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Offline AATW

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Re: Empirical Validation of Perspective
« Reply #20 on: July 02, 2018, 02:29:11 PM »
I gave you an example. You agreed with the example.
I agreed that:

Quote
It's widely observable that overhead receding bodies move at a more constant pace into the horizon the higher they are.

Yes. True. My diagram shows why that's true. But the claim in the Wiki that the speed of the sun is constant because:

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The sun moves constant speed into the horizon at sunset because it is at such a height that already beyond the apex of perspective lines. It has maximized the possible broadness of the lines of perspective in relation to the earth. It is intersecting the earth at a very broad angle.

Is nonsensical. It's actually just a complete gibberish sentence. I wouldn't even know how to go about trying to test that. What does it even mean? What you're doing is taking an observation and then making up some gibberish explanation which is impossible to test. It's like me saying that rainbows are created by invisible rainbow pixies which come out when it rains, but only if it's sunny too. And they line themselves up in a circle and shine their little rainbow lanterns. Prove me wrong! Well, how? How am I going to test that?

The way things are discovered in the real world are:
1) Make an observation
2) Create a hypothesis which explains that observation.
3) Devise some experiments to test that hypothesis. If the tests fail then back to step 2.

You lot never get beyond the second step. And your hypothesis are just things like "the sun stays the same size even though it's really getting further away because there's a magnification effect which by an amazing coincidence exactly counteracts the diminishing size".
Your "evidence" is then that the sun remains the same size! Well we know that, that's where you started! It's completely circular reasoning.
Tom: "Claiming incredulity is a pretty bad argument. Calling it "insane" or "ridiculous" is not a good argument at all."

TFES Wiki Occam's Razor page, by Tom: "What's the simplest explanation; that NASA has successfully designed and invented never before seen rocket technologies from scratch which can accelerate 100 tons of matter to an escape velocity of 7 miles per second"

Re: Empirical Validation of Perspective
« Reply #21 on: July 02, 2018, 04:41:01 PM »
I'm glad to see that the video sparked a conversation at least. I was rather hoping that people would try the experiment. I figure if you participate, you're less antagonistic towards the results. So that part didn't work out... now let's discuss the results...

But you already know what I'm going to say. Where did the Ancient Greeks ever provide evidence for their perspective model?

Lets just agree not to have that conversation again for the 100'th time and agree that the Ancient Greek's Continuous Universe model is full of assumptions which have not been demonstrated.

Did you notice that in the video, I made no mention of the Ancient Greeks or a perspective model at all? This video was all about doing it empirically. That's the zetetic way right? Since the logical reasoning behind WHY this happens is controversial, let's shelve that for now. Let's just discuss what we saw first.

What we see very clearly is that apparent sizes (and apparent distances of any kind) shrink with distance from the viewer. We further showed that apparent sizes are inversely proportional to the distance from the viewer. We didn't use any theory to arrive at this. This comes from photographs and measurements.

It's widely observable that overhead receding bodies move at a more constant pace into the horizon the higher they are. For an example imagine that someone is flying a jet into the distance at an illegal altitude of 300 feet. He seems to zoom by pretty fast when he is flies over your head, only slowing down when he is off in the far distance.

Now consider what happens when a jet flies over your head at 45,000 feet. At that altitude a jet appears to move slowly across the sky, throughout its extent, despite that it is traveling at the same speed as the previous plane. With greater altitude the plane seems to move more consistently across the sky. It does not zoom by overhead, only seeming to slow when in the far distance.

Does our photographic observation match the example of planes flying overhead? Yes. Perfectly. As high as any plane can fly, this observation matches it.
When it is directly overhead at 300 ft, it is 300 ft from you. We'll call the apparent speed at that point s.
When the plane moves forward 300 ft, its distance from you is now 424 ft, and that will make its new apparent speed 0.707s.
Let the plane get forward 1000 ft, and its distance from you will be 1044 ft giving it an apparent speed of 0.287s.
"He seems to zoom by pretty fast when he is flies over your head, only slowing down when he is off in the far distance." Check.
Now consider the plane at 45,000 ft. Directly overhead, its apparent speed will be 0.00667s.
Let that plane move forward 300 ft, so it is now 45,001 ft from you. Its apparent speed will be 0.00667s. (It's lower, but you must go past 3 significant figures to see it.)
Let the plane get to 1000 ft in front of you. Its distance is 45,011 ft from you. Apparent speed 0.00667s. (Still lower, but not quite showing to 3 significant figures yet.)
"With greater altitude the plane seems to move more consistently across the sky. It does not zoom by overhead, only seeming to slow when in the far distance." Check.

