What does it mean for something to be "logically possible"?

[untermensche]

A thing is real is it can be found anywhere.

All one needs to do is find one bill or one coin to show money is a real thing.

To show infinity is real only requires showing one real example too.

If you want to compare infinity to something you have to compare it to something like the Tooth Fairy or the Easter Bunny.

Those things are as real as infinity.

From this post and what you have said to me so far, you seem to be saying that something does not exist until it is found. That is absolutely wrong.

I don't think that you believe this.

Infinity is not a thing to be found.

It is an imaginary state of being. A state of going on without end.

You will find infinity out in the world right after you find the Easter Bunny.

 

[untermensche]

A thing is real is it can be found anywhere.

All one needs to do is find one bill or one coin to show money is a real thing.

To show infinity is real only requires showing one real example too.

And yet the infinite number of points between the start of a ruler and the one inch mark hasn't persuaded you.

No, I'm not persuaded by lies and absolute nonsense.

A point is an imaginary mathematical concept. It has no dimension. It is totally imaginary.

It does not exist in the real world.

You will not find a point anywhere in the universe.

Nor will you find the imaginary concept of infinity.

 

[ryan]

From this post and what you have said to me so far, you seem to be saying that something does not exist until it is found. That is absolutely wrong.

I don't think that you believe this.

Infinity is not a thing to be found.

It is an imaginary state of being. A state of going on without end.

You will find infinity out in the world right after you find the Easter Bunny.

Are you saying that something that can not be found can not exist?

 

[bilby]

Infinity is not a thing to be found.

It is an imaginary state of being. A state of going on without end.

You will find infinity out in the world right after you find the Easter Bunny.

Are you saying that something that can not be found can not exist?

http://hitchhikers.wikia.com/wiki/Ravenous_Bugblatter_Beast_of_Traal

The Ravenous Bugblatter Beast of Traal is a vicious wild animal from the planet of Traal, known for its never-ending hunger and its mind-boggling stupidity. The Guide calls the bugblatter the stupidest creature in the entire universe - so profoundly unintelligent that, if you can't see it, it assumes it can't see you.

 

[untermensche]

Infinity is not a thing to be found.

It is an imaginary state of being. A state of going on without end.

You will find infinity out in the world right after you find the Easter Bunny.

Are you saying that something that can not be found can not exist?

I am saying that to assume something is logically possible you first have to show it is physically possible.

Not speculate, but show actual evidence it is possible.

Evidence that this imaginary concept called infinity is physically possible is to show an infinity that actually exists.

But it is so strange I have to say this.

If I told you I knew about an invisible dinosaur that was logically possible but did not have one bit of evidence to support this you would laugh.

 

[ryan]

Are you saying that something that can not be found can not exist?

I am saying that to assume something is logically possible you first have to show it is physically possible.

Not speculate, but show actual evidence it is possible.

Evidence that this imaginary concept called infinity is physically possible is to show an infinity that actually exists.

But it is so strange I have to say this.

If I told you I knew about an invisible dinosaur that was logically possible but did not have one bit of evidence to support this you would laugh.

The universe follows math when there are no other unknowns to consider (even with unknowns the universe still follows math, just not from the math known to humans). And we are closing in on the possible amount of unknowns.

The new model explains what is here and how it got here. If there are no other major "surprises" to add to the unknowns (unexplained observations), the universe will have always been exactly or close to exact to what the model predicts. This leaves it at least possible, not impossible.

So new theories that correct older ones are better theories even though they will probably be corrected in the future, but there is less and less to correct. So why go against the mathematical predictions using the best explanations to date, and even consider them impossible?

 

[Copernicus]

...I am saying that to assume something is logically possible you first have to show it is physically possible...

This contradicts the very definition of the term, which you yourself could have bothered to research. As usual, a good place to start is Wikipedia's description of the meaning of the expression logical possibility:

Logically possibility refers to a proposition which can be the logical consequence of another, based on the axioms of a given system of logic. The logical possibility of a proposition will depend on the system of logic being considered, rather than on the violation of any single rule. Some systems of logic restrict inferences from inconsistent propositions or even allow for true contradictions. Other logical systems have more than two truth-values instead of a binary of such values. However, when talking about logical possibility it is often assumed that the system in question is classical propositional logic. Similarly, the criterion for logical possibility is often based on whether or not a proposition is contradictory and as such is often thought of as the broadest type of possibility.

