The Liar Paradox - Stephen Read

Philosopher Stephen Read on the principle of excluded middle, noncontradiction, and Buridan’s ass

[NegativeReferral]

My solution to the liars paradox involves accepting that “I am lying” has two meanings: “I am lying right now, in this very sentence”, and “I have been lying this whole conversation.” Lies can also have a kernel of truth, so it’s possible for the former meaning to be false while the latter is true, though it can also be true in that the statement understates the lies.

[acidic_sloth]

Johnny’s papa: Johnny Johnny?
Johnny: Yes Papa?
Johnny’s papa: Telling lies?
Johnny: Yes Papa.
ErRoR eRrOr ErROr JOHNY.PAPA.EXE has stopped working.

[sparklemuffin]

Bruh I’m watching this at 1 am trying to wrap my head around this

[hardrockwhisker]

I might be wrong, but to me the statement "this sentence is a lie" is an utterance which is empty of any content, therefore it's truth value cannot be judged. Same with uttering a sentence like "this sound is true" - just because we can say something like that, doesn't mean that it contains any meaningful information. Lets look at it another way, if there's a sentence like "two plus two equals five, this sentence is a lie", we would automatically assume that the uttered part which is untrue is "two plus two equals five", because that's the content of this proposition, the latter part essentially is just an evaluation (by the author of that statement) of it's truth value. If you delete the first part, the statement becomes meaningless.

Furthermore, to show how meaningless it is, in that same statement "this sentence is a lie" you can delete everything but the last word, because to say that something is a sentence within a sentence is just a tautology, so what are you left with? The word "lie".

[peterflack]

Thank you, that was really interesting. I'm usually not into A.I. types off things, but its hard to ignore. How you program a computer to lie to you. A priori. > the philosophy of Emanuel Kant. And Russell. Empirical knowledge and synthetic knowledge. Well said friend!

[SiemdeO]

This is something that keeps me awake at night...
no joke... every night I go to bed a hour before i'm planning to sleep,
so I can cogitate...

[chuckgaydos]

"This statement is true" has the same problem but is usually overlooked.

[lamegalectora]

What is the rule of this game he is playing? That you cannot step outside the circle?
I find it amusing that he is so mesmerized by the sound of the words themselves.
The intriguing question is what does this paradox tell us about the tool called language that which we so blindly trust to rule our lives.

[josephs]

Thank you, this was very helpful! Please do not stop providing these valuable vides's.

[alanbunyan]

One approach to solving this issue is to take the view that the supposed self-referentiality of the proposition in question is impossible, for the simple reason that the sentence apparently referenced by the word 'this' does not yet exist: it is IN THE PROCESS of being formed: that is to say, it consists at the moment of reference of nothing more than a grammatical subject ("this") but, as yet lacking any predicate, it has not been formed, i.e. it does not yet exist AS A SENTENCE. It could refer to another sentence which has already been formed, but never to itself. It's a bit like my trying to sell you a car that has not yet been built and asserting '"This car never breaks down", to which you would be entitled to retort that I cannot reasonably make any such claim of something that does not actually exist! To expand a little further, the basic problem here is the fact that a written sentence is an IMPERFECT representation of a spoken sentence: it is flawed in very much the same way that a 2D diagram of a building is flawed as a representation of an actual (3D) building. Since spoken naturally precedes written language (i.e. the second is an attempt to represent/record the first, and not vice-versa) a written sentence, if it were to be completely accurate, would have to contain some mechanism (perhaps, e.g. colour-coding) for indicating that the second word is uttered after the first, the third after the second, and so on. No spoken sentence (except, perhaps for one consisting of a single imperative, such as “Go!”) has ever emerged complete, but is built up word by word over time, and the only thing to which a subject ‘this’ can ever refer is something that already exists at the time of utterance!

[WafferG]

Actually there's three options,
There might not be a wall at all .

[therealswinery]

Let’s say for the sake of discussion that the Liar’s Paradox does indeed prove that the Law of Noncontradiction is false. This would mean that the Law of Noncontradiction could be both true and false, and, since the Law of Noncontradiction is axiomatic, it is. Thus the Liar’s Paradox has no implications whatsoever on the nature of truth, since we could just as easily invoke the truth of the Law of Noncontradiction as we could its falsehood.