Quick review... how did I get all those apparent speeds? They come from speed = distance/time. "apparent speed" = "apparent distance" / time. Simply take the inverse relationship between "apparent distance" and distance from viewer, and apply that. Recall that we got the inverse relationship not from any theory, but from empirical evidence.

Did my lego's really show that? Actually they really did. From the legos, I discovered the inverse relationship between apparent distance and distance from the viewer. I tested this with different ranges of size and distance, but certainly not out to anything close to 45,000 ft. But when I applied what I saw at 1 ft, 10 ft, and 100 ft to your example of 45,000 ft; the results worked! If you take a video of a plane travelling overhead, you could validate this.

But I only measured the heights of objects getting farther away from the viewer horizontally. Could it be different for different directions? Why not investigate? You can measure the widths of objects instead of heights, and you'll get the same result. Measure the apparent distance between the objects, and the result is the same. Do the experiment pointing the camera up vertically instead, and see if the results are any different.

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Offline Tom Bishop

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Re: Empirical Validation of Perspective
« Reply #22 on: July 02, 2018, 05:34:05 PM »
Some quotes related to Euclid's parallel line postulate courtesy of the Department of Mathematics at UC Riverside:

http://math.ucr.edu/~res/math133/geometrynotes05a.f13.pdf

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We have already mentioned in Section II.5 that the final assumption in Euclid’s  Elements  (the so – called Fifth Postulate) is far more complicated than the others. Furthermore, the proofs of the first  28 results in the Elements do not use the Fifth Postulate. In addition, there are general questions whether this postulate corresponds to physical reality because it involves objects which are too distant to be observed or questions about measurements that cannot necessarily be answered conclusively because there are always limits to the precision of physical measurements.

A nice quote from Immanuel Kant:

Quote from: Immanuel Kant
"The concept of [Euclidean] space is by no means of empirical origin, but is an inevitable necessity of thought."

Kant, Critique of Pure Reason (1781)

Another description illustrating the parallel line postulate.

As we can see, it is candidly admitted that this idea is not empirical. It is a hypothetical house of cards.
« Last Edit: July 02, 2018, 05:59:27 PM by Tom Bishop »

Re: Empirical Validation of Perspective
« Reply #23 on: July 02, 2018, 05:51:19 PM »
Some quotes related to Euclid's parallel line postulate courtesy of the Department of Mathematics at UC Riverside:

http://math.ucr.edu/~res/math133/geometrynotes05a.f13.pdf

Quote
We have already mentioned in Section II.5 that the final assumption in Euclid’s  Elements  (the so – called Fifth Postulate) is far more complicated than the others. Furthermore, the proofs of the first  28 results in the Elements do not use the Fifth Postulate. In addition, there are general questions whether this postulate corresponds to physical reality because it involves objects which are too distant to be observed or questions about measurements that cannot necessarily be answered conclusively because there are always limits to the precision of physical measurements.

A nice quote from Immanuel Kant:

Quote from: Immanuel Kant
"The concept of [Euclidean] space is by no means of empirical origin, but is an inevitable necessity of thought."

Kant, Critique of Pure Reason (1781)

A good description illustrating the parallel line postulate.


As we can see, it is candidly admitted that this idea is not empirical. It is a hypothetical house of cards.
Tom, I understand that you have strong objections to the theory behind perspective. So instead of fixating on that, let's instead look at the empirical evidence. That was the entire point of the video. Let's focus on the evidence, please.

Offline edby

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Re: Empirical Validation of Perspective
« Reply #24 on: July 02, 2018, 05:53:25 PM »
A separate discussion on the parallel postulate would be interesting, now Tom has raised it.

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Offline Bobby Shafto

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Re: Empirical Validation of Perspective
« Reply #25 on: July 02, 2018, 06:58:25 PM »
Tom, I understand that you have strong objections to the theory behind perspective. So instead of fixating on that, let's instead look at the empirical evidence. That was the entire point of the video. Let's focus on the evidence, please.

Tom,

You originally signed up to participate and you filled out the pre-experiment questionnaire. But you didn't follow-up and contribute with an observational input of your own.

Maybe I'm slow on the uptake, but for an empiricist, you sure do do a lot of "imagine this..." and "pretend that..." You like analogical models and thought experiments. I do too, as long as they correctly model what it is they are supposed to be modeling. (Optical artifacts of a camera or camera lense, for instance, do not model light interacting with an atmosphere.)   

