The Instigator
Furyan5
Con (against)
Tied
0 Points
The Contender
KostasT.1526
Pro (for)
Tied
0 Points

Is light visible or invisible?

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Voting Style: Open Point System: 7 Point
Started: 11/18/2017 Category: Science
Updated: 8 months ago Status: Post Voting Period
Viewed: 1,304 times Debate No: 105159
Debate Rounds (3)
Comments (60)
Votes (0)

 

Furyan5

Con

The general belief is that light, specifically visible light, is visible. Surprisingly, the book of general ignorance states that light is actually invisible. I tend to agree.

Would anyone care to debate the issue?
Only one rule. A dictionary definition can't be used as proof itself.

https://books.google.co.za...
KostasT.1526

Pro

Hello, and thank you for the debate. I contend that light in the visible spectrum is, indeed, visible.

Definitions:
My opponent did not propose any definitions, so I will instead:
1. Visible (main definitions) [1]:
[viz-uh-buhR01;l]
adjective
a. That can be seen; perceptible to the eye
b. Apparent; manifest; obvious
2. Visible spectrum of light:
The frequencies of an electromagnetic wave ranging from 430 to 770 THz [2]

Arguments:
1. The light of the visible spectrum is visible, for it meets the requirements the definition of "visible" sets; it is perceived by the eye. I cannot think of any way to justify my thesis more than this, especially since my opponent has not yet presented their arguments. Therefore, let us proceed to round 2.

Sources:
[1] Dictionary.com, "visible"
http://www.dictionary.com...
[2] Visible spectrum of light, Wikipedia
https://en.m.wikipedia.org...
Debate Round No. 1
Furyan5

Con

Thank you pro.

Your definition of visible being perceptible to the eye is inaccurate. Vision occurs in the visual cortex of the brain. View link. No perception occurs in the eye itself. The eye does detect light, however, it only detects light that actually strikes the retina. Detection through physical contact falls in the category of touch, not sight. Our eyes feel when light strikes them. Light is the information carrier and our brain interprets the information to produce visual perceptions. We do not see the world with our eyes, we see a visual representation of the world, created by our brain. What we see, are the objects from which the light originates.

Light has no color, isn't made of physical matter and moves at "the speed of light". Any one of these factors would render an object invisible. Air is colourless. We can't see it, but we can feel the wind. We can't see electrons with the naked eye because they are too small, photons have nothing to see. We can't see a bullet flying through the air and light is a million times faster. To actually see light, it would have to give off light, which is impossible as light is a fundamental particle. If light did actually give off light and become visible, we would be blinded by a thick, multicolored fog of light.

So to summarize, our eyes detect light that strikes it but not light that passes in front of us. So we feel light with our eyes, we don't see light. We see through our eyes in the brains visual cortex. We see the objects from which the light originates. Not the light itself.

http://www.cycleback.com...
KostasT.1526

Pro

My opponent has made several mistakes in their attempts to prove that light is not visible. I shall examine their arguments one by one.

