Light: visible or invisible?

[swansont]

54 minutes ago, Furyan5 said:

 No it's not. The object reflecting the light is visible. Light is detectable. Big difference. Some eyes detect light while the person sees nothing. 

Depends on how you've defined the terminology. Someone could say, "i see" as a response to your statement, because in that use, it means to understand, and they would not be wrong. Stop pretending that everyday language has such precise definitions. It doesn't.

Most of the time, when we say we see something, it's an object; it has a defined shape and light is reflecting off of it (or occasionally emitted by it; you can see a hot burner on a stove) But you can also say you see the sky from the scattered light, even though the sky has no real defined shape — it's everywhere if you're on earth (though blocked by the earth in some places) and you can't gauge the depth of it from what you see.

 

 

1 hour ago, Furyan5 said:

 Because? Photons are not visible? 

Yes, we know.

Is a 2-D object* visible? How about when viewed edge-on?

 

*or a very thin object, very far away.

[Furyan5]

37 minutes ago, studiot said:

 

Yes thank you, I have never not 'got it'.

That is why I credited you with introducing the end user viewpoint (the brain) from the outset and did not immediately take issue with this view.

In fact my first response was to assert that although  you wish to simplify, Nature is that much more complicated and will thwart you.

You must have accepted this at some point because you yourself said that the meaning of words crucial to the discussion depends upon the context.

My problem with the simple statement that what you see is the model constructed by the brain is that this model is constructed not only from the visual information received by the eyes but also from other information known to the brain and personal directives and controls guiding the creation of the mental model. Some of this additional information is voluntary, some is involuntary.

In contrast the image on the retina is as faithful a reproduction as the laws of Nature allow (although there are also issues with this that we have not discussed).

No image is formed on the retina. Each cone on the fovia is connected to a single ganglion which connects to an individual optic nerve. The information from the retina is digitized, not sent as a complete image. Image processing occurs only in the visual cortex. 

Your eyes see nothing. NOTHING! 

36 minutes ago, swansont said:

Depends on how you've defined the terminology. Someone could say, "i see" as a response to your statement, because in that use, it means to understand, and they would not be wrong. Stop pretending that everyday language has such precise definitions. It doesn't.

I see what you mean is a metaphor. We use it to say that we understand or comprehend. Metaphorically speaking, we can 'see the light', but that's not what this question is about. We're specifically asking, 'Can we visually perceive photons?'. 

And the answer is NO! WE CAN'T! 

36 minutes ago, swansont said:

Most of the time, when we say we see something, it's an object; it has a defined shape and light is reflecting off of it (or occasionally emitted by it; you can see a hot burner on a stove) But you can also say you see the sky from the scattered light, even though the sky has no real defined shape — it's everywhere if you're on earth (though blocked by the earth in some places) and you can't gauge the depth of it from what you see.

The sky only exists as a virtual construct of the brain. We 'see' blue, because our eyes detect 400nm light coming from that direction. 

36 minutes ago, swansont said:

Is a 2-D object* visible? How about when viewed edge-on?

 

*or a very thin object, very far away.

Obviously not. 

 

[studiot]

I see you want to quibble with definitions again, rather than consider the substance of the discussion.

Are you familiar with Rod Stewart and his song My Mind's Eye?

Edited January 29, 2018 by studiot

[swansont]

32 minutes ago, Furyan5 said:

 I see what you mean is a metaphor. We use it to say that we understand or comprehend. Metaphorically speaking, we can 'see the light', but that's not what this question is about. We're specifically asking, 'Can we visually perceive photons?'. 

And the answer is NO! WE CAN'T! 

Of course we can. They don't always form an image. We don't perceive them as a shape.

You've now defined seeing as visually perceiving, but isn't that the same as detecting?

Can we see small things, like atoms? Can we see a fluorescent vapor, like a neon light?

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The sky only exists as a virtual construct of the brain. We 'see' blue, because our eyes detect 400nm light coming from that direction. 

What about if you are outside of the earth's atmosphere. Is the atmosphere a virtual construct of the brain then?

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Obviously not. 

So invisibility is not some inherent property. Looking at photons from the side is not so different from looking at this thin object from the side, so why is this obvious due to one reason (geometry), but when applied to photons it's because they're inherently invisible, rather than due to geometry?

