Re: Some perspective on perspective
« Reply #40 on: May 01, 2016, 04:20:35 PM »
You earlier said "The model the Greeks proposed is clearly wrong when it comes to things that are far away. The simple fact is that the lines touch" and here YOU are simply mistaken! As I have tried to get across with parallel lines the simple fact is that the lines DO NOT touch, they do APPEAR to TOUCH.

If one looks at the scene, they do touch. It's a factual statement. "Appear" is implied.

According to the mathematical model of the Ancient Greeks, they should never touch.

Math is a purely logical construction; it concerns what can be deduced from an initial set of propositions. So the only way to refute a mathematical conclusion (i.e., a statement that proposition P can be deduced logically from the initial premises A, B, C,…) is to show a logical error in the proof.

In the Elements, Euclid defined parallel lines as lines in the same plane that never meet no matter how far they are extended in either direction. So if two lines meet, by definition they are not parallel in Euclid’s sense. Saying “these two parallel lines actually touch, therefore Euclid was wrong,” is like saying “this triangle has four sides, therefore Euclid was wrong about triangles.”

If logically valid math gives you the wrong answer when applied to the real world, the problem is with how you have applied it, not with the math.

Example: Ancient Greek arithmetic says 1 + 1 = 2. So you take one rabbit and put it in an enclosure. Then you put another rabbit of the opposite sex in the enclosure. You come back in a few months, find a dozen rabbits in the enclosure, and declare that the world model of Greek arithmetic is wrong. But the error is actually in how you have applied the math.

Example: Euclid proved that, given the axioms, postulates, and definitions from which he begins, the angles of a triangle on a flat plane sum to two right angles (180 degrees). No one has found an error in his proof in 2,300 years. Now you find a triangle somewhere, measure the three angles, and find that the sum is 181 degrees. Aha, you say, Euclid’s world view is wrong. No, his proof is correct. There could be several reasons why your sum differs from Euclid’s: Your measuring instruments could be inaccurate. Rounding errors could add up to a degree. You lost your glasses and misread your instruments. The sides of the triangle are not perfectly straight. Or, the sides of the triangle are actually great-circle paths on the surface of a spherical planet, whereas Euclid’s proof concerns triangles on a flat plane.

Example: You look at straight railroad tracks extending miles into the distance on a flat plain. You observe that what your brain tells you are rail lines in your field of vision meet at the horizon, and conclude that Euclid’s world view is wrong. No, you’ve just misapplied his reasoning. He never said that parallel lines will never appear to meet in your field of vision, no matter how far away they are. Now you look at the lines through a telescope, and the lines you see don’t meet any more. Hmm.

So what you seem be saying is that if lines in your field of vision actually meet as interpreted by your brain, then the lines out there, miles away, actually do meet. But that doesn’t explain why they don’t meet any more when viewed through a telescope. Nor is it consistent with our everyday observation that what looks like an ellipse turns out to be a circle when viewed from a different angle.

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Offline Woody

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Re: Some perspective on perspective
« Reply #41 on: May 01, 2016, 07:10:08 PM »
So Tom thinks the math is wrong since if we look at something like railroad tracks and have enough viewing distance they appear to touch.

The math tells us they do not actually touch and a very simple observation will confirm this.  Just watch a train travel down those tracks.  Unless the train shrinks as it gets further away.

Tom why not show us using this faulty math where it says two parallel lines actually touch and not appear to touch do to perspective?

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Offline Tom Bishop

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Re: Some perspective on perspective
« Reply #42 on: May 01, 2016, 07:14:32 PM »
So Tom thinks the math is wrong since if we look at something like railroad tracks and have enough viewing distance they appear to touch.

The math tells us they do not actually touch and a very simple observation will confirm this.  Just watch a train travel down those tracks.  Unless the train shrinks as it gets further away.

Tom why not show us using this faulty math where it says two parallel lines actually touch and not appear to touch do to perspective?

