# Thread: If I can imagine it, it's logically possible?

1. ## If I can imagine it, it's logically possible?

If I can imagine it, it's logically possible.

Test: square circle? No, I can't.

Test: The Earth is flat? Yes, I can.

Test: God? Well, I sure can imagine something, but I wouldn't say it looks like God. So, me, I can't.

OK, it's good to me, if I can imagine it, it's logically possible.
EB

2. Originally Posted by Speakpigeon
If I can imagine it, it's logically possible.

Test: square circle? No, I can't.

Test: The Earth is flat? Yes, I can.

Test: God? Well, I sure can imagine something, but I wouldn't say it looks like God. So, me, I can't.

OK, it's good to me, if I can imagine it, it's logically possible.
EB
There are concepts that you can imagine - or at least think you can imagine - which aren't logically possible.

Can you imagine squaring the circle? Lots of mathematicians thought they could until it was proven to be impossible.

https://en.wikipedia.org/wiki/Squaring_the_circle

Can you imagine a program that always perfectly predicts whether a given program will halt on a given input? Probably you do think you can imagine that, but it's not logically possible, as Turing proved.

https://en.wikipedia.org/wiki/Halting_problem

Can you imagine an anti-virus program that repels every computer virus? That's also impossible! (I doubt that Wikipedia has an entry for this, but there is a proof in my computer security textbook.)

Can you imagine a set of all sets that don't include themselves? Probably so, but it's not logically possible for such a set to exist.

Can you imagine a consistent geometry that doesn't obey Euclid's axioms? Nobody could until non-Euclidean geometry was discovered.

https://en.wikipedia.org/wiki/Non-Euclidean_geometry

This is also very subjective. You say you cannot imagine God, but plenty of people think they can. Whose imagination is the standard for logical possibility?

3. I should have defined my terminology:

Imagine
1. To form a mental picture or image of: imagined a better life abroad.
I always forgot most people are very nearly illiterate.

What you imagine is never God or Santa Claus or a square circle.

Rather, you imagine something and you call that God, Santa Claus or a square circle, or even more often you say you imagine without actually doing it.

And, my claim relates to what you imagine as you imagine it. It's easy to imagine an old man dressed in a red coat and call than imagining Santa Claus. Right. Who is going to care?

Still, it is logically possible that there is an old man dressed in a red coat. So, you see, if I can imagine it, it's a logical possibility. Right. We all know that.

Try to imagine a new society, in a realistic way. I don't think anyone can do that beyond a sketch. Try imagining a square circle in a realistic way. No way. God? LOL.

So, sure, whatever you're able to imagine, it's a logical possibility (assuming you're not insane, not a zombie, not dead etc.). But try to look honestly at what it is exactly you imagine. Any idiot who did a little creative work knows how hard it is to imagine something you never had the experience of. Try to write a novel, a good example of imagining possible human relationships. Realistic novels that are also imaginative are very few. Most novels are essentially a rehash of experience, which is the easy route to logical possibility because you know it very nearly already exists. Like drawing what you see.
EB

4. Originally Posted by Torin
There are concepts that you can imagine - or at least think you can imagine - which aren't logically possible.
You can imagine or you can't. I'm not talking about can't. If you can, then it's a logical possibility.

Originally Posted by Torin
Can you imagine squaring the circle? Lots of mathematicians thought they could until it was proven to be impossible.
No they never imagined a square circle.

Some people believed a square circle might be possible. They even have spent their whole like trying to prove their belief true. But not once did they imagine a square circle.

Originally Posted by Torin
Can you imagine a program that always perfectly predicts whether a given program will halt on a given input? Probably you do think you can imagine that, but it's not logically possible, as Turing proved.
You see I stopped at "perfectly". I can't imagine "perfectly". Looking at the rest, well, no. I did a lot of programmation for my job and I know you don't imagine a programme. You write it. Same for all complex tasks. Management, military operations, sending men on the Moon.

Still, some people will do the hard job of imagining complex things. If they do that, then it's logically possibly. However, what is logically possible is exactly what they imagined, not necessarily what they say they have imagined. And most of the time, what people imagine is not realistic and never get to be realised. In effect, what people imagine is usually not realisable in practice. But, it will still be logically possible.

Originally Posted by Torin
Can you imagine an anti-virus program that repels every computer virus? That's also impossible! (I doubt that Wikipedia has an entry for this, but there is a proof in my computer security textbook.)
You can't imagine that realistically. I don't think anyone sane would believe they can but that would be irrelevant. You can't imagine it. Whatever anyone did imagine was logically possible, though. But, what they imagine wouldn't be realisable. It wouldn't work.