Logical possibility should be distinguished from other sorts of subjunctive possibilities. But the relationship between modalities (if there is any) is the subject of debate and may depend on how one views logic, as well as the relationship between logic and metaphysics. For example, many philosophers following Saul Kripke have held that discovered identities such as "Hesperus = Phosphorus" are metaphysically necessary because they pick out the same object in all possible worlds where the terms have a referent. However, it is nonetheless logically possible for “Hesperus = Phosphorus” to be false, since denying it doesn't violate a logical rule such as consistency. Other philosophers are of the view that logical possibility is broader than metaphysical possibility, so that anything which is metaphysically possible is also logically possible.

You can, of course, seek to impose your private interpretation on the expression, but language is ultimately public, not private. If others prefer to accept its conventional meaning, then your private substitute does not matter.

 

[untermensche]

I am saying that to assume something is logically possible you first have to show it is physically possible.

Not speculate, but show actual evidence it is possible.

Evidence that this imaginary concept called infinity is physically possible is to show an infinity that actually exists.

But it is so strange I have to say this.

If I told you I knew about an invisible dinosaur that was logically possible but did not have one bit of evidence to support this you would laugh.

The universe follows math when there are no other unknowns to consider (even with unknowns the universe still follows math, just not from the math known to humans). And we are closing in on the possible amount of unknowns.

The new model explains what is here and how it got here. If there are no other major "surprises" to add to the unknowns (unexplained observations), the universe will have always been exactly or close to exact to what the model predicts. This leaves it at least possible, not impossible.

So new theories that correct older ones are better theories even though they will probably be corrected in the future, but there is less and less to correct. So why go against the mathematical predictions using the best explanations to date, and even consider them impossible?

The universe does not "follow math" in any way.

Mathematics is part of what we use to MODEL reality.

Not make a replica of reality.

 

[untermensche]

This contradicts the very definition of the term, which you yourself could have bothered to research. As usual, a good place to start is Wikipedia's description of the meaning of the expression logical possibility:

Logically possibility refers to a proposition which can be the logical consequence of another, based on the axioms of a given system of logic. The logical possibility of a proposition will depend on the system of logic being considered, rather than on the violation of any single rule. Some systems of logic restrict inferences from inconsistent propositions or even allow for true contradictions. Other logical systems have more than two truth-values instead of a binary of such values. However, when talking about logical possibility it is often assumed that the system in question is classical propositional logic. Similarly, the criterion for logical possibility is often based on whether or not a proposition is contradictory and as such is often thought of as the broadest type of possibility.

Logical possibility should be distinguished from other sorts of subjunctive possibilities. But the relationship between modalities (if there is any) is the subject of debate and may depend on how one views logic, as well as the relationship between logic and metaphysics. For example, many philosophers following Saul Kripke have held that discovered identities such as "Hesperus = Phosphorus" are metaphysically necessary because they pick out the same object in all possible worlds where the terms have a referent. However, it is nonetheless logically possible for “Hesperus = Phosphorus” to be false, since denying it doesn't violate a logical rule such as consistency. Other philosophers are of the view that logical possibility is broader than metaphysical possibility, so that anything which is metaphysically possible is also logically possible.

You can, of course, seek to impose your private interpretation on the expression, but language is ultimately public, not private. If others prefer to accept its conventional meaning, then your private substitute does not matter.

You are free to argue. But this is not a rational argument.

It is not rational to claim things that are physically impossible are in any way possible. Including logically possible.

 

[Elixir]

WTF is this thread about? The definition of "possible"?

IMHO, you first have to decide whether or not everything is possible. If not, then anything that doesn't happen was never possible. IOW, the very word possible is nothing more than an expression of ignorance of whether or not it will come to pass. Adding the qualifier "logically" doesn't help the situation.

In an infinite universe/multiverse over infinite time, everything is not only possible, but certain. If the universe (or its duration) is finite, then only that which actually occurs was ever "logically possible" - to say that something that never occurred was possible, is to say nothing more than that we thought it could happen.

There is nothing whatsoever "logical" about something being called possible or impossible, unless this is a psych study wherein we examine the differing opinions of fallible humans regarding specific future events.

Am I missing something?

 

[ryan]

This contradicts the very definition of the term, which you yourself could have bothered to research. As usual, a good place to start is Wikipedia's description of the meaning of the expression logical possibility:

Logically possibility refers to a proposition which can be the logical consequence of another, based on the axioms of a given system of logic. The logical possibility of a proposition will depend on the system of logic being considered, rather than on the violation of any single rule. Some systems of logic restrict inferences from inconsistent propositions or even allow for true contradictions. Other logical systems have more than two truth-values instead of a binary of such values. However, when talking about logical possibility it is often assumed that the system in question is classical propositional logic. Similarly, the criterion for logical possibility is often based on whether or not a proposition is contradictory and as such is often thought of as the broadest type of possibility.

