Furyan5

9 minutes ago, koti said:

Theres really no way of leading a coherent discussion with someone who yet again is incapable of using the quoting system on this site. 

Light is visible because it is required for the process of sight to take place.

Required to make objects visible. We need light to see objects. It's the objects which are visible, not the light. 

Please read that...

4 minutes ago, Strange said:

By falling on the retina.

I can't believe that this discussion over the semantics of "visible", "seeing", etc has lasted for 17 pages. Bizarre.

 

True. 17 pages and people still can't tell the difference between detection (when light falls on the retina) and seeing  (when we perceive the minds model of an object). Detecting something that (falls on you) is called feeling, not seeing. 

I know some people are "slow", but this is bordering on ridiculous. 

4 minutes ago, koti said:

I never claimed that detection is sight. This what you are doing here is a classic strawman argument - please stop doing that.

What scares me is your asinine and infantile statements which lead to confusion like this one here:

Light does not need to emit or reflect light in order for objects to emit or reflect light.

Please read that as many times as you need untill it sinks in.

So how can light be visible?

Please read that as many times as you need until it sinks in... 

Just now, studiot said:

 

Do you always respond with a barrage of personally directed invective?

 

 

Do you always avoid answering questions?

2 hours ago, studiot said:

Strictly speaking that is true since the original question was

Is light visible or invisible ?

When this question is applied to anything whatsoever it means

Is that thing capable of being seen or not capable of being seen?

Now although these two qualities are mutually exclusive and complementary they also possess a fundamental difference.

If something is capable of being seen it does not matter whether or not it is actually seen.
That is it does not matter if there is something or someone there to perform the seeing activity.
Nor does it matter if the physical agency by which the seeing activity is performed is present or not.
All that matter is that if both those conditions are met then seeing could happen.
So, for instance, to see an object that is in the dark all we need to do may be to switch on the light.
But we may also need to satisfy further conditions.

In those circumstances, what colour we see is irrelevant we either see or we don't.
 

On the other hand if something has the quality that it is incapable of being seen then there is nothing we can do to the conditions or the object to see it.
That is the definition of the word incapable (or invisible).

 

Having said that, the OP is long gone and many have a clear desire to widen the discussion, something the mods permit in such circumstances.

So the question then arises, can we put together a coherent and rational model compatible with all the expressed conflicting views?

 

My answer is yes such a model is possible, although it might suprise some.

 

Studiot suggested this. I think it's a brilliant idea. I responded with this. (

Perfect, so let's do that. What properties make things visible?

1: they must reflect or emit light. Does light do either? No!

2: they must be big enough to be seen. How big is a photon? No size.

3: they must be slow enough to be seen. How fast is light? It's the fastest thing in the universe.

Any one of these is enough to make an object invisible. Yet some people adamantly cling to the belief that we can see light.)

Can someone respond please! If I'm wrong somehow, show me. 

If you can't, don't bother responding. 

This myth is busted!

Just now, koti said:

Anyone who has basic knowledge of the relevant subjects at hand (physics, human physiology, color perception) has decided long ago that this disussion is null. Not being able to reconcile useless semantics with physics is not an impasse. 

No. Ignoring cold hard facts in favour of conventional beliefs is an impasse. None so blind as those who do not want to see. 

What scares you? Being wrong? Even Einstein was wrong on occasion. The world won't end if you admit that detection is not sight. 

"Why Mr Anderson, why? Why do you persist with this delusion? The 'visible light spectrum' is the range of light 'by which humans see'. Not the range of light we see. It's called visible light because 'it makes objects visible'. Accept it. You we're wrong. We can't see light. 

1 hour ago, studiot said:

But that view is seriously inadequate as it only describes part of the situation.

Hence the impasse.

'Cough' Did you miss the rest of it? Or are you ignoring it because the facts don't match up with your current beliefs? This is the power of preconception. You have no answer, so your mind blocks it out. 

I'll repeat it. 

Perfect, so let's do that. What properties make things visible?

1: they must reflect or emit light. Does light do either? No!

