We're just repeating ourselves here. I've given you 2 clear definitions and use cases of the words "true" & "false". You seemingly acknowledge what I'm saying then you go back and repeat your previous talking points.

So to repeat myself: "What is" is not true. "What is" is not truth. "What is" is not "the Truth". Etc. "What is" simply is. It is our sentences describing "what is" that are true or false.

If true refers to the property of sentences and propositions, isn't a true sentence "what is" while a false sentence is "what is not"? — Philosophim

Again - no! You keep equating our sentences with "what is". True sentences describe "what is" - they are not equivalent to "what is".

My challenge for you is to see if you can come up with a context of truth that doesn't contain 'what is' at its base, — Philosophim

Notice that you used the word "contain" - this is yet another poetic metaphor. A true sentence does not contain "what is" - it describes "what is".

Anyway, I'll give you the last word.

Hi EricH, I wanted to say first of all I love your light hearted style of posting, much appreciated. :) — Philosophim

I'll never understand the level of invective out here. I mean let's face it - we're all a bunch of eccentric cranks out here. Let's have some fun, but don't take it too seriously.

As I use them, the words “true” and “false” are adjectives which describe properties of statements/propositions. The words “truth” and “falsehood” are the noun forms of the adjectives; they identify statements/propositions that have the property of being true/false. — EricH
I agree with this. — Philosophim

But you're gonna disagree in a moment.

1) Statements are true if they accurately (or as accurately as possible) describe the real world (AKA reality, the universe, existence, what is, etc) This is commonly referred to as the Correspondence Theory of Truth.
2) Mathematical/logical propositions are true if they follow the rules of a particular mathematical/logical framework -e.g. Peano Arithmetic. Any particular proposition can be true in one mathematical system and false in another. — EricH
No objection here either. What's important here is that you have clearly established that we are talking about truth as a state of reality, not a belief or something we know. — Philosophim

Suffering succotash! You seemingly just agreed with me above that the word "truth" identifies statements that are true. So I most definitely am not talking about "truth as a state of reality". To repeat, I am talking about the word "truth" as a property of sentences/propositions.

You appear to be using the word "truth" in a completely different way here. Now there's nothing wrong with this - but if so then you need to give that definition and show how it works semantically in specific contexts.

================

Mathematics is not true by virtue of being. Mathematical statements/propositions are true or false within the rules/context of a particular framework, but the words “true” and “false” do not apply to the field of mathematics (the manipulation of numbers and symbols). Mathematics is neither true not false. — EricH

Almost, we just have to clarify the context. Is it true that 1 captures 'an identity'? — Philosophim

I don't know what you mean by 'an identity'.

Is it true that 1+1=2? — Philosophim

I can only repeat myself here. If you have one apple in your right hand and one in your left, you have two apples. etc, etc. But "1+1=2" is only true within certain mathematical frameworks (e..g. Peano Arithmetic) and it is only true because it can be derived using the axioms and rules of the framework. There are other mathematical frameworks in which it may not be the case.

Is it a belief, or is it a known truth? — Philosophim

Aargh again. It is neither..

After all, we just don't believe that 1+1=2, we know that 1+1=2. — Philosophim

Sigh - we know no such thing.

1+1=3 would be false, but this is because we know it to be false. — Philosophim

Again we know no such thing. What we do know is that by applying the axioms of Peano Arithmetic we can prove that "1+1=3" is false - but again this is only the case within Peano Arithmetic.

================

Any discussion of true and false must involve the context of belief and knowledge in some sense of the discussion — Philosophim

You spend a lot of time on belief/knowledge, but this is [metaphor alert!] a side show. Of course belief and knowledge are legitimate and important topics of conversation, but they do not affect the semantics of the words "true" and "false". If we say
I believe P.
I know P.
where P is a sentence/proposition about reality/existence/what is/the universe/etc? It is P which is true or false. The words "belief" and "know" are used to indicate the speaker's attitude/assessment/evaluation/judgement/confidence in/etc of the accuracy of P.

==================

Truth is, "What is". — Philosophim

As I said in my first response, this is not a definition, it is a poetic metaphor. The universe/existence/what is/everything that is the case/reality/etc is neither true not false - it simply "is". it is our statements about the universe/existence/what is/everything that is the case/reality/etc that are true or false.

Interestingly enough, @Arcane Sandwich seems to agree with you on this point.

Truth = Reality

What it means:
It mea[n]s that Truth is identical to Reality.