"Your definition of visible being perceptible to the eye is inaccurate."
The definition I cited, is in fact representative of the definitions most of the best dictionaries worldwide would provide, and thus is quite accurate [1].
"Vision occurs in the visual cortex of the brain. View link. No perception occurs in the eye itself. The eye does detect light, however, it only detects light that actually strikes the retina. Detection through physical contact falls in the category of touch, not sight. Our eyes feel when light strikes them. Light is the information carrier and our brain interprets the information to produce visual perceptions. We do not see the world with our eyes, we see a visual representation of the world, created by our brain. What we see, are the objects from which the light originates."
My opponent claims that it is not the eyes that "see", but the brain. They go as far as to say that "detection through physical contact falls in the category of touch, not sight". What they forget here is that the eye is the one that, as they put it in words, "feels" when light strikes them, and therefore is the one that sends the signals of what it "felt" to the brain, which analyzes the data accordingly. Knowing this, let's examine it with our definition.
"Visible: that can be seen; perceptible to the eye"
Indeed, it is the eye that feels, or rather perceives the contact with the photon, while the brain analyzes it. To make it clearer, anything that is perceived through the eye is called visible. If my opponent disagrees with this premise, they go against every single definition of "visible". Light is perceived through the eye, and therefore is visible. The following experiment proves this thesis:
Lamp experiment
steps:
a. find a lamp
b. connect it to a power source that meets its requirements
c. turn the lamp on
d. observe it carefully
e. close your eyes. (now, you cannot see it!)
f. open your eyes again (you can see it again!)
I hope Con enjoyed the experiment, and realised that my explanations agree with empirical evidence and observation. But still, I am to clarify the remaining misunderstandings under which my opponent is.
1. What we see is different from what we understand after we have actually analyzed what we have seen. What we see is that which we detect through the eye. Hence, we do see the world with our eyes, and then interpret what we see using our brain.
2. "Detection through physical contact falls in the category of touch, not sight."
People have universally agreed that physical detection of light that happens using the eye, due to its special characteristics, is considered sight and not touch.
3. "What we see, are the objects from which the light originates."
Not at all. What reaches and is detected by the eye is light and not the observed object itself. Example of the aforementioned is the distortion of light caused by the effects of relativity when an object of immense mass happens to be between the observer and the observed object. The observer, through the eye, does perceive the distorted image of light but not the actual object they attempted to observe.
4. "Light has no color, isn't made of physical matter and moves at "the speed of light". Any one of these factors would render an object invisible. Air is colourless. We can't see it, but we can feel the wind. We can't see electrons with the naked eye because they are too small, photons have nothing to see. We can't see a bullet flying through the air and light is a million times faster. To actually see light, it would have to give off light, which is impossible as light is a fundamental particle. If light did actually give off light and become visible, we would be blinded by a thick, multicolored fog of light."
a. Light does have colour (even though it is not objective), which is in fact the wavelength of the electromagnetic radiation. If, for example, we detect a low frequency light beam, we will perceive it as red, independently of the colour of the source, as in certain cases, such as the redshift-blueshift effect [2] (Doppler) the wavelength changes due to the movement of the source.
b. The speed of light (300.000klm/sec) does not affect out ability to see light, while Con's analogy was unsuccessful. We cannot detect a bullet with our eyes because it moves in a direction vertical or of a different angle to that which light has in order to reach our eyes. If a bullet was to fly straight to one's eyes, they would see it regardless the speed, though it would hurt a little.
c. Light is just as material as matter is. To be exact, it is subject to a wave-particle duality, meaning it is both a particle and a wave, just like every quantum is. Electrons, protons, positrons, neutrons, muons, all particles behave wavelike because of the uncertainty principle. Even you, the reader, may be subject to the effects of the uncertainty principle, though that's highly improbable because of your high mass.
With the above, I believe I have made clear that light is indeed visible. Thank you.

Sources:
[1] Definitions of "visible", from various authoritative dictionaries
Dictionary.com; http://www.dictionary.com...
Collins Dictionary; https://www.collinsdictionary.com...
The free Dictionary; https://www.thefreedictionary.com...
Merriam-Webster Dictionary; https://www.merriam-webster.com...
Cambridge Dictionary; https://dictionary.cambridge.org...
MacMillan Dictionary; https://www.macmillandictionary.com...
[2] Redshift-blueshift, Wikipedia
https://en.wikipedia.org...
Debate Round No. 2
Furyan5

Con

Pro's entire argument is based on one "fact". That we see the world with our eyes although he slips up and actually admits that we see the world "through" our eyes. I hate to point this out, but what was my one rule for this debate? Dictionary definitions can not be used as priori proof. They are merely opinions and opinions vary depending on who you listen to. I will now prove that visual perception occurs in the brain, through the eyes. The eyes do not see. They merely gather information about the outside world, which our brain interprets. When we dream, we see things. Our eyes are closed. There is no light reaching our retina. How does this happen?

You see, very few people are aware that we do not see actual reality. When our brain receives electrochemical impulses from our eyes, it builds a visual representation of reality. This visual representation is what we see. It's a simulation and our brain is the simulator. I'll admit that in this simulation we perceive light, but this is a sensation. It's light (brightness) we perceive, not light (electromagnetic radiation). The light we perceive is the brains interpretation of the amplitude of an electromagnetic wave. The more energy an object gives off/reflects, the higher the amplitude of the wave. This is interpreted as brightness.

Closing your eyes stops the electromagnetic radiation from reaching our retina. When our cones and rods detect no electromagnetic radiation, they send a particular electrochemical impulse to our brains visual cortex. The brain interprets this electrochemical impulse and creates the sensation of black or darkness. We see black. Closing your eyes doesn't stop us from seeing. It determines what we see.

