# This sentence is false.

Night Ripper

Mon 7 Jun, 2010 08:00 am
@guigus,
guigus;174077 wrote:
If it is a truth, then it must be true.

That's like saying that all lottery winners must win the lottery. No, that's false. All lottery winners did win the lottery, that's what makes them lottery winners. But the fact that they won the lottery is still contingent. That particular person didn't have to win, but they did, and now they are a lottery winner. It isn't a necessary truth. It's a contingent truth. You're making a fallacious argument that I've seen made several times before. It's called the modal fallacy.

Emil

Mon 7 Jun, 2010 09:04 am
@Gnostic,
Please learn modal logic, at least learn the modal logic used on the link I gave you before. That wouldn't be too hard (well, maybe for you but for me it was easy).

Then come back after that. I've wasted too much time already to try to explain the modal fallacy to people with no understanding of logic. It is hopeless.

Also, the modal fallacy is not determinism. Stop making things up.

---------- Post added 06-07-2010 at 05:12 PM ----------

Night Ripper;174072 wrote:
1. Necessarily, all true propositions are true, but not 2. all true propositions are necessarily true. There's is an extremely subtle difference that leads a lot of people to commit "the" modal fallacy.

I edited NR's post a little.

In symbols:

1. □(∀x)(Tx→Tx)
2. (∀x)(Tx→□Tx)

The first one is true, the second is not. Arguments that use the second one as a premise commit the modal fallacy. The reason it is called the modal fallacy is because it is the most common modal fallacy (Swartz thinks and I agree).
The cause of it is probably the english language and other similar languages (like danish) where the necessity operator is most commonly placed with the consequent in an if, then sentence. This leads people to believe that it modifies the consequent, not the antecedent. Using symbols avoids this language problem and also being careful with where to place one's necessity operators (and other modal operators for that matter) also helps reduce the problem.

fast

Mon 7 Jun, 2010 11:15 am
@guigus,
[QUOTE=guigus;174077]It is important to forget about propositions because truth is much more than propositions. [/QUOTE]Truth is a proposition, but not every proposition is true. Truth is a true proposition, and every true proposition is true.

guigus

Mon 7 Jun, 2010 06:44 pm
@Night Ripper,
Night Ripper;174201 wrote:
That's like saying that all lottery winners must win the lottery. No, that's false. All lottery winners did win the lottery, that's what makes them lottery winners. But the fact that they won the lottery is still contingent. That particular person didn't have to win, but they did, and now they are a lottery winner. It isn't a necessary truth. It's a contingent truth. You're making a fallacious argument that I've seen made several times before. It's called the modal fallacy.

Sorry, but that is like saying that all lottery winners must HAVE WON the lottery. Because, as you said yourself, they did win the lottery. If a truth is to be a truth, then it must be true: if all lottery winners did win the lottery (if the truth of that fact is indeed a truth), then they must have won the lottery (then this truth must be true). You are having a hard time grasping this just because when you read it you inadvertently replace "any truth" by "some statement," or "a theory," or whatever. But what I am saying is that any TRUTH (which is already a truth) must be true. If it is a truth, then it cannot be untrue, and if it cannot be untrue, then it must be true. I am not talking about something that is true, that it must be so: I am talking about truth itself, that it must be true. To put it in language terms: if it is the noun "truth," then it must accept the adjective "true." The modal fallacy refers to the truth of anything as a necessary truth, or to the truth of whatever is true as a necessary truth. But there is a necessary truth that refers to the truth of anything as a truth. In this case it is whatever is true that is contingent, while its truth is necessary, but not regarding what is true: regarding its truth.

Night Ripper

Mon 7 Jun, 2010 07:24 pm
@guigus,
guigus;174420 wrote:
Sorry, but that is like saying that all lottery winners must HAVE WON the lottery.

But you agree that they weren't lottery winners until they won the lottery, right? So you also agree that they mustn't have won the lottery until they won the lottery. It was only after they won the lottery that you can say they were lottery winners and therefore must have won the lottery. Agreed?

guigus

Mon 7 Jun, 2010 07:43 pm
@Night Ripper,
Night Ripper;174438 wrote:
But you agree that they weren't lottery winners until they won the lottery, right? So you also agree that they mustn't have won the lottery until they won the lottery. It was only after they won the lottery that you can say they were lottery winners and therefore must have won the lottery. Agreed?