Good enough? — Arcane Sandwich

==================
Summary - I'm doubting that this conversation will be productive moving forward. I'm pretty much repeating the previous points I made - and you seem to be mostly repeating your points. But who knows. I've presented a pretty sound case that there are two working definitions/usages of the adjectives "true" and "false" - and their noun equivalents. You seem to be suggesting that there is a third definition/usage, but so far I'm not seeing anything I can sink my [metaphor alert!] philosophical teeth into. But if you can present a clear and explicit definition and the context(s) under which your definition functions, I'll definitely check it out and try to respond.

Another very delayed response here . . .

We’re taking past one another. I will try to clarify. I suspect that I will fail in communicating, but I’ll try again.

To recap what I said, I am attempting to make a very narrow point about the semantics of the words “true”, “truth” “false”, and “falsehood” (and any synonyms).

As I use them, the words “true” and “false” are adjectives which describe properties of statements/propositions. The words “truth” and “falsehood” are the noun forms of the adjectives; they identify statements/propositions that have the property of being true/false. My position is that there are two uses of these words that work - i.e. that make semantic sense. Any discussion of wisdom, knowledge, belief etc is a separate topic which has no bearing on the semantics of the word “truth”.

1) Statements are true if they accurately (or as accurately as possible) describe the real world (AKA reality, the universe, existence, what is, etc) This is commonly referred to as the Correspondence Theory of Truth.
2) Mathematical/logical propositions are true if they follow the rules of a particular mathematical/logical framework -e.g. Peano Arithmetic. Any particular proposition can be true in one mathematical system and false in another.

With that in mind . . .

Basically we use true for, "True as I know/believe it" and "True despite my knowledge or beliefs" — Philosophim

I read this and am reminded of the old joke about The Lone Ranger and Tonto (it’s considered a bit racist these days).

Anyway, maybe this is how you use the word true, but I suspect that the majority of folks out here would disagree with this.

Basically we use true for, "True as I know/believe it" — Philosophim

For purposes of this discussion I will take it that this is analogous to The Correspondence Theory of Truth (my first definition/usage of the word “truth”). So we agree on this usage.

“1+1=2” is only true within the context of a mathematical framework - e.g. Peano Arithmetic. — EricH
Agreed. Kant came up with two terms that attempted to capture these differences. Analytic knowledge is true by virtue of being, — Philosophim

Aargh! No! I am not qualified (and have no interest) in discussing Kant, but I am confident in saying that Peano Arithmetic (in fact all mathematics) is a human invention in which we manipulate symbols within specific rules. Mathematics is not true by virtue of being. Mathematical statements/propositions are true or false within the rules/context of a particular framework, but the words “true” and “false” do not apply to the field of mathematics (the manipulation of numbers and symbols). Mathematics is neither true not false.

No, I actually was using it as another synonym. — Philosophim

If you are using the word “truth” as a synonym for “existence” then the following sentence is semantically correct:

“According to our best scientific knowledge, truth came into existence 13.8 billion years ago”

This is patently absurd (at least it looks that way to me). I am humbly requesting that you refrain from using the word "truth" in this fashion.. It serves no syntactical or semantic purpose and only makes communication massively confusing.

Perhaps the word 'truth' has becomes such a broadly applied word in culture that it is difficult to use it in a distinct and clear context. The problem is that if we don't lock it in to clear and distinct contexts, then it becomes what I like to call a 'wiggle word'. — Philosophim

Absolutely! That is exactly what you are doing here - you are giving the word “truth” an additional context that converts it into a “wiggle word”. There are already two clear & distinct contexts in which we can use the word “truth”, there’s no compelling need to give it this third definition.

Belief, knowledge and truth are not the same thing. — Philosophim

I would consider “knowledge” and “belief” to be wiggle words - and as I stated they have nothing to do with the point I am trying to communicate. There are endless discussions out here on TPF debating the meanings/usages of these words - and it seems like no two people can agree.

As long as we remember that belief and knowledge are assessments of what is true, and not 'Truth' itself, its a bit easier to sort out a solid meaning of truth that more easily avoids being a wiggle word. — Philosophim

I’m not sure what you’re saying here. You’ve capitalized ’Truth’. Are you asserting that there is this, umm, thing out there called Truth? If so, then you’ve introduced yet a 4th usage of the word “truth” and I strenuously disagree. There ain’t no such thing as “Truth itself”. Or perhaps you are opposed to using the word “Truth” in this way? In which case I agree.