If one looks at the scene, they do touch. It's a factual statement. "Appear" is implied.

According to the mathematical model of the Ancient Greeks, they should never touch.
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

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Offline Tom Bishop

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Re: Some perspective on perspective
« Reply #43 on: May 01, 2016, 07:22:42 PM »
Math is a purely logical construction; it concerns what can be deduced from an initial set of propositions. So the only way to refute a mathematical conclusion (i.e., a statement that proposition P can be deduced logically from the initial premises A, B, C,…) is to show a logical error in the proof.

An error in the proof is that parallel lines seem to converge in contradiction of theory.

Quote
In the Elements, Euclid defined parallel lines as lines in the same plane that never meet no matter how far they are extended in either direction. So if two lines meet, by definition they are not parallel in Euclid’s sense. Saying “these two parallel lines actually touch, therefore Euclid was wrong,” is like saying “this triangle has four sides, therefore Euclid was wrong about triangles.”

Elucid was wrong about a lot of things. Look up Zeno's Paradox. The Greek model of the universe is flimsy.

Quote
Example: You look at straight railroad tracks extending miles into the distance on a flat plain. You observe that what your brain tells you are rail lines in your field of vision meet at the horizon, and conclude that Euclid’s world view is wrong. No, you’ve just misapplied his reasoning. He never said that parallel lines will never appear to meet in your field of vision, no matter how far away they are. Now you look at the lines through a telescope, and the lines you see don’t meet any more. Hmm.

So what you seem be saying is that if lines in your field of vision actually meet as interpreted by your brain, then the lines out there, miles away, actually do meet. But that doesn’t explain why they don’t meet any more when viewed through a telescope. Nor is it consistent with our everyday observation that what looks like an ellipse turns out to be a circle when viewed from a different angle.

If the Greek models are corrupted by illusions at long distances then we must admit that there are illusions present in the subject matter and that the unsatisfactory Greek models cannot be used as a disproof of what a Flat Earth sun might or might not do.
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

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Offline Woody

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Re: Some perspective on perspective
« Reply #44 on: May 01, 2016, 07:57:12 PM »
So Tom thinks the math is wrong since if we look at something like railroad tracks and have enough viewing distance they appear to touch.

The math tells us they do not actually touch and a very simple observation will confirm this.  Just watch a train travel down those tracks.  Unless the train shrinks as it gets further away.

Tom why not show us using this faulty math where it says two parallel lines actually touch and not appear to touch do to perspective?

If one looks at the scene, they do touch. It's a factual statement. "Appear" is implied.

According to the mathematical model of the Ancient Greeks, they should never touch.

The Greek model does not say they actually touch.  That is why I asked you to show us where it says they actually touch.  The important part is appearing to touch and actually touching.

I have not found anything saying two parallel actually touch, only appear to touch as the result of perspective.  I can find things saying parallel will never touch and can use what the Greeks came up with those lines do not touch at any distance.

They do not touch:


They can appear to touch:




Using the Greek model you claim is wrong it says two parallel lines never touch.


The only argument I can think of you can make is something similar to this:



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Offline Tom Bishop

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Re: Some perspective on perspective
« Reply #45 on: May 01, 2016, 10:04:02 PM »
The Greek model does not say they actually touch.  That is why I asked you to show us where it says they actually touch.  The important part is appearing to touch and actually touching.

If one looks at the scene, they do touch. It's a factual statement. "Appear" is implied.

According to the mathematical model of the Ancient Greeks, they should never touch.
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

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Offline Captain Magpie

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Re: Some perspective on perspective
« Reply #46 on: May 01, 2016, 11:26:38 PM »
The Greek model does not say they actually touch.  That is why I asked you to show us where it says they actually touch.  The important part is appearing to touch and actually touching.

If one looks at the scene, they do touch. It's a factual statement. "Appear" is implied.