A model goes a long way toward creating an experiment and predicting an outcome, so that when you actually do perform an experiment and collect data, you can see if your model supported whatever theory or expectation you might have had. But it has to go beyond the paper and beyond the thought experiment, particularly if you champion empiricism. Maybe you don't have to do it personally. You may be physically unable or lack access to resources necessary, but if someone else does, you/we should be able to examine and analyze that data, that experimental setup. It can't be just an anecdotal "I did x and saw y".

Your abandonment of this experiment and your after-the-fact critique are disappointing.


This topic has brought this wiki page to my attention. I don't believe I had seen it before. What is the foundation for this claim, which has survived unedited since the page's creation:
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The sun moves constant speed into the horizon at sunset because it is at such a height that already beyond the apex of perspective lines. It has maximized the possible broadness of the lines of perspective in relation to the earth.
Does this suggest that there is a distance/range threshold at which point observations based on angular dimensions are different from observations closer than that threshold? If so, what distance is that and how is that derived? Even if there isn't a derivation of such a threshold, how is this claim substantiated?
« Last Edit: July 02, 2018, 07:01:51 PM by Bobby Shafto »

Offline edby

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Re: Empirical Validation of Perspective
« Reply #26 on: July 02, 2018, 07:09:22 PM »
This topic has brought this wiki page to my attention. I don't believe I had seen it before. What is the foundation for this claim, which has survived unedited since the page's creation:
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The sun moves constant speed into the horizon at sunset because it is at such a height that already beyond the apex of perspective lines. It has maximized the possible broadness of the lines of perspective in relation to the earth.
That’s an extraordinary claim, and confirms my interpretation of the perspective theory. According to the theory, ‘lines of perspective’ don’t just exist in the painting or on the screen: they exist in reality. So when you see the railway lines recede into the distance, they really are converging, i.e. the railway lines themselves, not just in the picture. They meet at a finite distance. Therefore it is possible for real objects to lie beyond these real perspective lines, by ‘maximizing the possible broadness of the lines of perspective’. This explains how the sun moves.

It’s an extraordinary idea. I don't know what to say.

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Offline Tom Bishop

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Re: Empirical Validation of Perspective
« Reply #27 on: July 03, 2018, 01:17:47 AM »
Tom,

You originally signed up to participate and you filled out the pre-experiment questionnaire. But you didn't follow-up and contribute with an observational input of your own.

.........

Your abandonment of this experiment and your after-the-fact critique are disappointing.

Unfortunately the steps in the instructions were not entirely clear and I fizzled out. It also seemed to be a bit pointless at the time because there was no real context. Now that this video has given context to why he wanted me to measure legos/other objects, I've given my response. If you guys wanted to ask us this question, you should have just come out and asked it.

I would have measured the legos and other objects the same as you and the author did. I don't see how me submitting another lego picture would have helped, without giving us more context on what was being tested.

It was a bit obvious that the author had some kind of agenda in mind that he was trying to set us up for -- but I was going to play along anyway. I gave you our response here in this thread. I'm not sure why I was actually needed to measure legos too? We aren't denying what was measured, so I don't know why our participation was needed?
« Last Edit: July 03, 2018, 01:32:25 AM by Tom Bishop »

Re: Empirical Validation of Perspective
« Reply #28 on: July 03, 2018, 01:37:58 AM »
It was a bit obvious that the author had some kind of agenda in mind that he was trying to set us up for -- but I was going to play along anyway. I gave you our response here in this thread. I'm not sure why I was actually needed to measure legos too? We aren't denying what was measured, so I don't know why our participation was needed?

Sadly, I was afraid of that. I knew that many people wouldn't trust me if I just told you how I think perspective works. It was my hope that you would agree to perform the test and would trust your own results. I had hoped this would create a better starting point from which to discuss how perspective works rather than the usual argument style.

As I should have suspected, people sensed that the test was likely to challenge their world views, and refused to participate. So at least for now, that approach seems to be a complete failure. The lack of trust between us runs very deep, and I've come to realize that this lack of trust is a major component of the FE movement. My "agenda" was to try to create a bridge of trust between us by cooperating on a simple experiment.

I'm glad you accept the results at least. I will point out that no FE (or undecided) who filled out the pre-experiment form already knew this material. I did get one completely blank submission, so maybe that was Tom. Maybe Tom already knew this material, but I'm somewhat hopeful that at least somebody might have learned something new.

