Question about logic
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22-02-2014, 01:17 AM
RE: Question about logic
(22-02-2014 01:16 AM)Chippy Wrote:  
(21-02-2014 09:56 PM)donotwant Wrote:  No. Logic is based on 3 unbreakable laws of of identity, non-contradiction and excluded middle. They can be proven by absurdity of their falsehood.

Yes but the OP is concerned with a justification of the three laws of classical logic and you have not provided one.

"They can be proven by absurdity of their falsehood" doesn't get you anywhere because you are appealing to induction and induction will not give you the universality that you need to justify your use of the word "proven".

If they can be broken then they can't be broken. Think about it.
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22-02-2014, 01:24 AM
RE: Question about logic
(22-02-2014 01:17 AM)donotwant Wrote:  If they can be broken then they can't be broken. Think about it.

I have thought about it and I even gave you examples in another thread. Many-valued logics violate the law of the excluded middle.
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22-02-2014, 01:27 AM
RE: Question about logic
(22-02-2014 01:24 AM)Chippy Wrote:  
(22-02-2014 01:17 AM)donotwant Wrote:  If they can be broken then they can't be broken. Think about it.

I have thought about it and I even gave you examples in another thread. Many-valued logics violate the law of the excluded middle.

I know the fuzzy sets. They don't violate anything. Fuzzy logic instead of using hot - not hot dichotomy uses hot - 3/4 hot - half hot - 1/4 hot - not hot.
It's useful on design of machines but it's not some new logic in the sense you speak of. In classic logic the 3/4 hot is either classified hot or not hot. Depends on how you define hot. There is no violation.
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22-02-2014, 01:56 AM
RE: Question about logic
(22-02-2014 01:27 AM)donotwant Wrote:  
(22-02-2014 01:24 AM)Chippy Wrote:  I have thought about it and I even gave you examples in another thread. Many-valued logics violate the law of the excluded middle.

I know the fuzzy sets. They don't violate anything. Fuzzy logic instead of using hot - not hot dichotomy uses hot - 3/4 hot - half hot - 1/4 hot - not hot.
It's useful on design of machines but it's not some new logic in the sense you speak of. In classic logic the 3/4 hot is either classified hot or not hot. Depends on how you define hot. There is no violation.

Fuzzy logic is just one of several many-valued logics. Many-valued logics are named such because they do violate the law of the excluded middle.[1] There is a violation because a proposition can have something other than T or F as its value. Pretending they don't exist isn't a counter-argument.
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22-02-2014, 01:59 AM
RE: Question about logic
(22-02-2014 01:56 AM)Chippy Wrote:  
(22-02-2014 01:27 AM)donotwant Wrote:  I know the fuzzy sets. They don't violate anything. Fuzzy logic instead of using hot - not hot dichotomy uses hot - 3/4 hot - half hot - 1/4 hot - not hot.
It's useful on design of machines but it's not some new logic in the sense you speak of. In classic logic the 3/4 hot is either classified hot or not hot. Depends on how you define hot. There is no violation.

Fuzzy logic is just one of several many-valued logics. Many-valued logics are named such because they do violate the law of the excluded middle.[1] There is a violation because a proposition can have something other than T or F as its value. Pretending they don't exist isn't a counter-argument.

What I'm saying is that just because you call something half hot and call it middle ground doesn't make it a middle ground.
half hot is not hot it's half hot. And it's either half hot or it's not half hot.
if it's half hot then it's not hot. So the absolutes still apply.
I know that these fuzzy sets exist and are used practically but they don't violate anything. As for proof of the absolutes the proof is that they apply to anything including themselves and if you assume they are not true it will lead to absurdities everywhere. Including falsehoods in reality.
Not to mention without em you can't even say they are not true because you assume they are true at that instant.
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22-02-2014, 09:28 AM
RE: Question about logic
I apologize for not jumping back in sooner, life stuff and all that. This conversation has certainly taken off though! To recap, my question was basically about a way I tried to prove that logic never proves itself, and that validating logical with real world empirical data would have to do it. I DO understand that there is a lot to be said about logical conclusion that are true but not so because of axioms that are true.

However, isn't it also true that the only way logic could evolve is with some sort of mechanism of testing axioms to see which are consistently true to find more truths? I imagine that it's a self evolving process where one would take proven conclusions and other observations to get to more conclusions, and assuming those conclusions are true restarting the process with THAT conclusion. A sort of process where truth begets more truth.

As for the posts about the three classical laws of logic, I always thought they originated from common sense being explained in such a way that even though it's not ALWAYS true, it's at least true in a paradigm that allows for certain levels of prediction. Once you see that some laws break the process of logic wouldn't break, it would just find new axioms to fit the new paradigm.

Quote:We may call both processes "reasoning" or "logic" but the point I'm making is that A and B are clearly not the same processes. Because If I thought to myself about how the world worked and, in order to see if that's how the world worked, I thought to myself about the workings of the world some more, I'd be circular indeed.
As i understand it a previous poster pointed out that we use logic even in the affirmation process. I think I can make a better analogy then: Proving that logic is "true" is less important than proving that it's useful. Like a hammer, all we care about is that the tool we have works.

It's only a debate if both parties are willing to let each other's opinions change their own.
If you aren't willing to change in light of learning more about what you fight for, what the hell are you doing expecting the other party to want to change?
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