According to the mathematical model of the Ancient Greeks, they should never touch.
Are you down with your Orwellian double-speak yet?

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Offline rabinoz

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Re: Some perspective on perspective
« Reply #47 on: May 01, 2016, 11:30:36 PM »
Tom at what distance does math no longer work?  1, 10, 100, 1000, 10000 or further?

Just your estimate where math fails to be able to give good estimates or right answers?

I can use that math to estimate ranges when I sail and had accurate results.

I used it recently to determine how much fuel a rounded tank on my boat could hold and the answer I got was verified to be correct when I put fuel in it.

I used it for celestial navigation and determined my position accurately with noon and star sightings.

Throughout my life I have used it in my career and personal life and consistently had it verified since it gave me the right answers that were verified correct when applied to projects, the amount of material needed, how much liquid something could hold, etc.

So when does math no longer work?  I ask because you seem assured you are right and must know at what distances it is no longer accurate.  My experience is that it does return the right answers. An experience I highly doubt that the majority of people would say the opposite.

Did you have evidence of being correct or is the only evidence you offer is if the Greeks were right you are wrong about the shape of the Earth?

It certainly does not work at the vanishing point of railroad tracks, as the math says that they do not touch, when they observably do touch. The observation is evidence that the world model as they described it is wrong.
It certainly does work with the railway tracks. They do not touch, they only appear to touch. How many times do we have to say the same thing?
PROOF:
Imagine the lines in question are railway tracks. They would appear to touch in about 3 miles (at a guess), but quite importantly they clearly do not touch, or that TGV flying past us at 200 mph is going to be in BIG BIG BIG TROUBLE in a bit under one minute! 

Go and have a look here if want to see what might happen Tgv crash, not the same cause.

Yes, I know I posted it before, but sometimes reality takes while to sink in.
Clearly railway tracks DO NOT ACTUALLY MEET, THEY ONLY APPEAR to MEET!
As I posted earlier in many cases we can test whether lines meet, by simply travelling to where they appear to meet.

Of course in some cases we may not be certain that the "lines" are truly parallel. That is no reflection on the geometry.

I'm afraid you must live in a different world to the rest of us, one quite divorced from reality!

If one looks at the scene, they do touch. It's a factual statement. "Appear" is implied.

According to the mathematical model of the Ancient Greeks, they should never touch.
According to the mathematical model of the Ancient Greeks, they should never touch.
And they never do touch - as I believe I quite convincingly proved with the railway tracks!

YOU claim: "If one looks at the scene, they do touch. It's a factual statement. "Appear" is implied."
And YOU say the "Appear" is implied. But the Greeks did not ever say "they do touch".

In fact what Euclid did say in his Fifth Postulate was:

If the sum of the interior angles α and β is less than 180°,
the two straight lines, produced indefinitely, meet on that side.
What Euclid states is that lines which are not parallel do converge. He does not even say that parallel do not converge.

Now I am no expert on Greek geometry (and of course we do not simply "rely on Greek geometry" anyway!), so maybe you can show where they even say that parallel lines "appear to touch" somewhere!

Can't you ever see the difference between what appears to be true and what is actually true?

If the railway tracks actually did meet we would have a horrendous smash. We do not have a smash (hopefully!) so the railway tracks do not meet at their "vanishing point".

Still I guess there is not point discussing this further. For some people waords have well defined meanings, for others:
Quote from: Lewis Carroll
"When I use a word," Humpty Dumpty said in rather a scornful tone, "it means just what I choose it to mean — neither more nor less."
PS Never, ever change your mind and accept the fact that the earth is really a Globe. We just could not take your logic on our side!

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Offline Tom Bishop

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Re: Some perspective on perspective
« Reply #48 on: May 01, 2016, 11:54:13 PM »
Tom at what distance does math no longer work?  1, 10, 100, 1000, 10000 or further?

Just your estimate where math fails to be able to give good estimates or right answers?

