Philosophy of Light Visibility (from Light: visible or invisible?)

[beecee]

34 minutes ago, Furyan5 said:

Many people believe light (electromagnetic radiation) is visible. This includes physicists, neurologists, philosophers and even some theoretical physicist. Some of the smartest people on the planet. So if you believe you can see light, you're in good company. Understanding why you can't, is a matter of ignorance, not stupidity. That's why, "The book of general ignorance" pg122, includes the following statements. Incredibly, light is invisible. If light was in fact visible, we would be blinded by a thick fog.

Hmmm is that so? How about a laser beam? 

Just to add, it maybe correct that we see the Sun as it was 8.25 minutes ago, but what we see is as much reality as it is for anyone that was on the surface of the Sun. eg: If the Sun was big enough to go S/Nova, we would still be experiencing it for 8.25 minutes....just as real as our intrepid friend on the surface of the Sun, that was blown out of existence 8.25 minutes before.  

[studiot]

The time angle makes a good point. +1

[John Cuthber]

There's a whole range of electromagnetic radiation. It covers a massive range of wavelengths. The bit of the spectrum with wavelengths between about 400 and 700 mn is called visible light.

So, what Furyan5 is claiming is that something that's definitively visible, is invisible.

Many people will see that as a problem.

 

 

44 minutes ago, Furyan5 said:

"The book of general ignorance" pg122, includes the following statements.

Incredibly, light is invisible.

The description is apt. The statement is not credible.

Why are you offering it credence?

[Furyan5]

1 hour ago, studiot said:

In case you missed my post whilst you were concocting all that, I look forward to your replies to my post, sandwiched between two of yours.

My apologies, I did miss your post.

Colors are subjective visual sensations. That includes black. Black is the sensation our brain creates when our eyes detect no light from that direction. 

I'm not familiar with those devices, but I assume they have a display screen which emits light. 

1 hour ago, elias_marquez_zoho said:

Light can be a wave or a particle, depending on the experiment you make.

Wise thinkers have been debating this since Ancient times. Democritus, Aristotle, Newton, Maxwell, etc.

I don't see the relevance.

1 hour ago, beecee said:

Hmmm is that so? How about a laser beam? 

Just to add, it maybe correct that we see the Sun as it was 8.25 minutes ago, but what we see is as much reality as it is for anyone that was on the surface of the Sun. eg: If the Sun was big enough to go S/Nova, we would still be experiencing it for 8.25 minutes....just as real as our intrepid friend on the surface of the Sun, that was blown out of existence 8.25 minutes before.  

Laser beams aren't visible, unless the beam is intense enough to reflect off air molecules, in which case you're seeing a reflection of the source. Not light. 

I don't see the point of your second statement. Nobody is saying objective reality isn't real. Merely that our perceptions don't exactly match reality.

1 hour ago, John Cuthber said:

There's a whole range of electromagnetic radiation. It covers a massive range of wavelengths. The bit of the spectrum with wavelengths between about 400 and 700 mn is called visible light.

So, what Furyan5 is claiming is that something that's definitively visible, is invisible.

Many people will see that as a problem.

 

 

The description is apt. The statement is not credible.

Why are you offering it credence?

You're using circular reasoning. Claiming light is visible, because it's called visible light. Light is most definitely not visible. This doesn't match people's understanding, so obviously they will have a problem. The point is, can they back up their beliefs?

The statement is credible, I've shown the proof. 

[studiot]

9 minutes ago, Furyan5 said:

Colors are subjective visual sensations. That includes black. Black is the sensation our brain creates when our eyes detect no light from that direction. 

I'm not familiar with those devices,

Are you saying you have never been to the cinema?

[Furyan5]

Just now, studiot said:

Are you saying you have never been to the cinema?

Obviously I have. A screen emits light towards my eyes and my brain creates images in response. I see those images. 

[studiot]

2 minutes ago, Furyan5 said:

Obviously I have. A screen emits light towards my eyes and my brain creates images in response. I see those images. 

So what colour is the screen at the cinema?

And please note that a cinema screen does not emit light.

It reflects light.

 

Edited January 25, 2018 by studiot

[Furyan5]

3 minutes ago, studiot said:

So what colour is the screen at the cinema?

And please note that a cinema screen does not emit light.

It reflects light.