2: they must be big enough to be seen. How big is a photon? No size.

3: they must be slow enough to be seen. How fast is light? It's the fastest thing in the universe.

Any one of these is enough to make an object invisible. Yet some people adamantly cling to the belief that we can see light. 

8 hours ago, Rob McEachern said:

That is not true. Color is entirely constructed, within your brain, from measurements of intensities. In other words, it is constructed from counting the number of photons received in three different frequency bands (in normal humans). And these photon counts are modified (such as via white balance in a digital camera) to make the color of every perceived object, depend not just on the properties of the object in question, but on all the surrounding objects as well (in an attempt to account for the spectrum of the illuminators). This last point was the reason for my first post above ; if you prevent the visual system from "seeing" the surrounding scene, it may dramatically change the color the brain assigns to an object within the scene.

You're almost there. You understand that colors only exist in the mind. Now you only have to realize that the 'perceived objects' are also constructs of the mind. The reality you perceive is not outside you. You see the construct. Your whole life you only perceive the construct. 

This is beyond the others, but I believe it's within your grasp, even if you disagree at first. 

4 minutes ago, studiot said:

Strictly speaking that is true since the original question was

Is light visible or invisible ?

When this question is applied to anything whatsoever it means

Is that thing capable of being seen or not capable of being seen?

Now although these two qualities are mutually exclusive and complementary they also possess a fundamental difference.

If something is capable of being seen it does not matter whether or not it is actually seen.
That is it does not matter if there is something or someone there to perform the seeing activity.
Nor does it matter if the physical agency by which the seeing activity is performed is present or not.
All that matter is that if both those conditions are met then seeing could happen.
So, for instance, to see an object that is in the dark all we need to do may be to switch on the light.
But we may also need to satisfy further conditions.

In those circumstances, what colour we see is irrelevant we either see or we don't.
 

On the other hand if something has the quality that it is incapable of being seen then there is nothing we can do to the conditions or the object to see it.
That is the definition of the word incapable (or invisible).

 

Having said that, the OP is long gone and many have a clear desire to widen the discussion, something the mods permit in such circumstances.

So the question then arises, can we put together a coherent and rational model compatible with all the expressed conflicting views?

 

My answer is yes such a model is possible, although it might suprise some.

 

Perfect, so let's do that. What properties make things visible?

1: they must reflect or emit light. Does light do either? No!

2: they must be big enough to be seen. How big is a photon? No size.

3: they must be slow enough to be seen. How fast is light? It's the fastest thing in the universe.

Any one of these is enough to make an object invisible. Yet some people adamantly cling to the belief that we can see light. 

Logical? I think not.

9 minutes ago, koti said:

Its exactly that, there is no contradiction. How much longer will it take you to understand that when we see an object, we only see light. We see objects only by perceiving light which bounces off of them or is being emitted by them. Oranges are invisible without light, you actually wrote something which makes sense, too bad you think its incorrect. 

How much longer will it take you to realize the we 'see' objects, when our eyes 'detect' light. We perceive the object, we infer the light. 

Detecting light is part of the visual process but the purpose of vision is to allow us to see things. Seeing things gives us an evolutionary advantage. 

Our retina detects light that strikes it. Seeing is the ability to perceive an object without making physical contact with the object. If light must 'strike' our eyes to be detected, that is not seeing. That's feeling. 

We detect light. We see objects. 

I will say this only once. You're confusing the Orange you see (which is the mind model) with the Orange (outside our bodies) which reflects light. The mind only creates the mind model if our eyes detect (not see) light coming from the 'outside' orange. 

If, as you claim, we see light, then we don't see objects. Only light is visible and objects are invisible. According to your claim, oranges are invisi ble. 

This is the contradiction 

13 minutes ago, beecee said:

As is your rather pedant philosophical take just your opinion.

 

AGREED. 

Agreed, but my opinion doesn't contradict itself. My opinion doesn't claim we can see size-less, colourless and incredibly fast EMR.

1 minute ago, koti said:

The only reason that the human eye can see the visible spectrum is because specific wavelengths of light stimulate the retina in the human eye. The rest is overthinking or nonsense. 