Re: Empirical Validation of Perspective
« Reply #29 on: July 03, 2018, 05:23:20 AM »
Hi,  I only registered in order to leave a idea about a perspective experiment.  It requires you to find a really deep hole,  or digging a hole.  If you could place series of thin lines within such a hole,  and use your camera to look inside a hole,  you might find that parallel lines get closer and closer to each other. Even better if thin lines represent height.

 Holes are independant of the shape of the earth.  Whether the earth is flat or not,  there is zero curvature.

HorstFue

Re: Empirical Validation of Perspective
« Reply #30 on: July 03, 2018, 11:30:05 PM »
I assume a flat world for this:
Perspective is a projection from real world to an imaginary plane. A vanishing point does only exist in the image plane. The vanishing point is infinity in real world. Real world straight lines are also straight lines in the image plane.
So high flying objects, following a straight line parallel to the ground in real world, will also follow a straight line in the image plane, ending in the vanishing point (I deliberately avoided the word intersect).
So far so good, but now:
Distances in real world get projected to the image plane, so that these get shorter and shorter the farer away these are from the observer. They get so tiny, that near the vanishing point the tiniest stretch of line still represents a vast distance in real world.
The "flying" object will never reach the vanishing point. It will appear to get slower and slower, when approaching the vanishing point.
More probable the object will get smaller and smaller in the distance and "vanish" due to limited eye/camera/telescope resolution or atmospheric haze...  Or gets lost behind the Globe Earth curvature/horizon.

Re: Empirical Validation of Perspective
« Reply #31 on: July 04, 2018, 12:00:32 AM »
I assume a flat world for this:
Perspective is a projection from real world to an imaginary plane. A vanishing point does only exist in the image plane. The vanishing point is infinity in real world. Real world straight lines are also straight lines in the image plane.
So high flying objects, following a straight line parallel to the ground in real world, will also follow a straight line in the image plane, ending in the vanishing point (I deliberately avoided the word intersect).
So far so good, but now:
Distances in real world get projected to the image plane, so that these get shorter and shorter the farer away these are from the observer. They get so tiny, that near the vanishing point the tiniest stretch of line still represents a vast distance in real world.
The "flying" object will never reach the vanishing point. It will appear to get slower and slower, when approaching the vanishing point.
More probable the object will get smaller and smaller in the distance and "vanish" due to limited eye/camera/telescope resolution or atmospheric haze...  Or gets lost behind the Globe Earth curvature/horizon.
Yes that all sounds correct and matches what we found in the experiment... If I follow you correctly at least.

Re: Empirical Validation of Perspective
« Reply #32 on: July 05, 2018, 10:30:12 AM »
I gave you an example. You agreed with the example. You then pulled the Ancient Greek perspective theory out to tell us something about how perspective operates or scales in the distance and basically shook your finger and pointed at an equation.

Very weak.
You are constantly pulling the Ancient Greeks into this, why?
We live in the modern age and have a perfect understanding of perspective.

You however are pulling out flat earth perspective, you claim that the sun shouldn't change in size because it is beyond the apex of perspective lines, you however have no proof of this, no math to support it, it is simply a claim made by flat earthers because they can't explain why the sun doesn't change in size.

Meanwhile, you claim that we have no proof of perspective lines receding to infinity, which is just a bullocks claim as it is impossible to provide an empirical proof of this.

We know how perspective works, it is extremely simple, all you need are straight lines from the observer to the viewed objects and the angles of those lines in 3 dimensional space. From this we can calculate and simulate every observable perspective.

Now how does your perspective work?

Offline Niki4To

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Re: Empirical Validation of Perspective
« Reply #33 on: July 08, 2018, 02:38:47 PM »
I can share my artistic point of view and experience. Only lines parallel to the eyesight line are guaranteed to be seen as straight. Everything else is usually bended. It is rare to observe perfectly straight lines in real world.
For artists, notion of perspective is obtained through long practice. And at the end, it is something like a feeling about where lines should go.
In my drawings I use perspective like eyefish/360 degrees vision, but a very slighter version of it.

To determine if the horizon is a straight line, one should look to a point that is part of the horizon(the farthest distinguishable detail one can see that is supposed to "sit" down on earth surface). Looking down or up from the horizon will bend it.

(By the way, when we are looking to earth from space, a round plane earth should give us a curved horizon too. So in my own opinion, if earth is planar it has to be pretty large, so the detail-vanishing point to make the horizon appear straight. It "solves" the gravity problem too.)