 

Color doesn't exist outside our brain. Our brain creates color, depending on what wavelength of light it detects. 

5 minutes ago, studiot said:

So what colour is the screen at the cinema?

And please note that a cinema screen does not emit light.

It reflects light.

 

A television screen emits. A movie theatre screen reflects. 

[studiot]

I didn't ask where the colour exists.

I asked what colour is the screen?

 

Please don't dodge the question.

[Furyan5]

2 minutes ago, studiot said:

I didn't ask where the colour exists.

I asked what colour is the screen?

 

Please don't dodge the question.

The screen has no color.

[studiot]

5 minutes ago, Furyan5 said:

The screen has no color.

So this earlier post was incorrect then?

 

10 minutes ago, Furyan5 said:

Color doesn't exist outside our brain. Our brain creates color, depending on what wavelength of light it detects. 

 

If colour is created why does it 'not exist'?

You appear to have contradicted yourself, since you have already agreed that black is a colour.

19 minutes ago, studiot said:

Colors are subjective visual sensations. That includes black.

 

31 minutes ago, Furyan5 said:

That includes black. Black is the sensation our brain creates when our eyes detect no light from that direction

 

Edited January 25, 2018 by studiot

[Furyan5]

2 minutes ago, studiot said:

So this earlier post was incorrect then?

 

If colour is created why does it 'not exist'?

You appear to have contradicted yourself.

 

The screen has no color. The representation of the screen which you perceive subjectively has color. What part are you not getting?

[studiot]

32 minutes ago, Furyan5 said:

Colors are subjective visual sensations. That includes black. Black is the sensation our brain creates when our eyes detect no light from that direction. 

 

[Furyan5]

7 minutes ago, studiot said:

So this earlier post was incorrect then?

 

If colour is created why does it 'not exist'?

You appear to have contradicted yourself.

 

I have not contradicted myself. You can't seem to comprehend my answers.

Colors are created in the brain. They exist, in the brain. The screen does not exist in the brain. It has no color. 

Edited January 25, 2018 by Furyan5
Explained in detail

[beecee]

33 minutes ago, Furyan5 said:

Laser beams aren't visible, unless the beam is intense enough to reflect off air molecules, in which case you're seeing a reflection of the source. Not light. 

The reflection off the air molecules are photons/light...I see the light, I don't see air molecules.

Quote

I don't see the point of your second statement. Nobody is saying objective reality isn't real. Merely that our perceptions don't exactly match reality.

 

 

The Sun rose for me this morning was certainly real....just as real as the same Sun was seen as setting by someone else, some where else. They were both certainly reality. Or let me put it this way, all frames of references are as valid as any other.

 

 

6 minutes ago, Furyan5 said:

Colors are created in the brain. They exist, in the brain. 

No, colour depends on the EMR that enters the eye.

[Furyan5]

2 minutes ago, beecee said:

The reflection off the air molecules are photons/light...I see the light, I don't see air molecules.

 

 

The Sun rose for me this morning was certainly real....just as real as the same Sun was seen as setting by someone else, some where else. They were both certainly reality. Or let me put it this way, all frames of references are as valid as any other.

 

 

No, colour depends on the EMR that enters the eye.

Do you dream in color?

[studiot]

4 minutes ago, Furyan5 said:

The screen has no color. The representation of the screen which you perceive subjectively has color. What part are you not getting?

Why subjectively?

Science is objective.

This is a Science website.

Please discuss Science, not your personal misinterpretation of both the general English language and Scientific English.

 

 

1 minute ago, Furyan5 said:

I have not contradicted myself. You can't seem to comprehend my answers.

 

I have clearly demonstrated where you declared black to be a colour.

I have also clearly demonstrated where you have contradicted this.

If I can't comprehend your answers it is because they are lacking rigour and self contradictory.

 

You are the one making the claims, so it falls to you to supply the evidence, deductive or otherwise.

 

[Furyan5]

1 minute ago, studiot said:

Why subjectively?

Science is objective.

This is a Science website.

Please discuss Science, not your personal misinterpretation of both the general English language and Scientific English.

 

 

 

I have clearly demonstrated where you declared black to be a colour.

I have also clearly demonstrated where you have contradicted this.

If I can't comprehend your answers it is because they are lacking rigour and self contradictory.