I can use that math to estimate ranges when I sail and had accurate results.

I used it recently to determine how much fuel a rounded tank on my boat could hold and the answer I got was verified to be correct when I put fuel in it.

I used it for celestial navigation and determined my position accurately with noon and star sightings.

Throughout my life I have used it in my career and personal life and consistently had it verified since it gave me the right answers that were verified correct when applied to projects, the amount of material needed, how much liquid something could hold, etc.

So when does math no longer work?  I ask because you seem assured you are right and must know at what distances it is no longer accurate.  My experience is that it does return the right answers. An experience I highly doubt that the majority of people would say the opposite.

Did you have evidence of being correct or is the only evidence you offer is if the Greeks were right you are wrong about the shape of the Earth?

It certainly does not work at the vanishing point of railroad tracks, as the math says that they do not touch, when they observably do touch. The observation is evidence that the world model as they described it is wrong.
It certainly does work with the railway tracks. They do not touch, they only appear to touch. How many times do we have to say the same thing?
PROOF:
Imagine the lines in question are railway tracks. They would appear to touch in about 3 miles (at a guess), but quite importantly they clearly do not touch, or that TGV flying past us at 200 mph is going to be in BIG BIG BIG TROUBLE in a bit under one minute! 

Go and have a look here if want to see what might happen Tgv crash, not the same cause.

Yes, I know I posted it before, but sometimes reality takes while to sink in.
Clearly railway tracks DO NOT ACTUALLY MEET, THEY ONLY APPEAR to MEET!
As I posted earlier in many cases we can test whether lines meet, by simply travelling to where they appear to meet.

Of course in some cases we may not be certain that the "lines" are truly parallel. That is no reflection on the geometry.

I'm afraid you must live in a different world to the rest of us, one quite divorced from reality!

If one looks at the scene, they do touch. It's a factual statement. "Appear" is implied.

According to the mathematical model of the Ancient Greeks, they should never touch.
According to the mathematical model of the Ancient Greeks, they should never touch.
And they never do touch - as I believe I quite convincingly proved with the railway tracks!

YOU claim: "If one looks at the scene, they do touch. It's a factual statement. "Appear" is implied."
And YOU say the "Appear" is implied. But the Greeks did not ever say "they do touch".

In fact what Euclid did say in his Fifth Postulate was:

If the sum of the interior angles α and β is less than 180°,
the two straight lines, produced indefinitely, meet on that side.
What Euclid states is that lines which are not parallel do converge. He does not even say that parallel do not converge.

Now I am no expert on Greek geometry (and of course we do not simply "rely on Greek geometry" anyway!), so maybe you can show where they even say that parallel lines "appear to touch" somewhere!

Can't you ever see the difference between what appears to be true and what is actually true?

If the railway tracks actually did meet we would have a horrendous smash. We do not have a smash (hopefully!) so the railway tracks do not meet at their "vanishing point".

Still I guess there is not point discussing this further. For some people waords have well defined meanings, for others:
Quote from: Lewis Carroll
"When I use a word," Humpty Dumpty said in rather a scornful tone, "it means just what I choose it to mean — neither more nor less."
PS Never, ever change your mind and accept the fact that the earth is really a Globe. We just could not take your logic on our side!

Well, I don't believe the sun is actually touching the earth. Obviously I'm saying that they apparently touch when I say that they touch in the parallel line example. Can't you just move on, or do I need to repeat myself another 10 times?
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

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Offline rabinoz

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Re: Some perspective on perspective
« Reply #49 on: May 02, 2016, 01:59:13 AM »
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Well, I don't believe the sun is actually touching the earth. Obviously I'm saying that they apparently touch when I say that they touch in the parallel line example. Can't you just move on, or do I need to repeat myself another 10 times?

Well, neither do I. But, if that is what you were trying to say whyever did you make such silly claims about the ancient Greeks.