I understand what you are saying: they could have got the numbers wrong, it was a contingent event. But this has nothing to do with what I am saying. I am saying that if they did win the lottery, then their having won it must be true. If they did win it, then this event is a truth. And if it is a truth, then it cannot be false. Now answer me: what is an event that cannot be false, other than a necessarily true event? Now careful: this necessity has nothing to do with their chances of winning the lottery, but with our task of considering this event as a truth. The bottom line is: can you imagine a truth that is untrue? I can't. Any truth must be true. When you reconstruct a sequence of events and you establish that something is true, when you come back to it after going on and on you remember: that event must be true, since I have already established so. That's the meaning of "every truth must be true." If you read this as it is written, having two different ocurrencies of the concept of "truth," one as a noun and the other as an adjective, rather than only one ocurrency of truth referring to something else, you will grasp it.

Night Ripper

Mon 7 Jun, 2010 08:25 pm
@guigus,
guigus;174446 wrote:
That's the meaning of "every truth must be true."

Don't you think that's something redundant though? It's like saying that "all white snow is white". Yes that is true, but that doesn't mean that any particular lump of snow couldn't be a different color. If it's white, obviously, it's white. However, whether or not it's white doesn't follow from the truth of "this lump of snow is white". On the contrary, it's whether or not the lump of snow is actually white that dictates the truth or falsity of "this lump of snow is white".

jack phil

Mon 7 Jun, 2010 08:31 pm
@Gnostic,
is it true that a+b=c?

guigus

Mon 7 Jun, 2010 09:00 pm
@Night Ripper,
Night Ripper;174459 wrote:
Don't you think that's something redundant though? It's like saying that "all white snow is white". Yes that is true, but that doesn't mean that any particular lump of snow couldn't be a different color. If it's white, obviously, it's white. However, whether or not it's white doesn't follow from the truth of "this lump of snow is white". On the contrary, it's whether or not the lump of snow is actually white that dictates the truth or falsity of "this lump of snow is white".

Now we are on the same page. You are even advancing my second assertion already: the truth of a being is a true being. Now you got it perfectly: it is when you feel it is redundant that you got it. Every truth must be true. And so what? It doesn't matter: it seems redundant, but this is a "fallacious" feeling. This is in fact a very meaningful piece of information, for one reason: it is undeniable. But it only becomes useful when immediately followed by your last observation, which I rephrase as "the truth of a being is a true being": if any truth were untrue, then it would not be a truth: every truth must be true. And yet, since the truth of a being is a true being, for any truth to be true it must have itself as a truth, which must be different from it. The necessary truth of any truth is a true being. The truth of some guys having won the lottery as an event is their having won the lottery as a true event. Now you see the ungrateful inversion that geopardizes our understanding of all this: it is the fact, the real thing, the external object that is the necessary truth of any truth (we usually think the other way around, as if the ideal truth were the necessary truth of a real object). You said it yourself: it's whether or not the lump of snow is actually white that dictates the truth or falsity of "this lump of snow is white". So, if it is true that the lump of snow is white (a truth), then it must be truly white (the necessary truth of any truth). Indeed, what could be that truth if not a true "whiteness"? Then, the truth of a being (the truth of a white lump of snow) is a true being (a truly white slump of snow). We begin with a seemingly redundant "necessary truth of any truth," seemingly redundant because, at first, we don't know yet what are these "two truths" or how they can be different. It is only when we realize that "the truth of a being is a true being" that we see the difference: the truth of a being is in us, while its necessary truth is a true being outside of us. Thus, when this necessary truth is betrayed, it is because the truth of which it is the necessary truth was not a truth in the first place. But only to keep an accurate record, we have two "moments" here:

1. If any truth were untrue, then it would not be a truth: every truth must be true.

2. And yet, since the truth of a being is a true being, for any truth to be true it must have itself as a truth, which must be different from it.

cluckk

Tue 8 Jun, 2010 01:32 pm
@jack phil,
jack;174462 wrote:
is it true that a+b=c?

fast

Tue 8 Jun, 2010 03:26 pm
@guigus,
[QUOTE=guigus;174446]I understand what you are saying: they could have got the numbers wrong, it was a contingent event. But this has nothing to do with what I am saying. I am saying that if they did win the lottery, then their having won it must be true.[/QUOTE]But that's not how to say what you want to say. Every true proposition is a true proposition, but not every true proposition must be a true proposition. Is, yes; must, no. Not every truth is a necessary truth, for some truths are contingent truths. Only propositions that must be true are necessary truths.

The proposition "the cat is on the mat" is true, but it's not so that it had to be that way, so that it is that way isn't to say it must be, and if it's not the case that it must be, then it's a contingent truth, and if it's a contingent truth, then it's not a necessary truth. So, although the proposition is true, that's not to say it must be true.