[Furyan5]

1 hour ago, swansont said:

Of course we can. They don't always form an image. We don't perceive them as a shape.

You've now defined seeing as visually perceiving, but isn't that the same as detecting?

No it's not. There are people who's eyes can detect light but they see nothing.

1 hour ago, swansont said:

Can we see small things, like atoms? Can we see a fluorescent vapor, like a neon light?

We see the vapour, not light.

1 hour ago, swansont said:

What about if you are outside of the earth's atmosphere. Is the atmosphere a virtual construct of the brain then?

Yes. Everything you perceive visually is the construct. We only perceive the construct. As I have repeatedly said, it's crucial that you 'get this'. Many people 'say they get this' then turn around and say 'the eye sees' or 'the image formed in the eye'. Statements like these show that 'you don't get it'. THE EYE SEES NOTHING, IT ONLY DETECTS LIGHT!

1 hour ago, swansont said:

So invisibility is not some inherent property. Looking at photons from the side is not so different from looking at this thin object from the side, so why is this obvious due to one reason (geometry), but when applied to photons it's because they're inherently invisible, rather than due to geometry?

From any angle a photon is size-less. From any angle a photon is invisible. We DETECT photons which PHYSICALLY strike our retina. We FEEL them. This is a PART of the visual system, whereby we 'see' OBJECTS. 

Please read and absorb what I'm saying. I completely understand that someone you highly respect once told you that we can see light. Even Einstein was wrong about some things. As a scientist it's your duty to view evidence objectively, not cling to a belief despite obvious evidence to the contrary. My opening statement in my debate is that the belief that light is visible IS NOT a sign of stupidity. It's a sign of ignorance. Many great  (in my opinon) minds, believe that visible light is visible. 

 

1 hour ago, studiot said:

I see you want to quibble with definitions again, rather than consider the substance of the discussion.

Are you familiar with Rod Stewart and his song My Mind's Eye?

Are you familiar with the poem by Emily Dickinson,

The brain is bigger than the sky,

For put them side by side,

The one, the other will contain, (The sky fits inside the brain)

With ease and you beside. (The representation of reality includes a representation of you, in it.)

Emily Dickinson understood indirect realism. 

7 minutes ago, Furyan5 said:

 

Are you familiar with the poem by Emily Dickinson,

The brain is bigger than the sky,

For put them side by side,

The one, the other will contain, (The sky fits inside the brain)

With ease and you beside. (The representation of reality includes a representation of you, in it.)

Emily Dickinson understood indirect realism. 

Please, 'get it'. The eye can't see.

The eye is nothing but an antenna. Detecting EM waves and converting them to electrical impulses. Two radar dishes, set to detect 700nm to 400nm wavelengths of light. 

[swansont]

18 minutes ago, Furyan5 said:

 We see the vapour, not light.

We can't see the vapor, or the gas, when the switch is turned off. It's just a collection of atoms.  Can we see individual atoms?

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Yes. Everything you perceive visually is the construct. We only perceive the construct. As I have repeatedly said, it's crucial that you 'get this'. Many people 'say they get this' then turn around and say 'the eye sees' or 'the image formed in the eye'. Statements like these show that 'you don't get it'.

Statements like this show I am not convinced.

But if everything is a construct, then according to you we see nothing. (Not that this is physics, which is what we are supposed to be discussing) 

Quote

THE EYE SEES NOTHING, IT ONLY DETECTS LIGHT!

But now that you've shouted, I totally agree.  /sarcasm

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From any angle a photon is size-less. From any angle a photon is invisible. We DETECT photons which PHYSICALLY strike our retina. We FEEL them. This is a PART of the visual system, whereby we 'see' OBJECTS. 

I can cite examples that contradict your claim that the photon is size-less, if you are interested in learning some physics. 

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Please read and absorb what I'm saying.

This isn't a lecture. Disagreeing is not the same as not comprehending.

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I completely understand that someone you highly respect once told you that we can see light. Even Einstein was wrong about some things. As a scientist it's your duty to view evidence objectively, not cling to a belief despite obvious evidence to the contrary. My opening statement in my debate is that the belief that light is visible IS NOT a sign of stupidity. It's a sign of ignorance. Many great  (in my opinon) minds, believe that visible light is visible. 