What I do claim is that the sun appears to go down behind the horizon (that is much further from us than the horizon).

Sun Setting at Barhhill, WA
   

Sun has set, Barnhill, WA
Now according to your model at sunset:
the sun which is actually some 3,000 miles (your figures not mine!) above the earth and
at distance of roughly from the observer (on the equator at the equinox) 8,800 miles hence
at an elevation of roughly 20° can ever appear behind or even below the visible horizon.

When you marry that with Rowbotham's explanation of the sun staying the same size throughout the day.
Quote from: Earth not a Globe p.128, by Parallax
CAUSE OF SUN APPEARING LARGER WHEN RISING AND SETTING THAN AT NOONDAY.
IT is well known that when a light of any kind shines through a dense medium it appears larger, or rather gives a greater "glare," at a given distance than when it is seen through a lighter medium. This is more remarkable when the medium holds aqueous particles or vapour in solution, as in a damp or foggy atmosphere. Anyone may be satisfied of this by standing within a few yards of an ordinary street lamp, and noticing the size of the flame; on going away to many times the distance, the light or "glare" upon the atmosphere will appear considerably larger.

This is utter rubbish because the sun staying the same says is the rule (rather than the exception) and happens in dry or wet conditions.

Offline CableDawg

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Re: Some perspective on perspective
« Reply #50 on: May 03, 2016, 03:03:41 AM »
The Greek model does not say they actually touch.  That is why I asked you to show us where it says they actually touch.  The important part is appearing to touch and actually touching.

If one looks at the scene, they do touch. It's a factual statement. "Appear" is implied.

According to the mathematical model of the Ancient Greeks, they should never touch.

Repetition of something may give a sense of security and fact to you as an individual but, ultimately, the repetition of a lie does not make it true.

Somehow you are, in your argument, defining appear as fact.  By the definition you're trying to cram appear into above, every time I stand in front of a mirror I've made a second version of myself since it appears that I'm standing there looking at myself.

Re: Some perspective on perspective
« Reply #51 on: May 05, 2016, 10:01:02 AM »
Yes, there are multiple reasons why they can appear to touch. Insufficient resolving power of the eye/camera (as has been stated multiple times) is one of them. Decreased clarity due to atmospheric scattering is another. But this is all irrelevant. The basic geometry deals with a perfect world. There is no such thing as perfectly parallel lines, or a perfectly clear atmosphere. But that doesn't mean the entire theory is useless.

If their theory doesn't match observations it means the theory is wrong and must be modified or discarded.

Not necessarily. It might mean your basic assumptions are wrong. For example, the "ancient greek math" assumes that you have perfect resolving power and no atmospheric effects. Clearly these are bad assumptions. So what should we do? Should we just give up on basic geometry and declare that math is useless? Of course not, that would be silly.

Instead, let's come up with some more theories that describe how these "bad assumptions" affect the result from the original theory.

Theory A: Anything smaller than about one arcminute in diameter (.017 degrees) is not distinguishable by the human eye.
Theory B: Stuff becomes blurry when viewed from really far away through an atmosphere

So now lets combine the "ancient greek math" (which describes a perfect world) with Theory A (which takes into account one of those imperfections).

Train Track Example:
You are looking down some train tracks that extend a long way into the distance. They are separated by a distance of 4 feet. Let's calculate how far apart those train tracks should appear 3 miles (15840 feet) away using the "ancient greek math".

angle = tan-1(4/15840) = 0.014 degrees

So, according to the "ancient greek math", the tracks should appear to be separated by 0.014 degrees. However, according to "Theory A", the human eye can't distinguish anything less than 0.017 degrees. Therefore, we should expect the tracks to appear to touch according to the human eye, even though the "ancient greek math" says they technically aren't touching.

The "ancient greek math" doesn't tell the entire story. It doesn't bother to take into account the limitations of the human eye, or cameras, or the atmosphere. But that doesn't mean it is useless. It is a starting point.