Anyway, just to re-iterate. There are two semantically consistent ways of using the word “truth”. The words “knowledge” and “belief” do not factor into these definitions/usages.

You haven't changed my mind about the quality of that particular poem, but I'll take the praise. Thanks!

Very belated response here . . .

I think we’d all agree that words can have different meanings depending on the context. When I use the words “true” or “truth” they have one of two different meanings.

"A true statement is about something concrete, and corresponds to reality." — Philosophim

That is one of the meanings I use. When a person in a USA court swears to tell the truth they are saying that their sentences will correspond to reality. An important corollary to this is that the words “true” and “truth” require the words “false” and “falsehood” (or similar). We need some semantic way to express that a statement about something concrete is not true.

"1+1=2" — Philosophim

At the risk of going on a tangent, this statement is true - but the context is different. If I have one apple in my left hand and one in my right I have two apples. If I have an apple in one hand and an orange in the other I have two pieces of fruit. Etc. But once we say “1+1=2” we are no longer talking about something concrete - we are doing math - we are manipulating symbols. “1+1=2” is only true within the context of a mathematical framework - e.g. Peano Arithmetic. And - as previously - we need some method to state that a particular mathematical statement is not true.

So far, so good.

Truth is what simply is. — Philosophim

Ii could be mistaken but I don’t think you’re saying that “what simply is” is simply another definition/synonym for the word “truth" (or visa-versa). I don’t think you’re saying that we can use the word “truth” in place of using the phrase “what simply is”. If that were the case then there are much better words - “reality”, “the universe”, existence”, etc - which do not have any additional implication.

So from my perspective it seems that you are trying to create a third context in which the words “truth” and “false” have specific meanings - but how this works is not clear to me. Just e.g., how does “falsehood” work in your context? Would you say “Falsehood is what simply is not”?”

I’m guessing (and again I could be wrong) that you are trying to express a more encompassing philosophical concept. You may be onto something here (not me to judge). But your usage strikes me more as poetry. Here I’ll compose a short poem:

What Is - by EricH

Truth is the sky is blue
Truth is my love for you
Truth is not a miss
Truth is what simply is.

Not a particularly good poem - pretty pathetic actually.

the proposition "five legged blue creatures that breathe fire freely roam in Cyprus" isn't [truth apt]. — RussellA

This is sort of nit-picking, but I consider this sentence to be truth apt. After all, I can envision some evil super genius genetically engineering such creatures and setting them loose on Cyprus. Of course it's false.

"The non-existent apple threw the square root of the Eiffel Tower"

Now that is most definitely not truth apt.

Does it mean "therefore" has some logical significance in the statement and all statements? — Corvus

There are likely an infinite number of sentences (or certainly a very large number) that could contain the word "therefore", so I can't comment on how it would work in all sentences. But I would agree that typically the word "therefore" is used to indicate that there is a linkage between the other components of the sentence (or perhaps a previous sentence). I googled synonyms for "therefore" - "accordingly", "hence", "thus" "consequently" & "ergo" all seem to have similar usages (with some subtleties in emphasis and style.)

When you say, "I think therefore the Moon exists. ", doesn't sound quite logical or convincingly meaningful or true, than "I think therefore I am.". What do you make of this? — Corvus

We can construct an infinite number of sentences (or certainly a very large number) that are grammatically correct/sound but which have no semantic meaning. "The capital of France is Paris therefore zebras have purple hexagons for camouflage". "Quadruplicity drinks procrastination" "Colorless green ideas sleep furiously" etc

"I think I am" sounds like I am guessing I exist. — Corvus

Indeed, yes.

"I think therefore I am." indicates "I think" is the precondition or necessary foundation for "I exist". — Corvus

I would put it a bit differently, but this is fine.

So how can the same "I think" imply guessing, and also the solid reasoned precondition for the existence? — Corvus

Because context matters. The same word or phrase can have wildly different meanings depnding on the full context on which they appear.

Or are they different "I think"? — Corvus

They are different. The additional word "therefore" changes the meaning of the full sentence exactly as you just described.

There’s no need for a clarifying statement as it is obvious by the plain language reading. I’m a plain language person. As an aside, I can’t remember the exact quote but didn’t someone once say something to the effect that philosophy takes things that are obvious and tries to make them seem more complicated than they are?

There doesn't seem to be difference between saying,
1) The oak tree is standing there. and
2) You I think that the oak tree is standing there. — Corvus

To my way of thinking these are very different things. #2 implies that the speaker is not certain. I.e., there is an implied "But I could be wrong" that follows #2.