Opinion. Again.

11 minutes ago, studiot said:

 

I think you are the only person who agrees this.

 

 

Actually, you're the only one who disagrees and thereby, holding everyone back.

You're excused!

So, since we all agree that light has no color, how can we see it?

1 minute ago, studiot said:

 

So you are saying that the system in the human eye can distinguish between two waves one of 540 nm and one of 541nm ?

540nm is the wavelength, not the amplitude.

Just now, StringJunky said:

Yes, but the object pre-filters what comes first and then the eye-brain does what it does with that.

Correct. Technically, color is the property of the object, which causes it to absorb or reflect certain wavelengths of light. What we call colors, like red, yellow and green, are actually hues. So objects have colors and we perceive hues.

1 minute ago, StringJunky said:

Or: Orange is a result of the reflective selective properties of the object

Or, orange is a visual sensation created by our brain 

Just now, Rob McEachern said:

In normal humans. Many other creatures have different numbers. Mantis shrimp have 16.

Many is shrimps lack the mental capacity to perceive as many colors as humans. They actually see no better than dogs.

6 minutes ago, beecee said:

Wow!! Are you trying to be funny? Talk  about philosophical pedantic nonsense!

Let me sum it up for you...We see light, which we call the EMS. Black is the absence of light/colour, or a property of the object absorbing all of the EMS.

And while in a technical sense, it is really not appropriate to refer to light as being colored. Light is simply a wave with a specific wavelength or a mixture of wavelengths; it has no color in and of itself. An object that is emitting or reflecting light to our eye appears to have a specific color as the result of the eye-brain response to the wavelength. 

http://www.physicsclassroom.com/class/light/Lesson-2/Visible-Light-and-the-Eye-s-Response

Agreed.

That's your opinion. Nothing more, nothing less. 

3 minutes ago, Rob McEachern said:

However, the converse is not true. A specific color can be produced by combinations of several wavelengths, as when red and green combine to form yellow.

And, there is no pink wavelength 

11 minutes ago, beecee said:

beecee says our eyes detect/interpret/see light and the exact nature of that light is interpreted as a specific colour. Again, if we have no EMS, we have no colour or black.

Your claims so far seem rather philosophical and rampant, rather then observational physics.

 

Would a quote from Isaac Newton himself convince you? Optiks 1701. "For the waves themselves are not coloured."

2 minutes ago, beecee said:

http://www.physicsclassroom.com/class/light/Lesson-2/Visible-Light-and-the-Eye-s-Response

Visible Light Spectrum

The focus of Lesson 2 will be upon the visible light region - the very narrow band of wavelengths located to the right of the infrared region and to the left of the ultraviolet region. Though electromagnetic waves exist in a vast range of wavelengths, our eyes are sensitive to only a very narrow band. Since this narrow band of wavelengths is the means by which humans see, we refer to it as the visible light spectrum. Normally when we use the term "light," we are referring to a type of electromagnetic wave that stimulates the retina of our eyes. In this sense, we are referring to visible light, a small spectrum from the enormous range of frequencies of electromagnetic radiation. This visible light region consists of a spectrum of wavelengths that range from approximately 700 nanometers (abbreviated nm) to approximately 400 nm. Expressed in more familiar units, the range of wavelengths extends from 7 x 10^-7 meter to 4 x 10^-7 meter. This narrow band of visible light is affectionately known as ROYGBIV.

As mentioned in the first section of Lesson 2, our eyes are sensitive to a very narrow band of frequencies within the enormous range of frequencies of the electromagnetic spectrum. This narrow band of frequencies is referred to as the visible light spectrum. Visible light - that which is detectable by the human eye - consists of wavelengths ranging from approximately 780 nanometer (7.80 x 10^-7 m) down to 390 nanometer (3.90 x 10^-7 m). Specific wavelengths within the spectrum correspond to a specific color based upon how humans typically perceive light of that wavelength. The long wavelength end of the spectrum corresponds to light that is perceived by humans to be red and the short wavelength end of the spectrum corresponds to light that is perceived to be violet. Other colors within the spectrum include orange, yellow, green and blue. The graphic below depicts the approximate range of wavelengths that are associated with the various perceived colors within the spectrum.