Completely blind from birth, non light perception, do not see black or darkness. They have no visual perception. This is not easy to comprehend, but it's what you see if you try to look out the back of your head. It's what you perceive when you are unconscious or asleep, but not dreaming. No mental image at all.
So although pro is correct in stating that anything that is perceive THROUGH the eye is visible, we percieve the object from which light originates. We don't perceive light itself. Light itself has no color. Colour is a sensation resulting from our brains interpretation of the lights wavelength. COLORS only exist in the simulation. Brightness is visible, but electromagnetic radiation (Visible light) is invisible.

https://m.youtube.com...

Thanks pro for an interesting debate.
KostasT.1526

Pro

Clarifications:

1. My arguments are indeed based on the fact that we see with our eyes. Seeing through the eyes was intended to be a different way of expressing the same thing, though I cannot understand how me accepting that we see through our eyes favours Con's position at all. If my opponent is more satisfied this way, I state that we see with and through the eyes. Just like the brain, the eyes are a tool of great significance to the process of sight.

2. My opponent claims that definitions of "visible" cannot be used as arguments because they are mere opinions. This is quite a logical fallacy. How can one expect to have a debate on the topic "Is light visible or invisible?" without having a definition of visible? Furthermore, as clarified in the previous round, the definition I cited is the one used and approved worldwide, and therefore is the opinion of the whole English speaking population (with certain exceptions, as apparently is my opponent). Them complaining that they do not approve the definition for this debate without even having given their own definition is unacceptable, and, since a definition is required for this debate, the universally accepted one, which I provided, maintains its validity.
Visible: that can be seen; perceptible to the eye
In other words, I did not use a definition as an argument, according to Con's accusation, but proposed one because it was a fundamental element of this debate and later made proper use of it in order to construct my argument.

3. It is also important to point out that "see" is and will be used as the verb form of "visible" (>vision).

Arguments:

1. If light is not visible, then what do we see? My opponent answers this question by claiming that we see a visual representation of reality produced by the brain. But this is impossible, as, by taking the definition of "visible" into account, if that was true what be perceptible to the eye would be the simulation, which, contradicting the latter, is created in the brain, after the light reaches the eye. The simulation that the brain creates is not what we see, but how we interpret what we see, or rather how we translate the information that our sight gives us.
2. Con also maintains that what we perceive through the eye (see) is the object from which light originates. The absurdity of this statement is evident, while I elaborated on it in round 2 too, receiving no specific answer.

Image 1
Image 2
Image 3
In the above pictures is presented the phenomenon of gravitational lensing, namely, as seen in I1, the change in the direction of the propagation of light because of a massive body that happens to be near it, resulting in the distorion of the observation of the initial object. Of course, we did not want to observe the blue curve in I3, but the source which emitted this light that resulted into being contorted into the observed curve. Meaning, what is visible to us is not the observed object, as Con claims, but the light which came from that object.
Another example would be that of the following thought experiment. Supposing that photons with frequency within the visible spectrum appear out of nowhere and reach our eyes (by out of nowhere, I do not suggest creation of energy, as that would violate the laws of thermodynamics, but energy taking the form of electromagnetic radiation, as happens in the phenomenon of matter annihilation, for example). We would see that light, and depending on the wavelenght, we could perceive it being specifically red, green etc. it is obvious that something is visible here, but it is not an observable object, as my opponent suggests, but the light itself. Hence, light is indeed visible.

Rebuttals:

1. 'You see, very few people are aware that we do not see actual reality. When our brain receives electrochemical impulses from our eyes, it builds a visual representation of reality. This visual representation is what we see. It's a simulation and our brain is the simulator. I'll admit that in this simulation we perceive light, but this is a sensation. It's light (brightness) we perceive, not light (electromagnetic radiation). The light we perceive is the brains interpretation of the amplitude of an electromagnetic wave. The more energy an object gives off/reflects, the higher the amplitude of the wave. This is interpreted as brightness.'
First of all, re-read argument 1, in response to the concept of the "simulation". Concerning whether we do perceive light or not, my opponent even claims that we do perceive light, but we don't perceive light. Apparently, my opponent confuses light for colour, judging from the phrase "The light we perceive is the brain's interpretation of the amplitude of an electromagnetic wave". Thus, we agree that what we interpret as colour is what is in reality the wavelenght of an electromagnetic wave. But perceiving light and perceiving colour are two different things in the first place, the latter being irrelevant to the debate.