[Edit] Now that I've thought about this some more, it seems to me that the sentences are even more different.
#1 is not expressing a thought, it is a proposition that is either true or false via the Correspondence Theory of Truth.
#2 is a speaker expressing a proposition which they have (at least some) confidence that it is true.

All due respect, that is a red herring. It is not necessary to understand set theory to understand such basic facts as 2+2=4, they are logically necessary within arithmetic.. — Wayfarer

To the best of my knowledge that's simply not the case - at least with regards to arithmetic. If you have two apples in one hand and two apples in the other you have 4 apples. If you have two apples in one hand and two oranges in the other you have four pieces of fruit. Etc. But to say 2 + 2 = 4 is logically necessary within arithmetic is simply not the case - it relies on the rules of arithmetic - which are not logically necessary.

Is anything within math is logically necessary? People much smarter than anyone here on TPF have been studying and analyzing & theorizing about this for thousands of years - and as far as I'm aware there is still no definitive answer to these deep mysteries.

BTW - just to be clear, I am not taking a stand on whether there are such things as necessary truths - I'm simply saying that 2 + 2 = 4 is not one. That's why I suggest you need a different example - is all.

Good luck with your endeavors.

The point about necessary being is that it needs no explanation. It is the terminus of explanation for all question about 'why is that the case?' A trivial example is the case of a simple arithmetical equation, what is the sum of two plus two? The answer of course is 'four' and there is no point in asking why it is. Asking "why is 2 + 2 = 4?" misconstrues the nature of necessity. — Wayfarer

At the risk of picking on a minor point, I think you need a better example of something that needs no explanation. There is nothing "necessary" about 2 + 2 = 4. In fact this depends on a number of more basic assumptions (axioms).

If John is in Paris is claimed as the axiom or fact in this proof above, then it gives a logical implication that John is not anywhere in Japan. — Corvus

Again, no one is disagreeing with this.

It sounds like you have never heard of "reductio ad absurdum" in Logical Proof. — Corvus

Of course - but reductio ad absurdum is not part of propositional logic.

I'll try one more time. Once you say P->Q, ~P, ~Q you are (at a minimum) in the world of propositional logic and your proof must follow the rules of propositional logic.

If P is of the form "X has property Y"?

~P is not "X has property Z"

~P is "X does not have property Y"

I can't make it any clearer. And now I'll give you the last word.

I've been very reluctant to respond to you given your desire not to continue the conversation, but the thing is - we're on the same side regarding the OP. I agree with you that PSR is nonsensical. And I also feel that maybe I did not explain things well enough. So please take what I'm saying here in the spirit of constructive criticism - I'm not trying to belittle you.

So first of all, of course if John is in Paris then he is not in Japan. As my kids would say - "Duh dad!". You don't need any premises or propositional logic or truth tables to figure this out. All you need is common sense and some rudimentary geography.

But once you say this:

P->Q
~P
~Q

you are now using (at least) propositional logic which has a very specific set of rules - and if you do not follow those rules you will get called out. Some basic rules are:

P = P
~P = ~P

You are saying that P is "John is in Tokyo". No problem there. But then ~P is "John is not in Tokyo".

Saying that "John is in Paris" obviously contradicts P by common sense, but it is not the same thing as ~P. If this were the case (which it isn't) then you would have an infinite number of different ~Ps that contradict each other:

"John is in Paris" is <> "John is in Oslo"
which yields
~P <> ~P

which is obviously wrong.

If "John is in Tokyo" then "John is in Japan", but if "John is not in Tokyo" then John could be some other place in Japan.

I hope you find this helpful.

Good catch Tim. I would put it slightly differently - there are missing steps/facts in Corvus' "logic":

P -> Q
If John is in Tokyo, then John is in Japan.
R
John is in Paris (not in Tokyo). <=== A fact from real life situation.
S
Paris is not in Japan <=== Another fact from real life situation.
R & S ->~Q
Therefore John is not in Japan.