If you want to show that the "ancient greek math" is wrong, then you need to show an error in their proof. You have not even attempted that.

However, if you want to show that the "ancient greek math" is not applicable to the real world, then you need to show us a contradiction between the mathematical result and reality that can't be explained by some known phenomenon. So far, you have only repeatedly stated "the math says they should never touch, but they do touch". This contradiction can easily be explained by the limitations of the human eye or camera (as shown in my example above).

Sun Example:
On the other hand, the "ancient greek math" states that the sun should be separated from the horizon by about 20 degrees at a minimum. Assuming the sun is 3000 miles high, and an equatorial diameter of 8000 miles.

angle = tan-1(3000/8000) = 20 degrees

Is there any phenomenon that you know of that can make 20 degrees appear to be 0 degrees? I don't. Most cameras can easily distinguish stuff less than 20 degrees assuming they have more than 3 pixels. We can't blame atmospheric scattering, because the we can still distinguish the actual sun, which is much less than 20 degrees.

Unless you can come up with an explanation for this difference, blaming the "ancient greek math" just seems like a refusal to accept that your model might be wrong.


Sorry for the late reply. Busy busy.
« Last Edit: May 05, 2016, 10:12:48 AM by TotesNotReptilian »

Re: Some perspective on perspective
« Reply #52 on: May 05, 2016, 10:18:49 AM »
TL;DR of previous long-winded post:

So far, you have only repeatedly stated "the math says they should never touch, but they do touch". This apparent contradiction can easily be explained by the limitations of the human eye or camera.

Re: Some perspective on perspective
« Reply #53 on: May 05, 2016, 09:08:27 PM »
Math is a purely logical construction; it concerns what can be deduced from an initial set of propositions. So the only way to refute a mathematical conclusion (i.e., a statement that proposition P can be deduced logically from the initial premises A, B, C,…) is to show a logical error in the proof.

An error in the proof is that parallel lines seem to converge in contradiction of theory.

I’m having a hard time making sense of your responses, Tom. You seem to be saying that if parallel lines, such as railroad tracks on a flat surface, seem to your eyes (your brain, actually) to meet in the distance, then that refutes Euclid somehow. But so far as I know he never claimed that parallel lines will never appear to meet no matter how distant they are, and even if he had made such a claim, it wouldn’t have been as a part of any geometrical theorem.

As others have pointed out, our eyes have limited resolution capabilities: our vision can’t separate two objects 0.001 seconds of arc apart in our field of view. But they are still two separate objects.

 Look, Tom, if you’re trying to make converts to FET, this isn’t the way to do it. You need to write in such a way that RE believers as well as fence-sitters can at least make sense of what you’re saying.

Quote
Quote
In the Elements, Euclid defined parallel lines as lines in the same plane that never meet no matter how far they are extended in either direction. So if two lines meet, by definition they are not parallel in Euclid’s sense. Saying “these two parallel lines actually touch, therefore Euclid was wrong,” is like saying “this triangle has four sides, therefore Euclid was wrong about triangles.”

Elucid was wrong about a lot of things. Look up Zeno's Paradox. The Greek model of the universe is flimsy.

Zeno’s Paradoxes are interesting philosophical questions, but I don’t see what they have to do with perspective, the topic of my OP.

And I haven’t seen a reply from any FE believer to my demonstration upthread that the sun would have to be at least a million miles away for it to appear to touch the horizon while remaining 3000 miles above the earth.

Re: Some perspective on perspective
« Reply #54 on: May 06, 2016, 02:45:59 AM »
The lines don't touch. The sky doesn't meet the ocean. But it appears to. We know it doesn't, it would be like chasing a rainbow trying to find the spot where the sky touches the ocean. It's an optical "illusion," but that doesn't mean it can't be described mathematically. What do you think every 3d engine ever has done to show rigid geometric 3d world in a way that mimics reality?