Originally Posted by Torin
Can you imagine a set of all sets that don't include themselves? Probably so, but it's not logically possible for such a set to exist.
Probably so? Whoa. No. Definitely not.

Whatever mathematician may have imagined it wasn't the set of all sets that don't include themselves. They imagined something, but not the set itself.

Originally Posted by Torin
Can you imagine a consistent geometry that doesn't obey Euclid's axioms? Nobody could until non-Euclidean geometry was discovered.
So what? How does that falsify my claim? You're being illogical here.

For your information, at 14 I invented form scratch a new type of perspective similar to that of the fish-eye, before I saw my first fish-eye photo. I imagined it, and not only was it logically possible but it turned out to be actual.

And so you failed to mention that when non-Euclidean geometry was first proposed, people still though it couldn't exist. It's only with General Relativity that it became clear that not only was it a logical possibility but there was a probability that it was actual.

Originally Posted by Torin
This is also very subjective. You say you cannot imagine God, but plenty of people think they can. Whose imagination is the standard for logical possibility?
People don't imagine God. They imagine something they call God. So, again, whatever people imagine, assuming their brain works well, it is logically possible. Still, where would be the problem with imagining that God exists? How would that be a counterexample to my thesis?
EB

5. All is imagination.
Reality is your imagination of what is, to you, the current state of reality. The map is not the territory.
A plan is imagination of what is, to you, a possible future.
A daydream is imagination of what is, to you, a possible or impossible future. If I were president.
A dream is imagination unconstrained by reality. I can fly like Superman.

6. Originally Posted by Speakpigeon
If I can imagine it, it's logically possible.
Reminds me of those officers convinced that if an order was grammatically correct, it could be obeyed. Not concerned with law, tech, physics....

7. I can imagine myself flapping my arms and flying.
I can imagine having sex with 100 young women who exist only to please me.
Ican imagine war between NATO and Russia.
I can imagine the future use of nuclear weapons.

8. Originally Posted by George S
All is imagination.
Reality is your imagination of what is, to you, the current state of reality. The map is not the territory.
A plan is imagination of what is, to you, a possible future.
A daydream is imagination of what is, to you, a possible or impossible future. If I were president.
A dream is imagination unconstrained by reality. I can fly like Superman.
Certainly not as I meant the word "imagine" here, which happens to be what is usually meant, according to dictionaries I don't need to imagine...
Imagine
1. To form a mental picture or image of: imagined a better life abroad.
Perception is not imagination.

Sensations, memories, reflection, conception, intuition etc. are not imagination.

You're merely redefining the word "imagination". So, derail.

EB

9. Originally Posted by Keith&Co.
Originally Posted by Speakpigeon
If I can imagine it, it's logically possible.
Reminds me of those officers convinced that if an order was grammatically correct, it could be obeyed. Not concerned with law, tech, physics....
Try again whenever you can articulate a point relevant to the topic.

Although the best explanation is that you understand diddly squat about logical possibility.
EB

- - - Updated - - -

Originally Posted by steve_bank
I can imagine myself flapping my arms and flying.
I can imagine having sex with 100 young women who exist only to please me.
Ican imagine war between NATO and Russia.
I can imagine the future use of nuclear weapons.
No you can't.

Saying you do won't do.
EB

10. Originally Posted by Speakpigeon
Originally Posted by George S
All is imagination.
Reality is your imagination of what is, to you, the current state of reality. The map is not the territory.
A plan is imagination of what is, to you, a possible future.
A daydream is imagination of what is, to you, a possible or impossible future. If I were president.
A dream is imagination unconstrained by reality. I can fly like Superman.
Certainly not as I meant the word "imagine" here, which happens to be what is usually meant, according to dictionaries I don't need to imagine...
Imagine
1. To form a mental picture or image of: imagined a better life abroad.
Perception is not imagination.

Sensations, memories, reflection, conception, intuition etc. are not imagination.

You're merely redefining the word "imagination". So, derail.

EB
What you do with those perceptions is generate a story about reality in your head. A "map" of reality. "Forming a mental image of..." Have you ever gotten a fact wrong? Had a memory (map) that turned out to not be the case? To this degree you are imagining.

As for being a derail, let's just take the last one: I can imagine flying like Superman, so "If I can imagine it, it's logically possible" is false. Right on topic.

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