P -> Q
R
S
R & S->~Q
Therefore ~Q — Corvus

P is irrelevant to getting ~Q. Of course this is all loosey-goosey and not formal 1st order logic

I am a millionaire totally and solely dependent on the fact of the antecedent "If I win the lottery jackpot". — Corvus

In which case, Q would have been proved without the proof process. — Corvus

I thought I was clear, obviously not. I've bolded the key phrase. As you acknowledged, this is simply not the case - your being a millionaire is clearly NOT dependent on winning the lottery. For your example to work, it needs to be re-phrased. I can think of two options:

1 - Add an additional qualifier: If I was not previously a millionaire, then etc etc . .
OR
2 - Get rid of the "totally and solely dependent". E.g., If I win the lottery jackpot then I will be a millionaire

And without which, you have left the logic behind, not having proved ~Q, but simply having asserted it. — tim wood

.I am a millionaire totally and solely dependent on the fact of the antecedent "If I win the lottery jackpot". — Corvus

You could already be a millionaire prior to the lottery drawing.

Words have meanings/usages - and your inconsistent statements render your arguments meaningless. Just to give a contrast, I disagree with @Bob Ross but his position is clearly articulated and understandable. I'll give you the last word if you want.

I haven’t contradicted myself, or at least you have not shown it. — NOS4A2

Sigh. I'm a glutton for punishment. I'll try one more time. Here are two statements from you:

No measurable property called “personhood” appears or disappears in any given human being. — NOS4A2

Humans have the capacity to speak a language at some point in their lives. — NOS4A2

The second statement clearly contradicts the first. The second statement says that there IS a measurable property that appears (and may disappear) in any human being - namely the capacity to speak a language.

And again, you do not make any distinction between the terms "person/personhood", "human", or "human being" - so you cannot define your way out of this contradiction.

I don't know any way to make this any clearer.

If I take your position seriously, then we cannot say that a dog fossil is a dog fossil. — Bob Ross

A corpse of a dog is a hunk of meat that used to be a dog until it died - it is no longer a dog. A dog fossil is a fossil of an animal that was a dog when it was alive.

Do you consider a brain dead individual on life support to be a member of the human species?
Is he some other species? I’d love to hear that argument. — NOS4A2

Does your reasoning rely on some distinction between “person” & “human being”?
I don’t distinguish the two, personally. — NOS4A2

It's really hard to follow what you're saying since you keep changing your terminology.
You have repeatedly stated that you do not see any difference between being a person and being a human being - so I was using your terminology. I'm assuming here that when you say "human being" then this entails being a member of the human species.

No measurable property called “personhood” appears or disappears in any given human being. Therefor no one can pick and choose with any certainty when one is or isn’t a person. — NOS4A2

Humans have the capacity to speak a language at some point in their lives. — NOS4A2

You're all over the map here contradicting yourself. Is there a distinction between personhood (being a person) and being a human being (i.e. being a member of the human species?) Yes or no?

And to answer your question, I consider a brain dead body on life support to be a hunk of meat.

I'm amused by this little side discussion about necrophilia. Let me offer a quick personal observation. My father bequeathed his corpse to medical science. This was a noble gesture. I haven't decided yet what to do with my corpse - I vacillate between my dad's decision, or donating body parts, or doing one of these environmentally sound burials. But either way it is my choice.

So if a person decides that they wanted to charge any necrophiliacs out there to, umm, do their thing on their corpse - say $100,000 a pop - and then donate that money to a worthy charity? Apart from being really bizarre (in my opinion) I'm guessing that would be morally/ethically OK.

So what happens if a person does not specify what to do with their corpse? That's up to the estate. Should the estate be allowed to rent the corpse out to necrophiliacs? I can't give a definitive answer but my sense of things is that unless the person expressed some desire in that regard then I would disapprove. Of course there is always the laws of the land to take into account as well.

NOS conflates person & human being so I was working within that framework. There have been so many posts flying back and forth that it is hard to follow, but I'll try to work within your framework. Anyway, with that in mind we still disagree. I do not consider a dead dog to be a dog. This is not "uncontroversially true" - it is opinion. I consider a dead dog to be a hunk of meat that used to be a dog. Same thing applies to Homo Sapiens.

Yes; and that is uncontroversially true. — Bob Ross

Firstly this is not "uncontroversially true" - it is an opinion. Many people disagree with you.

And on that note we will have to agree to disagree. I understand and respect your principled opinion. But I (along with many other people) consider a brain dead body to be a hunk of meat, not a person.

Still circling. You have not yet defined the characteristics that define a human person.

Now it’s a human person. First it was a human being, then it was a human animal, next it’s a human person. — NOS4A2

Your replies are becoming even more incoherent. Here's what you said a few days ago:

Does your reasoning rely on some distinction between “person” & “human being”?
I don’t distinguish the two, personally. — NOS4A2

I'll try one more time. What are the characteristics that describe a human person / human being?