Logical possibility should be distinguished from other sorts of subjunctive possibilities. But the relationship between modalities (if there is any) is the subject of debate and may depend on how one views logic, as well as the relationship between logic and metaphysics. For example, many philosophers following Saul Kripke have held that discovered identities such as "Hesperus = Phosphorus" are metaphysically necessary because they pick out the same object in all possible worlds where the terms have a referent. However, it is nonetheless logically possible for “Hesperus = Phosphorus” to be false, since denying it doesn't violate a logical rule such as consistency. Other philosophers are of the view that logical possibility is broader than metaphysical possibility, so that anything which is metaphysically possible is also logically possible.

You can, of course, seek to impose your private interpretation on the expression, but language is ultimately public, not private. If others prefer to accept its conventional meaning, then your private substitute does not matter.

I think Unter is using a hard-lined scientific realism as a premise without letting anyone know. It's not a terrible premise, and seems to be a popular one in the scientific community (except for some theoretical and mathematical physicists). But it falls apart, IMO, when you have to discount mathematical predictions as impossible.

As you probably know, the string theorists are under attack because string theory is not falsifiable. But their math explains everything; however, it also predicts that anything is possible thus can't be falsified. So ST is impossible with the hard-lined scientific realists.

 

[ryan]

WTF is this thread about? The definition of "possible"?

IMHO, you first have to decide whether or not everything is possible. If not, then anything that doesn't happen was never possible. IOW, the very word possible is nothing more than an expression of ignorance of whether or not it will come to pass. Adding the qualifier "logically" doesn't help the situation.

In an infinite universe/multiverse over infinite time, everything is not only possible, but certain. If the universe (or its duration) is finite, then only that which actually occurs was ever "logically possible" - to say that something that never occurred was possible, is to say nothing more than that we thought it could happen.

There is nothing whatsoever "logical" about something being called possible or impossible, unless this is a psych study wherein we examine the differing opinions of fallible humans regarding specific future events.

Am I missing something?

Yes, you are missing something.

Other than mathematical models and sometimes intuition, typically, anything that is not scientific is an infinitely dismal guess, which mathematically is 0 probability.

Beetles exist because they have been observed. But if I pluck an idea out of presumably an infinite number of choices, say, a beetle that turns into a spider at night between 12:00am and 3:00am, and there is only a finite number of possible kinds of insects on Earth, the shapeshifting beetle must not exist mathematically. (one choice)/(infinite choices) = 0

In an infinite multiverse, this bug exists. But the multiverse is not falsifiable and therefor scientific realists don't except it.

 

[untermensche]

This contradicts the very definition of the term, which you yourself could have bothered to research. As usual, a good place to start is Wikipedia's description of the meaning of the expression logical possibility:



You can, of course, seek to impose your private interpretation on the expression, but language is ultimately public, not private. If others prefer to accept its conventional meaning, then your private substitute does not matter.

I think Unter is using a hard-lined scientific realism as a premise without letting anyone know. It's not a terrible premise, and seems to be a popular one in the scientific community (except for some theoretical and mathematical physicists). But it falls apart, IMO, when you have to discount mathematical predictions as impossible.

As you probably know, the string theorists are under attack because string theory is not falsifiable. But their math explains everything; however, it also predicts that anything is possible thus can't be falsified. So ST is impossible with the hard-lined scientific realists.

This thread is just a response to somebody making the claim that "infinity is logically possible".

I do not believe that.

And I don't think it can be proven to be logically possible.

Because it is not logical to say something that is physically impossible could be possible in any way, especially logically possible.

I think perhaps there is some mutant strain of thought that thinks it is logical to say things that are physically impossible are somehow logically possible.

If your "logic" tells you things that are physically impossible are in some way possible you need a new logic.

 

[ryan]

I think Unter is using a hard-lined scientific realism as a premise without letting anyone know. It's not a terrible premise, and seems to be a popular one in the scientific community (except for some theoretical and mathematical physicists). But it falls apart, IMO, when you have to discount mathematical predictions as impossible.

As you probably know, the string theorists are under attack because string theory is not falsifiable. But their math explains everything; however, it also predicts that anything is possible thus can't be falsified. So ST is impossible with the hard-lined scientific realists.

This thread is just a response to somebody making the claim that "infinity is logically possible".

I do not believe that.

And I don't think it can be proven to be logically possible.

Because it is not logical to say something that is physically impossible could be possible in any way, especially logically possible.

Then you don't understand what logic means or what it is used for. There is nothing illogical about saying that invisible trees grow in an invisible forest even if invisible trees are not physically possible.

Logic, among many other things, is used to organize our thoughts and makes sure we stay consistent with what we are talking about.