 

You are the one making the claims, so it falls to you to supply the evidence, deductive or otherwise.

 

You clearly do not understand indirect realism. Get back to me once you do. 

[studiot]

Just now, Furyan5 said:

You clearly do not understand indirect realism. Get back to me once you do. 

No,  so enlighten me. (pun intended)

In particular, what does that have to do with a Physics question in a forum entitled Modern and Theoretical Physics?

 

 

[beecee]

4 minutes ago, Furyan5 said:

Do you dream in color?

Irrelevant.

Colour depends on the type of EMR that falls or enters one's eyes. What colour is an Orange in the dark? It has no colour. 

[Furyan5]

1 minute ago, studiot said:

No,  so enlighten me. (pun intended)

In particular, what does that have to do with a Physics question in a forum entitled Modern and Theoretical Physics?

 

 

The topic is whether light is visible. Vision is subjective. One can hardly answer a question regarding vision and not include subjective processes. 

Indirect realism. You do not perceive actual reality. You perceive a representation of reality, created by your brain. The world you see is a simulation, with a simulation of you in it, and your brain is the simulator. Colors exist in the simulation but not in actual reality. 

This is not a theory. It's a neuropsychological fact. 

5 minutes ago, beecee said:

Irrelevant.

Colour depends on the type of EMR that falls or enters one's eyes. What colour is an Orange in the dark? It has no colour. 

Wrong. In the dark, it's black. Air and water have no color. Light has no color. 

[studiot]

On 15/11/2017 at 11:16 PM, Furyan5 said:

It's light which makes objects visible.

You claimed that the only way for us to see an image, regardless of where it resides or the mechanism of generating that image, is using light.

Yet you then tell me that I can see a black dog, because there is no light.

This is a flat out contradiction and no amount of hand waving and burying it in obscure language will alter that.

You told me that a cinema screen emits light.

That was flat out wrong.

 

[Furyan5]

5 minutes ago, studiot said:

You claimed that the only way for us to see an image, regardless of where it resides or the mechanism of generating that image, is using light.

Yet you then tell me that I can see a black dog, because there is no light.

This is a flat out contradiction and no amount of hand waving and burying it in obscure language will alter that.

You told me that a cinema screen emits light.

That was flat out wrong.

 

I said no such thing. What I said is that "visible light" is the light which makes objects visible. I never said it's the only way we can see something. Have you heard of a silhouette? We can perceive a shape through contrast with it's surroundings. 

Yes, I used emit instead of reflect. That was wrong. 

[beecee]

1 hour ago, Furyan5 said:

Wrong. In the dark, it's black. Air and water have no color. Light has no color. 

It is you that is wrong. Black by definition is the absence of colour. Water in general is transparent and light is visible by definition and we call that the visible spectrum. Put our Orange that we normally see as Orange, under a pure say green part of the visible spectrum, and the Orange wlil not be Orange but purple from memory. 

Edited January 25, 2018 by beecee

[studiot]

1 minute ago, Furyan5 said:

I said no such thing. What I said is that "visible light" is the light which makes objects visible. I never said it's the only way we can see something. Have you heard of a silhouette? We can perceive a shape through contrast with it's surroundings. 

Yes, I used emit instead of reflect. That was wrong. 

Yes indeed we can perceive a shape through contrast and that is how we can 'see' a black dog on a white screen.

But what if the dog was a real black dog running across the podium, in front of the screen?

We would still see a black dog running across the screen.

 

Anyway let us move on.

 

Let us examine your claim that the image colour we see is independent of light and only a function of the processes within our heads.

Let us do that in  a proper scientific manner in accorance with the rules of evidence.

So  let us consider a blank cinema screen and a projectionist with light projector equipped with a range of coloured filters.

Let us watch as the projectionisd projects a circle of light onto the screen.

We observe a red disk, then a green one, then a blue one and so on.

Your claim fails at this point because the only change that has been made is by the projectionist.

We see a red disk and can identify this later with the red filter being in place and can do this repeatedly.

We never see a blue disk with that red filter in place, and similarly with the blue and green filters.

So there must be something about the light from the red filter that is different from the light from the blue filter, that cuases our internal imaging system to note a red or blue disk.

By definition this light is defined as red light and the blue filter light as blue light and so on.

 

That is scientific deduction in action as opposed to someone wildly asserting vague nonsense.