Thank you. Read carefully. It says "Since this narrow band of wavelengths is the means by which humans see, we refer to it as the visible light spectrum". It's not the light we see. It's the light which allows us to see. 

need more?

15 minutes ago, studiot said:

Magnanimous of you.

How is that supposed to work?

You ask, and I answer. 

I'm talking to three people. Only one comment is directed at you.

33 minutes ago, koti said:

The only truth that comes from your post is the fact that you’ve been on this forum for about 4 months and you still haven’t mastered the subtle art of quoting someone. Oh, and nobody is saying that the eyes interpret anything. 

 

Lol really? BeeCee says exactly that. Scroll up a bit. 

Btw, I never claimed colors are the product of a single wavelength. I claimed that light itself has no color. 

1 minute ago, studiot said:

If you can only respond to one point at a time why do you post multiple points in your posts.?

one question.

I'm sorry I can't respond to your second point (as requested) in your last post until we finish this one.

I can only respond to one. You can respond to many. 

2 minutes ago, studiot said:

 

 

I did read the article and I liked it better than I thought I would.

Would you like me to extract and display the exact passage that conflicts with your absolute declaration that a colour corresponds to a single wavelength?

Don't patronise me, they were correct, you were wrong.

 

Please also answer my other questions/points.

 

Yes, please show me where you see this contradiction? 

And ask one question at a time. 

2 minutes ago, studiot said:

A pity this conflicts with the' high school' explanation you posted a link to.

You also needed to introduce several new undefined words to offer your explanation.

sensation, detect, perceive.

Why are these better than Eise's see1 and see2?

 

There is also a logical difficulty with placing all the meaning of vision in the brain.

That is a non defective eye can only create a faithful retinal image of the received light with nothing added or taken away.

 

The brain both adds and subtract extraneous material to the image it creates.

 

I don't understand what you mean by reflecting orange light in all directions
Please explain.

 

 

 

Read the article again. It says exactly the same thing. Maybe you'll listen to a physicist.https://youtu.be/fQczp0wtZQQ

9 minutes ago, koti said:

The only truth that comes from your post is the fact that you’ve been on this forum for about 4 months and you still haven’t mastered the subtle art of quoting someone. Oh, and nobody is saying that the eyes interpret anything. 

 

Lol really? BeeCee says exactly that. Scroll up a bit. 

https://www.scientificamerican.com/article/illusory-color-andamp-the-brain-2008-05/

1 minute ago, koti said:

 

 

Wrong. Our eyes detect 630nm wavelength light and send electrochemical impulses to our brains visual cortex where our brain creates the sensation orange. Our eyes see nothing. They detect, they don't perceive. 

If 630nm light was orange, we would see it being reflected by the Orange in all directions.

I know it's hard to let go of a preconception. It blinds you to the truth.

28 minutes ago, beecee said:

I'm saying that certain parts of the EMS, that is visible to the eye, is interpreted as a specific colour. If there is no EMS for the eye to interpret, there is no colour and we see blackness.  If the EMS is specifically at another wavelength, the eye will interpret that differently. I believe that was pretty clear in my previous post.

The eye serves just one purpose. It converts light into an electrochemical signal. It doesn't interpret anything. It doesn't perceive anything. 

http://www.dailymail.co.uk/sciencetech/article-3093457/Does-colour-exist-BRAIN-Book-argues-simply-construct-mind.html

3 minutes ago, koti said:

An orange does not radiate anything unless it spent time in proximity of something radio active. An orange reflects light which we perceive as ~630nm color we call „orange”

I'm talking about an orange in direct sunlight. According to you, it reflects Orange light right?

10 minutes ago, koti said:

What?! You’re dragging in Kant and metaphysics into this thread now? 

What? 

If light had color, wouldn't you see Orange light radiating away from an orange in all directions?

Why is only the light coming towards you orange?