 

[untermensche]

This thread is just a response to somebody making the claim that "infinity is logically possible".

I do not believe that.

And I don't think it can be proven to be logically possible.

Because it is not logical to say something that is physically impossible could be possible in any way, especially logically possible.

Then you don't understand what logic means or what it is used for. There is nothing illogical about saying that invisible trees grow in an invisible forest even if invisible trees are not physically possible.

Logic, among many other things, is used to organize our thoughts and makes sure we stay consistent with what we are talking about.

You have some arbitrary and capricious idea about what is and isn't the purpose of logic.

So do I. I say it is a tool to find truth, not folly.

If what you end up with is folly, like believing imaginary things can impinge on reality, you have abandoned logic somewhere.

Sure, imaginary things interacting with other imaginary things can be very useful.

That is mathematics.

But the second you say something can be part of the physical universe you are talking science.

And now evidence for claims is necessary.

 

[Copernicus]

WTF is this thread about? The definition of "possible"?

IMHO, you first have to decide whether or not everything is possible. If not, then anything that doesn't happen was never possible. IOW, the very word possible is nothing more than an expression of ignorance of whether or not it will come to pass. Adding the qualifier "logically" doesn't help the situation.

In an infinite universe/multiverse over infinite time, everything is not only possible, but certain. If the universe (or its duration) is finite, then only that which actually occurs was ever "logically possible" - to say that something that never occurred was possible, is to say nothing more than that we thought it could happen.

There is nothing whatsoever "logical" about something being called possible or impossible, unless this is a psych study wherein we examine the differing opinions of fallible humans regarding specific future events.

Am I missing something?

Well, I would say that there is a distinct difference between "physically possible" and "logically possible". Magic may not be physically possible, but it is certainly logically possible. Logical possibility only means consistency with premises, but the premises can be inconsistent with what we believe plausible in the physical world. A logically consistent conclusion from a set of false premises need not be physically plausible at all. Note the first sentence in the second paragraph of the Wikipedia quote I posted above: "Logical possibility should be distinguished from other sorts of subjunctive possibilities."

Untermensche is just hopelessly wrong, but I think most of us have arrived at that logical conclusion already. So all he can do to keep this ridiculous conversation going is to insist that his critics are not making rational sense. A classic argumentum ad nauseam fallacy.

 

[untermensche]

The illusion of magic is logically possible. Not magic.

 

[ryan]

Then you don't understand what logic means or what it is used for. There is nothing illogical about saying that invisible trees grow in an invisible forest even if invisible trees are not physically possible.

Logic, among many other things, is used to organize our thoughts and makes sure we stay consistent with what we are talking about.

You have some arbitrary and capricious idea about what is and isn't the purpose of logic.

You said, "Because it is not logical to say something that is physically impossible could be possible in any way, especially logically possible.". Assuming invisible trees are physically impossible does not logically mean that they are impossible. They are just impossible physically. They can still exist by logic (but probably not in this universe).

You said "in any way" when you should have added something like "assuming all that exists is physical ...", then I would agree with your quote, and we could move on.

But the second you say something can be part of the physical universe you are talking science.

This is a very hard-lined scientific realist approach. Are you really saying that only science has the final word on all that might exist?

 

[untermensche]

You have some arbitrary and capricious idea about what is and isn't the purpose of logic.

You said, "Because it is not logical to say something that is physically impossible could be possible in any way, especially logically possible.". Assuming invisible trees are physically impossible does not logically mean that they are impossible. They are just impossible physically. They can still exist by logic (but probably not in this universe).

Many imaginary thoughts are possible. But an imaginary thought of an invisible tree is not logic. It is not something arrived at though logic.

And it can't be somehow turned into logic.

And claims of physical possibility are not logic either. They are science.

This is a very hard-lined scientific realist approach. Are you really saying that only science has the final word on all that might exist?

If something actually exists we use science not our imagination to describe it.

 

[Elixir]

...the multiverse is not falsifiable and therefor scientific realists don't except it.

That is the nut of it, right there, IMO.
You are using a rigorous scientific set of analyses wherein not all things that are colloquially "possible" warrant consideration. I would question whether "logically" and "scientifically" are really interchangeable terms. If that's what the OP intended then you're absolutely correct and no further analysis is required - the question is answered. When a scientist says something is possible*, they are saying that there are no known prohibitive factors within that individual scientist's knowledge of the body of scientific (repeatable) observations. When a layperson says the same thing, it's just "I dunno". Yet, there can be disagreements even among scientists as to the possibility of "X".


* If an elderly but distinguished scientist says that something is possible, he is almost certainly right; but if he says that it is impossible, he is very probably wrong.
- Arthur C. Clarke