When Einstein (or anyone else, regarding scientific principles) was shown to be wrong it was because evidence was presented that showed a model to be incorrect, or some flaw in a derivation. Something much more than simply shouting a contrary position.

[Furyan5]

1 hour ago, swansont said:

We can't see the vapor, or the gas, when the switch is turned off. It's just a collection of atoms.  Can we see individual atoms?

Statements like this show I am not convinced.

But if everything is a construct, then according to you we see nothing. (Not that this is physics, which is what we are supposed to be discussing) 

No. We see the simulation created by our brain. We can't see objective reality, that's true, but we can subjectivity perceive the visual representation of it. This allows us to interact with our unperceivable reality. We 'see' predators, food, potential mates, etc. This gives us an evolutionary advantage. 

But now that you've shouted, I totally agree.  /sarcasm

I can cite examples that contradict your claim that the photon is size-less, if you are interested in learning some physics. 

This isn't a lecture. Disagreeing is not the same as not comprehending.

When Einstein (or anyone else, regarding scientific principles) was shown to be wrong it was because evidence was presented that showed a model to be incorrect, or some flaw in a derivation. Something much more than simply shouting a contrary position.

The cones in the fovia send information in a digitized format. Neurological fact. It confirms the philosophical hypothesis. Image processing (and visual perception) occurs in the visual cortex. 

There's your proof. 

 

52 minutes ago, Furyan5 said:

 

Proving indirect realism is the simple part. Getting people to comprehend indirect realism is the difficult part. It's not that our eyes see a shape, and our brain tells us its a tree. Our brain creates the shape you see. No perception at all occurs in the eyes. I'm not shouting. I'm highlighting the important bits. 

52 minutes ago, Furyan5 said:

 

Proving indirect realism is the simple part. Getting people to comprehend indirect realism is the difficult part. It's not that our eyes see a shape, and our brain tells us its a tree. Our brain creates the shape you see. No perception at all occurs in the eyes. I'm not shouting. I'm highlighting the important bits. 

 

52 minutes ago, Furyan5 said:

 

Proving indirect realism is the simple part. Getting people to comprehend indirect realism is the difficult part. It's not that our eyes see a shape, and our brain tells us its a tree. Our brain creates the shape you see. No perception at all occurs in the eyes. I'm not shouting. I'm highlighting the important bits. 

http://www.cycleback.com/eyephysiology.html

[dimreepr]

7 minutes ago, Furyan5 said:

The cones in the fovia send information in a digitized format. Neurological fact. It confirms the philosophical hypothesis. Image processing (and visual perception) occurs in the visual cortex. 

There's your proof. 

Where do the cones get the information?

8 minutes ago, Furyan5 said:

Proving indirect realism is the simple part. Getting people to comprehend indirect realism is the difficult part. It's not that our eyes see a shape, and our brain tells us its a tree. Our brain creates the shape you see. No perception at all occurs in the eyes. 

 

No one has suggested otherwise. 

“I am so clever that sometimes I don't understand a single word of what I am saying.”― Oscar Wilde

[Furyan5]

1 minute ago, dimreepr said:

Where do the cones get the information?

They get it from the light they detect (not see) obviously. 

No one has suggested otherwise. 

Yes they have. Just because you 'get it' doesn't mean everyone 'gets it'. If they truly 'got it' I wouldn't have to repeat myself 

“I am so clever that sometimes I don't understand a single word of what I am saying.”― Oscar Wilde

 

[dimreepr]

Just now, Furyan5 said:

Yes they have. Just because you 'get it' doesn't mean everyone 'gets it'. If they truly 'got it' I wouldn't have to repeat myself 

Please, show me 'a' post, in either thread, that suggests the eye perceives.

[Eise]

I am wondering if people here disagree on some physical or biological facts, or just the semantics of the the verb 'to see'. If the latter, is such a heavy discussion necessary when all agree about the facts? 

[dimreepr]

5 minutes ago, Eise said:

I am wondering if people here disagree on some physical or biological facts, or just the semantics of the the verb 'to see'. If the latter, is such a heavy discussion necessary when all agree about the facts? 