You are using "must" in a way that I used to use "must" before I learned not to. If you flip a quarter (that is heads on one side and tails on the other), and if it lands on one or the other, then if you know it didn't land on heads, then you think it must have landed on tails because no other option was available, but it was never the case that you had to flip the quarter, so although it landed on tails, it's not the case that it must have landed on tails --because things could have turned out differently such as you never even flipping the quarter. You should be very cautious not to declare a truth a necessary truth just because something is the way it is.

guigus

Tue 8 Jun, 2010 07:39 pm
@fast,
fast;174825 wrote:
But that's not how to say what you want to say. Every true proposition is a true proposition, but not every true proposition must be a true proposition. Is, yes; must, no. Not every truth is a necessary truth, for some truths are contingent truths. Only propositions that must be true are necessary truths.

The proposition "the cat is on the mat" is true, but it's not so that it had to be that way, so that it is that way isn't to say it must be, and if it's not the case that it must be, then it's a contingent truth, and if it's a contingent truth, then it's not a necessary truth. So, although the proposition is true, that's not to say it must be true.

You are using "must" in a way that I used to use "must" before I learned not to. If you flip a quarter (that is heads on one side and tails on the other), and if it lands on one or the other, then if you know it didn't land on heads, then you think it must have landed on tails because no other option was available, but it was never the case that you had to flip the quarter, so although it landed on tails, it's not the case that it must have landed on tails --because things could have turned out differently such as you never even flipping the quarter. You should be very cautious not to declare a truth a necessary truth just because something is the way it is.

You keep returning to an inverted view of necessity, so let me put it in an way that shows it. When you say that "every truth must be true," you must remember that:

A truth is whatever is true insofar as it is true.

Being true is being the same as whatever makes what is true a truth.

If any truth (a true being) were untrue, then it would not be a truth (either outside or inside my head): every truth (a true being) must be true (first as a being in the world, and then as a truth in my soul).

Which is the modal fallacy. This reading is wrong simply because it puts an ideal truth exclusively outside of me, confusing a truth with the true being that gives it its truth. Now, if you read it the other way around, then you get:

If any truth (in my head) were untrue (as a true being in the world), then it would not be a truth (inside my head): every truth (in my soul) must be true (as a being in the world).

Now there is no fallacy, and you can see the two different truths, despite their identity: a truth in my head must be true outside my head, otherwise it is false.

guigus

Thu 10 Jun, 2010 04:54 am
@guigus,

kennethamy

Thu 10 Jun, 2010 09:11 am
It is simply false that every truth must be true. Counterexample: Obama is president of the United States in 2010, is a truth. But it might be false. And it would be false if McCain had won instead of Obama. What you probably mean is that it must be that every truth is true. But, Emil has already explained why the statement, it must be that every truth is true, is not the same statement as, every truth must be true. The first statement is true. The second statement is clearly false. (See my counterexample above).

guigus

Thu 10 Jun, 2010 10:05 am
@kennethamy,
Taking your own example: Obama is president of the United States in 2010, is a truth. However, it is a truth insofar Obama is indeed president of the United States in 2010. Why? Because every (subjective) truth must be (objectively) true. You are doing a vicious reading of the sentence as: every (objective) truth must be (objectively) true. But your way of reading it leaves no room for any subjective truth, hence leaves no room for any truth at all. In fact, your way of reading the sentence renders it meaningless, for there is no such thing as a truth out there capable of standing as a truth without someone being aware of it: even if there is whatever there is out there, it is only a truth if we know about it.

guigus

Thu 10 Jun, 2010 10:19 am
@kennethamy,
Or take an easier path: read me as "every subjective truth must be objectively true," and try to see the different kind of necessity involved. Then ask yourself if you really can read "a truth" as meaning an objective-only truth. Finally, ask yourself if an objective truth must not be called "a true being," rather then "a truth."

kennethamy

Thu 10 Jun, 2010 10:25 am
Doesn't seem easier at all, since I don't know what you mean. But it is clear that there is a modal confusion when necessarily whatever is true is true, is confused with, whatever is true is necessarily true. Since the former is true, but the latter is false.

kennethamy

Thu 10 Jun, 2010 10:27 am
@kennethamy,
In any case, there are no subjective truths. There are things I believe are true (which may not be true) if that is what you mean.

guigus

Thu 10 Jun, 2010 10:34 am
@kennethamy,
This is the same as to say there are no truths, don't you agree? Truth has two sides: one objective, the other subjective. It cannot exist without any one of them, like a coin cannot exist without one of its sides. The sentence: every truth must be true is only meaningful if you read it as a relation between subjective and objective truth by means of necessity (in the true sense of necessity). Any other reading of this sentence is utterly nonsense.

guigus

Thu 10 Jun, 2010 10:42 am
@kennethamy,
Can't you really see the difference between "a truth" and "a true being"? A truth is your awareness of what is true, and a true being is that is true itself. The sentence "every truth must be true" has both and says that whatever you know that is true must be actually true in the world. This is the very condition of any truth as such.