2. "Closing your eyes stops the electromagnetic radiation from reaching our retina. When our cones and rods detect no electromagnetic radiation, they send a particular electrochemical impulse to our brains visual cortex. The brain interprets this electrochemical impulse and creates the sensation of black or darkness. We see black. Closing your eyes doesn't stop us from seeing. It determines what we see.
Completely blind from birth, non light perception, do not see black or darkness. They have no visual perception. This is not easy to comprehend, but it's what you see if you try to look out the back of your head. It's what you perceive when you are unconscious or asleep, but not dreaming. No mental image at all."
In brief, closing one's eyes (mostly) prevents the visible electromagnetic radiation from coming in contact with the eye, and therefore, as (making use of the definition) nothing is perceptible to the eye, we see nothing. Black is not something we see, it is the absence of sight. The difference with blind people is that, since they have never perceived anything other than black, they cannot understand that they actually see black.

With all the above, I believe I made clear that light is, in fact visible. Again, thank you for the debate, my opponent, for, despite your interestingly uncommon position, you provided factual arguments, contrary to many people who do so too but it turns out that they are not so bright (!).
On to the voters.


Debate Round No. 3
60 comments have been posted on this debate. Showing 1 through 10 records.
Posted by Furyan5 7 months ago
Furyan5
Light detection, not light perception. There's a big difference between the two. That's the point of this debate.
Posted by Akhenaten 7 months ago
Akhenaten
Light perception is a touch sensation at the sub-atomic level. Light spins at the speed of light and pushes against the nerves in the eye. Thus, electromagnetism is a pushing action.
Posted by Furyan5 7 months ago
Furyan5
Except that direct reality is imperceptible. The radar in the plane sees nothing. Only a pilot can see. And the pilot can only see the radar screen.
Posted by KostasT.1526 7 months ago
KostasT.1526
Please, re-read my previous comment. The case is just the same.
Posted by Furyan5 7 months ago
Furyan5
Now, to differentiate between direct reality and indirect reality lets use an analogy. Imagine a squadron of fighter jets, flying in thick fog. They can't see each other directly or speak to each other directly, but they have radar and radio's. Their radar shows them visual representations of the others planes as dots on a screen. Radio's simulate the voices of the other pilots. So each pilot sees and hears the other planes and pilots, indirectly.
Our equipment with which we detect information are our five sense organs. Our brain can not directly perceive reality except through these 5 senses. And what our consciousness perceived is our brains representation of reality but looks nothing like actual reality. Agree so far?
Posted by KostasT.1526 7 months ago
KostasT.1526
As long as you have the proper definitions, it is correct. Just make sure you mention them in round 1 when instigating a debate ;)
Posted by Furyan5 7 months ago
Furyan5
I can't help it. I assume everything i find easy is easy for everyone else too.

Ok, let's do this slowly, step by step.

Visible: conscious perception of visual stimuli.

Light: electromagnetic radiation (specifically the range detectable by most human eyes)

Our eyes detect certain wavelengths of light. Detecting light is a mechanical process which even an infrared light sensor can do. Perception and detection are two different things. Agree?
Posted by KostasT.1526 7 months ago
KostasT.1526
@Blade0886
Thank you for phrasing it correctly. That was exactly what I was trying to say all this time.
Posted by Blade0886 7 months ago
Blade0886
Furyan back at it again with the Wild thought experiments xD.

No but seriously, it would facilitate people to realise what you are talking about if you went into greater detail and gave your own definitions so that they could see your thought process. I can see endless arguing over definitions that wouldn't have happened if you simply added some in the introductory round.

But you have never been a great pedagogue anyway, So hey :P. We can all improve.
Posted by Furyan5 7 months ago
Furyan5
If you completely understood my point, you'd realize that electromagnetic radiation can not be perceived/seen, only detected. Obviously I see your point. Once upon a time, I thought the same way. 99% of people think the same way. Only a few, highly intelligent people know otherwise.
The book of general ignorance is no tabloid. It's full of facts, verified by experts in the respective fields. It's physics professors who claim light is not visible, while laymen claim it is.
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