation coherent (such as the distinction between
Euclidean and non-Euclidean geometry) then it would be acceptable.
* 2 + 2 = 5.
There are no inference rules and no other axioms. There's only one axiom. I just wrote it down. There are no inferences other than 2 + 2 = 5. That's a perfectly valid deduction in this axiom system.
Now that is the axiom that I've formulated, using your idea of a stipulative definition. According to your theory, it must be true by virtue of being an axiom.
But you just told me that the truth value of my axiom is subject to verification based on external factors: what everyone believes, or what experts believe, or perhaps actual facts.
You have fatally contradicted your own theory. Axioms are neither true nor false in and of themselves.
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PeteOlcott
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Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
No you are right that could be an axiom in its own formal system.wtf wrote: ↑Sat Apr 27, 2019 12:33 amI said nothing about PA. In fact these are one-sentence axiom systems. The entirety of the axiom system is:PeteOlcott wrote: ↑Sat Apr 27, 2019 12:08 am If person Y could come up with some set of axioms such as PA that
make their stipulation coherent (such as the distinction between
Euclidean and non-Euclidean geometry) then it would be acceptable.
* 2 + 2 = 5.
There are no inference rules and no other axioms. There's only one axiom. I just wrote it down. There are no inferences other than 2 + 2 = 5. That's a perfectly valid deduction in this axiom system.
Now that is the axiom that I've formulated, using your idea of a stipulative definition. According to your theory, it must be true by virtue of being an axiom.
But you just told me that the truth value of my axiom is subject to verification based on external factors: what everyone believes, or what experts believe, or perhaps actual facts.
You have fatally contradicted your own theory. Axioms are neither true nor false in and of themselves.
Because it contradicts many other formal systems it is excluded from them.
I think these things through more deeply as I get more feedback.
Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
I am gratified to have made my point.PeteOlcott wrote: ↑Sat Apr 27, 2019 1:02 am I think these things through more deeply as I get more feedback.
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PeteOlcott
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Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
Yes, your feedback and that of Logik has been useful.wtf wrote: ↑Sat Apr 27, 2019 1:05 amI am gratified to have made my point.PeteOlcott wrote: ↑Sat Apr 27, 2019 1:02 am I think these things through more deeply as I get more feedback.
Re: Eliminating Undecidability and Incompleteness in Formal Systems (As simple as possible)
Sure. But the meaning of strings is different from system to system.PeteOlcott wrote: ↑Sat Apr 27, 2019 12:13 am Every axiom must have an associated finite string. It cannot simply sit inside someone's head.
2+2 = 4 (decimal)
2+2 = 11 (ternary)
IF "=" means "semantic equivalence"
∴ 4 = 11
IF "=" means "symbolic equivalence" then it's false.