A genetically unique individual which has the genes of a human is, standardly, considered a member of the human species. I don’t see anything circular here. — Bob Ross

Do you consider a brain dead individual on life support to be a member of the human species?

Still circling. You have not yet defined the characteristics that define a human person.

Being a human animal is all that is required to be a member of the human species. — NOS4A2

You're still going around in circles. How do we identify whether a collection of cells and protoplasm is an animal - let alone a human animal. Why is a severed limb not an animal (I agree that it isn't, but you have not provided a coherent explanation)?

When, for you, does an organism become a member of its species? Anything you say is going to be utterly arbitrary, if it is not conception. — Bob Ross

This is still circular logic. What makes one collection of cells and protoplasm a member of the human species? It is not merely the presence of a particular set of genes/chromosomes - there must be something else.

This is a textbook example of circular reasoning.

You are saying (or at least it appears that way) that a zygote is a human being because it turns into a human being. But unless you can give some definition/explanation of how to identify a human being this reasoning is circular and vacuous. And as you said elsewhere

No measurable property called “personhood” appears or disappears in any given human being. Therefor no one can pick and choose with any certainty when one is or isn’t a person. — NOS4A2

Does your reasoning rely on some distinction between “person” & “human being”?

A zygote is a very brief stage of development of an individual human organism, — NOS4A2

No measurable property called “personhood” appears or disappears in any given human being. Therefor no one can pick and choose with any certainty when one is or isn’t a person. — NOS4A2

I can't figure out your terminology . What do you mean when you use the terms "personhood" vs. "human organism / human being"

A fertilized egg is a human being because it is the earliest stage of development of a completely separate organism of the human species. — Bob Ross

Maybe I'm missing some context and/or not following you, but this seems to be circular reasoning. You seem to be saying that a zygote is a human being because it will develop into a human being. But this begs the question - how do we define a human being? Or put slightly differently, what are the essential qualities of a particular collection of cells and protoplasm that allow us to call it human?

Also (at the risk of going on a tangent) - do you make any distinction between "human being" and "person". In my mind these are synonyms?

I don't understand your reply. You say there is no means to determine personhood, yet (if I follow you correctly) you agree that a country's legal system has to make that decision.

No measurable property called “personhood” appears or disappears in any given human being. Therefor no one can pick and choose with any certainty when one is or isn’t a person. — NOS4A2

But that's the whole point of this particular line of discussion. The laws have to make that distinction - there needs to be some means to determine whether any given collection of cells and protoplasm is legally a person or not.

I’m continually impressed with how patient you are in these discussions.

I'm not following you. When you use the word "they"? Who are you referring to?

I’m coming in late here, so apologies in advance if this has already been discussed somewhere in the preceding 14 pages - but at the risk of adding yet another dimension to this good discussion it should be pointed out that there is already a real life aspect here: namely self driving cars. There are numerous hypothetical situations, here’s one:

You`re alone in a self driving car going 55 mph down a two lane road. All of a sudden another car filled with people pulls out in front of you and stalls (maybe it’s driven by a person or maybe there’s a mechanical failure). We’ll assume the technology is sophisticated enough to tell that there is more than one person in the other car. Your self driving car cannot swerve around it because there’s another car coming the other way. The only options are to plough into the stalled car or or to swerve off the road down a steep hill and over a cliff. Your self driving car has air bags and other safety equipment so if your car crashes into the side of the stalled car you will survive with minor injuries but the occupants of the other car will be seriously injured and possibly die. On the other hand if your self driving car chooses to serve off the road then likely you will die.

How should the programmers of the self driving car handle this situation? Beats me.

Therefore, how can any one say that "this sentence contains five words" is true if no one knows which sentence is being referred to? — RussellA

Just to repeat:

"this sentence contains five words" is true IFF this sentence contains five words — RussellA

This sentence has five words. Not true? — TonesInDeepFreeze
Yes, true. — RussellA — EricH

Which sentence were you referring to when you made these statements?

it is not correct to say that the sentence "this sentence contains five words" is true because it contains five words. — RussellA

"this sentence contains five words" is true IFF this sentence contains five words, not because the sentence "this sentence contains five words" contains five words. — RussellA

This sentence has five words. Not true? — TonesInDeepFreeze
Yes, true. — RussellA

The words "has" and "contain" have identical meaning in the context of this discussion.

Conclusion? "This sentence contains five words" is true. QED