2

No, but it's often the case that understanding hinges on semantics rather than facts.

[Furyan5]

18 minutes ago, Eise said:

I am wondering if people here disagree on some physical or biological facts, or just the semantics of the the verb 'to see'. If the latter, is such a heavy discussion necessary when all agree about the facts? 

If the fact we agree on is 'that we can't see light' (visually perceive photons), then yes. 

[dimreepr]

11 minutes ago, dimreepr said:

No, but it's often the case that understanding hinges on semantics rather than facts.

Case in point:

2 minutes ago, Furyan5 said:

If the fact we agree on is 'that we can't see light' (visually perceive photons), then yes. 

 

[swansont]

53 minutes ago, Furyan5 said:

The cones in the fovia send information in a digitized format. Neurological fact. It confirms the philosophical hypothesis. Image processing (and visual perception) occurs in the visual cortex. 

There's your proof. 

I don't recognize this as physics.

 

27 minutes ago, Eise said:

I am wondering if people here disagree on some physical or biological facts, or just the semantics of the the verb 'to see'. If the latter, is such a heavy discussion necessary when all agree about the facts? 

Furyan5 has seemingly rejected the notion that this is semantics, or that neurology isn't physics.

[Furyan5]

2 minutes ago, dimreepr said:

Case in point:

 

Exactly, if a distinction between 'detect' and 'see' is not made, the answer changes. I have shown that an eye can detect without the subject seeing. Detection is not seeing, therefore, we can't see light. 

[swansont]

Just now, Furyan5 said:

Exactly, if a distinction between 'detect' and 'see' is not made, the answer changes. I have shown that an eye can detect without the subject seeing. Detection is not seeing, therefore, we can't see light. 

How can the answer change if this isn't semantics?

[koti]

Eyes are the sensors, the brain is the processor. "Seeing" occurs when both work together to create an image in our brain. The principle is basically the same as with any device which senses and processes an image. Film or still cameras work under the same basic principle, a sensor captures light and a CPU processes the captured light to form an image.

[dimreepr]

1 minute ago, koti said:

Eyes are the sensors, the brain is the processor. "Seeing" occurs when both work together to create an image in our brain. The principle is basically the same as with any device which senses and processes an image. Film or still cameras work under the same basic principle, a sensor captures light and a CPU processes the captured light to form an image.

Who knew it was that simple? 

[Furyan5]

21 minutes ago, swansont said:

I don't recognize this as physics.

 

Furyan5 has seemingly rejected the notion that this is semantics, or that neurology isn't physics.

Actually I fully agree. Vision is a neurological process. The question 'is light visible' is a question which physicists are ill equipped to answer. The question doesn't belong here. 

[dimreepr]

2 minutes ago, Furyan5 said:

Actually I fully agree. Vision is a neurological process. The question 'is light visible' is a question which physicists are ill equipped to answer. The question doesn't belong here. 

2

But the answer does...

[koti]

5 minutes ago, dimreepr said:

Who knew it was that simple? 

It really is. The rest is semantics as noted by posts above - does bacteria „see” when capable only of distinguishing between presence and lack of light or does Michael Angelo „see” working on fresques in the sistine chapel. Not an interesting question, at least not on a Monday when my gd Win10 keeps upgrading not letting me work.

[Furyan5]

2 minutes ago, dimreepr said:

But the answer does...

Physicists aren't equipped to answer and they reject any non-physics answers. 

Just now, Furyan5 said:

Physicists aren't equipped to answer and they reject any non-physics answers. 

But by now I'm sure the answer is obvious. Like it or not.

Furyan out.

[dimreepr]

4 minutes ago, Furyan5 said:

and they reject any non-physics answers. 

No shit Sherlock...

[swansont]

16 minutes ago, Furyan5 said:

Physicists aren't equipped to answer and they reject any non-physics answers. 

More precisely, physicists aren't equipped to answer in a neurological context. But we don't have a neurological context. This would not be the first instance of physics (or some discipline) and  <some other discipline> giving different answers because of the context of their respective fields.

But you keep trying to bring neurology (and philosophy) to a physics discussion.