Euclid geometry obviously isnt used to describe the world as it appears, rather as it is. Even then it can be debated whether or not any of these perfect straight lines and circles even exist in reality.

Math, anyway you chalk it up, is a purely imaginary construct. It doesn't "exist," it just aids us in our description of phenomena and our natural desire for logical order in our universe. Even Einstein said "As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality."

That being said it can never be used to completely describe the whole of our existence.

Re: Some perspective on perspective
« Reply #55 on: May 06, 2016, 06:41:28 PM »
The lines don't touch. The sky doesn't meet the ocean. But it appears to.

Yes, but WHY does it appear to touch? Hint: because the angle between them is really really small.

The angle between the sun and the horizon on a flat earth is NOT really really small. 20 degrees is not small at all. There is absolutely no reason why 20 degrees should appear as 0 degrees to us. Does this obvious inconsistency really not bother any flat-earthers?

Here is a to-scale diagram. If you really don't trust trigonometry, you can use a protractor.



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Offline Tom Bishop

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Re: Some perspective on perspective
« Reply #56 on: May 06, 2016, 06:44:58 PM »
The lines don't touch. The sky doesn't meet the ocean. But it appears to.

Yes, but WHY does it appear to touch? Hint: because the angle between them is really really small.

The angle between the sun and the horizon on a flat earth is NOT really really small. 20 degrees is not small at all. There is absolutely no reason why 20 degrees should appear as 0 degrees to us. Does this obvious inconsistency really not bother any flat-earthers?

Here is a to-scale diagram. If you really don't trust trigonometry, you can use a protractor.



Show us a real world example of how objects at that sort of distance appear and behave.
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

Re: Some perspective on perspective
« Reply #57 on: May 06, 2016, 06:50:48 PM »
The lines don't touch. The sky doesn't meet the ocean. But it appears to.

Yes, but WHY does it appear to touch? Hint: because the angle between them is really really small.

The angle between the sun and the horizon on a flat earth is NOT really really small. 20 degrees is not small at all. There is absolutely no reason why 20 degrees should appear as 0 degrees to us. Does this obvious inconsistency really not bother any flat-earthers?

Here is a to-scale diagram. If you really don't trust trigonometry, you can use a protractor.



Show us a real world example of how objects at that sort of distance appear and behave.

Show us any reason at all why an object would behave differently at that distance than at any other distance.

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Offline Tom Bishop

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Re: Some perspective on perspective
« Reply #58 on: May 06, 2016, 06:57:39 PM »
Show us any reason at all why an object would behave differently at that distance than at any other distance.

A laser appears to be straight and constant locally, but at far distances, the beam widens out.

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



Ice bergs may seem to float on the water locally, but from far away they may seem to float in the air.

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



So yes, we will need some kind of real evidence that things work as you say they work, not a diagram.
« Last Edit: May 06, 2016, 07:02:00 PM by Tom Bishop »
"The biggest problem in astronomy is that when we look at something in the sky, we don’t know how far away it is" — Pauline Barmby, Ph.D., Professor of Astronomy

Re: Some perspective on perspective
« Reply #59 on: May 06, 2016, 07:23:20 PM »
Show us any reason at all why an object would behave differently at that distance than at any other distance.

A laser appears to be straight and constant locally, but at far distances, the beam widens out.

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



Ice bergs may seem to float on the water locally, but from far away they may seem to float in the air.

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



So yes, we will need some kind of real evidence that things work as you say they work, not a diagram.

Both of those phenomena are well understood, and would not cause the sun to appear below the horizon when it is actually 20 degrees above the horizon.

The iceberg mirage is caused by refraction. It is heavily dependent on air and surface temperature. It varies wildly. Sunsets happen every single day, everywhere, regardless of the weather. So no, this is not a possibility.

The laser beam divergence... I have no idea how it is relevant. Perhaps you can explain to us how it would cause the sun to appear below the horizon?