Law of non-contradiction

Started by Daniel, November 03, 2018, 05:12:41 AM

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Daniel

1.) How do we know that the law of non-contradiction is true?

2.) Do we know that the law of non-contradiction is true?

3.) Is the law of non-contradiction true?

Michael Wilson

We cannot refute the law of non-contradiction, without falling into logical contradiction; If we say that there is "no truth"; we are at once declaring that there is a truth, which is that there is no truth.
"The World Must Conform to Our Lord and not He to it." Rev. Dennis Fahey CSSP

"My brothers, all of you, if you are condemned to see the triumph of evil, never applaud it. Never say to evil: you are good; to decadence: you are progess; to death: you are life. Sanctify yourselves in the times wherein God has placed you; bewail the evils and the disorders which God tolerates; oppose them with the energy of your works and your efforts, your life uncontaminated by error, free from being led astray, in such a way that having lived here below, united with the Spirit of the Lord, you will be admitted to be made but one with Him forever and ever: But he who is joined to the Lord is one in spirit." Cardinal Pie of Potiers

james03

Start by 1.  You use the word "true".  Do you believe things can be true?
"But he that doth not believe, is already judged: because he believeth not in the name of the only begotten Son of God (Jn 3:18)."

"All sorrow leads to the foot of the Cross.  Weep for your sins."

"Although He should kill me, I will trust in Him"

Daniel

#3
Right... I see now that it's a logical contradiction.

- "There is no truth" is either true or false.
- It can't be true, since that's contradictory. (There's truth in the statement, yet the statement says there's no truth.)
- If false, then truth exists. (Because it is not the case that no truth exists... so some truth must exist.)

So we cannot conceive of the nonexistence of truth.

But I am now wondering... is it merely the case that we humans cannot conceive of the nonexistence of truth, perhaps because we lack some faculty or art allowing us to conceive that "truth does not exist" is, in some mysterious way, a true statement? Or is it the case that the nonexistence of truth is absolutely inconceivable? I'm guessing the latter, though I'm not sure I'm 100% convinced.

Tales

How many humans throughout history have discovered a non-truth truth or the non-existence of truth?  None?  Over billions of lived human years, trillions of lived human minutes, we've yet to experience or figure out a non-truth truth?

For some men, no amount of evidence is enough.

If the non-existence of truth is such the case then absolutely nothing makes sense.  Words do not mean what they mean.  Logic means nothing.  That you use words and logic to probe this question show how much nonsense it is.  Even if if were the case, you couldn't trust in anyway the method by which you came to know it.

Kreuzritter

Quote from: Michael Wilson on November 03, 2018, 11:52:30 AM
We cannot refute the law of non-contradiction, without falling into logical contradiction; If we say that there is "no truth"; we are at once declaring that there is a truth, which is that there is no truth.

You can't prove a "law of non-contradiction" by a reductio ad absurdum that assumes it. The second part has nothing to do with the question.

Kreuzritter

Quote from: Daniel on November 04, 2018, 03:06:32 PM
Right... I see now that it's a logical contradiction.

- "There is no truth" is either true or false.
- It can't be true, since that's contradictory. (There's truth in the statement, yet the statement says there's no truth.)
- If false, then truth exists. (Because it is not the case that no truth exists... so some truth must exist.)

So we cannot conceive of the nonexistence of truth.

But I am now wondering... is it merely the case that we humans cannot conceive of the nonexistence of truth, perhaps because we lack some faculty or art allowing us to conceive that "truth does not exist" is, in some mysterious way, a true statement? Or is it the case that the nonexistence of truth is absolutely inconceivable? I'm guessing the latter, though I'm not sure I'm 100% convinced.

If truth "didn't exist", whatever that means, that would be true. I don't know what your problem is in accepting such a priori proof as demonstrating an absolutely true statement about reality.

The better question is, what is "truth doesn't exist" even supposed to mean? Why do humans, even in this day and age, assume they are stating something meaningful just because it's an allowable construct of the language, even when they admit they can't conceive of what it supposedly signifies? The statement is just nonsense, pure and simple, and even making the assumption "truth doesn't exist" just to arrive at a "contradiction" is problematic for that reason.


Non-contradiction by the way, as a principle not a mere law, rests in the concept of identity. What is the case for a self-identical state of affairs cannot also not be the case, as that would violate its identity, and with it the concept itself. "P(a) & not P(a)" is either a nonsense, or a not = a.