[patinho]

Just disallow self-reference-ability in the description of things.

Solved.

This is also how Russell’s paradox is solved, in the set theory axioms, which define what number are.

You just don’t allow it.
And apply the analytical statements only to ‘other’ sentences. Ie the ‘this’ can’t refer to the analytical sentence itself.

Like I say.. solved.

[jasonrafael]

I'm not the best at determining which logical fallacies are taking place, but I feel like comparing a statement's true or falseness to a wall's white or non-whiteness is a false equivalence, or maybe a non-sequitur..

Yes, if you limit the color spectrum to two options to say a wall is either white or not white, yes, only those two options are available. But in reality, the wall can be any option of colors. So there never really was only 2 options, you just limited it to those two options.

Likewise, must a statement ALWAYS be either true or false? And, by the way, saying a statement is either true or untrue is just the same as true or false... "This statement is false".. What if it is just a paradoxical statement, and that's the third option, and we don't have to try so hard to make sense of it? What if it's just a nonsense statement?

"box rained hill car there over"

Is that statement true or false? Neither.. it's just a nonsense combination of words.

[ABC-ytnq]

This purported paradox proceeds on the false premise that the evaluation of something can be contained within that thing being evaluated. 

It appears to be impossible for the evaluation of something - let's call it X - to also be contained in that X. The evaluation of X changes the value of X from X to X + [Evaluation of X]. Prima facie these values are not and can never be equal. 

Imagine X can only be either True or False. We know some things about X, but not whether or not it is T or F. To learn that will add information to and expand our definition of X, changing it from X to either X+T or X+F.

This appears to be similar to the observer effect, which alters the results of the double slit experiment by the act of observation of sub-atomic particles, which previously were waves, by collapsing the wave function into the observed particles. 

Thus, in order to evaluate X, and not X + [Evaluation of X], the evaluator of X must be completely separate from and independent of X and must not affect the value of X by the act of evaluation. This is impossible when observing sub-atomic particles because of the workings of quantum mechanics, but it is possible in larger, grosser information systems. Symbology - specifically written language - is such a system.

The sentence that is the target of evaluation for Truth or Falsity is an essential part of the communication but is missing. This appears similar to asking someone to calculate the square root of ... and then not telling them the number you want them to calculate the square root of. Without the separate sentence to be evaluated being set out, the word combination "This sentence is false" is gibberish with zero information value.

The sentence "This sentence is false" must by necessity be an evaluation of a separate and independent sentence which was communicated, in full, at some point in time prior to the evaluation.

The only proper answer to the Liar's Paradox of "Is this sentence false?" is, "Which specific sentence are you referring to?"

[V_Rosez]

If a Liar says hes Lying is he telling the truth

[matthewthompson]

This has potential to be either true or untrue based on how one thinks about what is meant by "lying". Unlike an action verb expressed in the world (i.e. "painting", "jumping", "laughing") lying is similar to words like "thinking" or "dreaming". It is content of the mind and therefore rather unknowable to anyone but the doer of that action. If I say that I am lying, you can either take it at face value or not, just like "I am thinking". It really is a rather silly "paradox".

[JascLr]

Paused video to say this...did not watch to end. But her eis my thinking.
"What I am saying is a lie."
Typical issue: well...if it is a lie, then what they are saying is true! Therefore not a lie! But...that means it isn't true...so therefore it is a lie...*exploding brain noises*.
My answer. Yes. What you are saying is a lie (is untrue).
Because if you are lying about I being a lie...it is still a lie, by saying a lie isn't a lie, you are lying about it being a lie. Therefore it is still a lie.
But if you are telling the truth, that it is a lie, then it is still a lie. You have admitted to lying by saying such.
But I am probably wrong...

[peterflack]

He said "pee". Its probably pronounced PI. Or in other words the infinite number. Golden ratio. A perfect circle example indescribable. An indescribable utterance.

[hanzhou]

here are six points I've summarized from this video: