The Instigator
Con (against)
0 Points
The Contender
Pro (for)
0 Points

Is "visible light" actually visible?

Do you like this debate?NoYes+1
Add this debate to Google Add this debate to Delicious Add this debate to FaceBook Add this debate to Digg  
Post Voting Period
The voting period for this debate has ended.
after 0 votes the winner is...
It's a Tie!
Voting Style: Open Point System: 7 Point
Started: 11/27/2017 Category: Miscellaneous
Updated: 2 years ago Status: Post Voting Period
Viewed: 3,894 times Debate No: 105330
Debate Rounds (5)
Comments (87)
Votes (0)





Visible light: the portion of the electromagnetic radiation spectrum with detectable wavelengths.

Visible: consciously perceived


Only one. A dictionary definition does not imply factual evidence. Supporting evidence is required.

First round is for acceptance only!


I have read a few of your debates on the subject and I must conclude that your describing the mechanisms of sight as anything other than vision is disingenuous. If we have a sense that detects light and the most common word used to describe this phenomenon is vision then dictionary or not arguments about what these mechanisms can and cannot be called are besides the point. So I was hoping you had either another argument or a better way of phrasing whatever it is that your real question is about
Debate Round No. 1


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.

The book gives no reason or explanation why. This is because the explanation would require a book of it's own. The book would cover physics, neurology and philosophical arguments. Work done by numerous people over the course of centuries. Such a book does not exist, but if it did, this is the condensed version.

I will be using words which some of you are not familiar with. I will put the definition in brackets. Some definitions won't make sense until you're finished, so please re-read the entire answer till it makes sense.

The main reason people believe we see light is because of confusion as to the correct interpretation of words. See, has various meanings, and so does light. People often use the term, "I see what you mean.". This see is not literally seeing, but figuratively speaking. The meaning, to understand an idea. In this sense, one could "see the light.". Likewise, "I see the future.", could be construed as either having a psychic ability to foresee the future, or a visionary, able to predict future events. Then we have the conventional use of the word see, as used in, "I see a ball! ". The latter is the "see" I refer to in my argument.
Light too has various definitions. We have "light and heavy", "light and dark" and light (electromagnetic radiation). The latter is nouminal (exists in the physical world) in nature, while the other two are phenomenal (exists as sensations in our brain) in nature. The distinction between phenomenal light and nouminal light will become apparent during the course of my answer. My argument specifically refers to nouminal light.

Now that you are aware of the definitions of see and light which I'm referring to, let me begin.

Vision has always been a contentious issue amongst the scientific community, since time immemorial. Do we perceive actual reality or representational (images created by our brain) reality. In 1781, Emmanuel Kant put forward the idea that there are two realities. An invisible, objective (existing independently of our perceptions) reality and a subjective (dependant on our perceptions), observable reality. This was the beginning of the philosophy referred to as indirect reality. Indirect reality implies that we do not see actual reality, but our brains representation of reality. The poem by Emily Dickenson only makes sense if you truly understand subjective reality.

The brain is bigger than the sky
For, put them side by side
The one, the other will contain
With ease, and you beside.

What she's trying to say, is that the sky you see above you, is a image created by your brain. You don't see reality outside your head. You see a simulation and your brain is the simulator. This is no longer a philosophy. It's now fact. Confirmed by neuropsychological science. The information from the eye is sent to the brains visual cortex in a digital (piece by piece) format, not as a complete image. As some of you may know, light entering the eye, strikes a cone on the opposite side of the retina, from which the light originates. So light from our left, strikes a cone on the right. Light from above, strikes a cone on the bottom of our retina. This results in an upside down, left to right inverted image on our retina. For many years, people believed this image is what we perceived. That the brain somehow flips the image so we see the world, right side up. Then neurologists made an interesting discovery. Each cone has it's own, individual nerve leading to the visual cortex. Not only that, but a cone on the bottom of the retina is linked to a spot on the top of our visual cortex. A cone on the right of the retina is linked to a spot on the left of the visual cortex. The image isn't flipped by the brain. There is no image in the eye. The image is actually created in the visual cortex, right side up, through a mechanical process. The reality we see is not outside our heads, seen by the eyes. It's a creation of our subconscious which our conscious mind perceives.

I like using the fighter jet analogy.
Imagine, a squadron of fighter jets, flying in thick fog. The pilots can't see each other directly. Neither can they speak to each other directly. They need instruments to do so. Their radar tells them where they are in relation to one another. The information is displayed as dots on a screen. A dot, "represents" another plane. They communicate over radios. It's not the other pilots actual voice but a representation of the other pilots voice. It's important to note here, that the radar detects signals, but only the pilot perceives the dots. Equipment can't perceive anything. Perception is a function of consciousness.

Our brain is enclosed within our skull. It has no access to the outside world except through our 5 senses. These 5 senses are our equipment as we navigate objective reality "the fog". The only difference is, we can't look out the window. We only ever see the radar screen. Luckily our screen is the best on the planet. Better than any television on the planet. The image is so realistic, we think it's real. But it has flaws.

Imagine, if you will, that you're watching a beautiful sunset and it strikes you that light from the sun takes 8 minutes to reach your eyes. This means you're not seeing the actual sunset. The actual sun, set 8 minutes ago. Your beautiful sunset isn't real. There are further delays due to the speed of processing visual perceptions in the brain. What it boils down to is that our representation of reality is delayed. And the further away an object is, the more delayed the image. We see stars which might have gone super nova, millions of years ago. We see things which do not exist. So how real is our reality? To borrow a line from one of my favourite movies, "What is real? If real is what you can see, what you can touch, smell, taste and feel, then real is the interpretation of electrochemical impulses, inside our brain.". To me, reality can not be perceived. It can only be comprehended.

So how does this visual process actually work? How do I see a ball? Scientists will say that we can't see the ball. We never physically make contact with the ball. All our senses rely on physical contact of some nature. Our ears detect vibrations in the air, our tongue and nostrils detect different chemicals and our eyes detect photons. We can't detect photons which don't physically strike our eyes. So we don't see the ball, we see the light. Right? Wrong! When our visual cortex creates visual representations, it creates visual representations of objects, not visual representation of light. Light coming from a ball, causes us to see, a ball. We may not see the actual nouminal ball, but neither do we see nouminal light. We see the phenomenal, representation of the ball. Even when you see a beam of light shining through the clouds, you're not seeing light. It's the dust and other particles in the atmosphere which have become visible. When you shine a torch in someone's eyes, they are seeing the element in the globe, glowing brightly. This is the sensation of brightness. It's phenomenal. Brightness is our brains interpretation of the amount of electromagnetic radiation our eyes are detecting. What you see is light "as in light and dark" and not actual light "electromagnetic radiation". We can not see nouminal phenomena.
I'm running out of space, so I'll rest here and allow you to comprehend everything I've said so far.



My argument is that light is in fact the only thing we see. The mechanisms of vision are only useful because light bounces off an objective. In the same way a bat uses sonar. The bat doesn't hear stationary objects but rather the sound echoing off of a stationary object. You mentioned the sun and how it takes the lights eight minutes to reach us meaning that we are seeing an image from eight minutes in the past because we are seeing the light not the sun. The same goes for objects millions of miles away. Now I'm not going to pretend you don't have a good grasp on the processes involved or that I didn't learn anything, I didn't know for example that the bottom cone connects to the uppermost part of the visual cortex, and I'm grateful but to say that the process of human vision, no matter how it works or why, isn't a process of interpreting visible light, and only visible light I remind you, as a process of detecting the invisible that is disingenuous. Now if you're arguing the brain in a jar "how do we know anything exists at all" hypothesis I'd be happy to, but visible isn't visible like hard isn't hard is a farcical statemen and I really hoped to cover something more substantial than the need to correct the dictionary which seems to be your real goal here. One last thing, for someone who doesn't trust definitions you certainly use a lot of them in your arguments.
Debate Round No. 2


Thanks Pro, that's exactly the argument I was waiting for. Do we see a red balloon, or do we see red light in the shape of a balloon? Most people claim the latter, but there's a problem. LIGHT HAS NO COLOR! Therefore our eyes can't "see" objects or light. People confuse VISION with SIGHT. SIGHT is one of our 5 senses. SIGHT is our ability to see objects. VISION, is the process.

In this round I will explain vision. When I'm done, you will understand why we don't see colors, but rather, colors allow us to see.

Vision starts with an object emitting or reflecting 3 different types of wavelengths of light, at varying intensities. Obviously, objects emit a range of different wavelengths, but only 3 are involved in vision. The rest are irrelevant. What happens in the case of reflected light is that it is struck by the full range of wavelengths, of which, some are absorbed by the object and some are reflected. You could say, that every object in the universe, broadcasts it's own signal. Our eyes are like satellite dishes, detecting these signals. The only difference is, our eyes can detect what direction the signal (light) comes from.

In the back of our eye, is the retina, which has special, light detecting cones and rods. Rods basically detect intensity, while the cone, of which there are 3 different types, detect different wavelengths of light. The way the eye works, causes light from our right, to strike a cone on the left of the retina. Likewise, light from above, strikes a cone on the bottom of our retina. This is how our brain knows where the light comes from. I've already explained how this information is inverted laterally and horizontally to give us an accurate perception of up and down and left and right. This is how we are able to see shapes in the visual cortex. But shapes are imperceptible if they are the same color as there surroundings. An object must contrast from it's surroundings to be visible. This even allows us to see things, which don't physically exist. For example, a hole in your curtain. There is nothing to see because a hole, is the absence of curtain. But the hole contrasts from it's surroundings, so that's why we see it.

When our brain creates visual representations of objects in our visual cortex, it imbues each object with a different visual sensation (color). These colors allow us to see objects, because they contrast with the colors of surrounding objects. This is the primary difference between actual reality and representational reality. Actual reality has no color.


As I have explained, we have 3 different types of cones and then we have the rods, which detect light. The cones detect Long, Medium and Short wavelengths of light and are referred to as L, M and S cones, respectively. Cones are continuously sending electrochemical impulses to the visual cortex. Let's call them N for (no detection) and D for (detecting). When our brain detects N impulses, it creates the visual sensation we call black or darkness. When it detects D impulses, it creates a visual sensation depending on which cone sent the message. So a D impulse from a L cone, results in a red sensation. The rods determine how bright the red sensation appears. When our brain receives D impulses from two cones at the same time, it creates a completely new sensation. So, for example, D impulses from L and M cones results in the perception of yellow or orange, depending on the impulse from the rod (the intensity).

Claiming that visual perception occurs in our brains visual cortex and not in the eyes, is a bold claim. Saying neuropsychology confirms it is far from proving it. Nothing beats direct proof, so, here it is. The phenomena is called pressure phosphene, and as the name suggests, it means seeing by touching the retina. Well the retina is at the back of the eye, so how can we touch it? I'm sure you are all familiar with seeing spots of light when you rub your closed eyes too hard, but I'm going to teach you how to physically stimulate your retina with the tip of your finger.


First, close your eyes, but make sure there is brightness in front of you. Don't close your eyes too tight. You must still be able to perceive some brightness. Now look to your left, with your eyes closed, and gently, with your fingertip, touch the right side of your eye socket. Move your finger up and down and on the left, you will see a black shape moving. The shape will move up, when you move your finger down and move down, when you move your finger up. If you shift your eye to look slightly up, and touch the bottom, left of your socket, you see the dark spot at the top of your vision.

Amazing right! What does this tell us? It tells us that sight is not a result of our eyes detecting light. It's the result of our brain interpreting impulses. It just happens that usually we see because of impulses from our retina. In dreams, our brain creates it's own impulses.

I'll leave you with a question. If you place a person, 2 meters from a basketball hoop and give him a ball, without telling him which direction the hoop is and the person throws the ball through the hoop, we would say he can see. What if the person was blind? Has no eyes. Yet, without mechanical aid or assistance by anyone, he detects the hoop, without touching it and throws the ball through the hoop. I give you, Ben Underwood.

Watch the video and you tell me, can Ben see? Sadly, Ben has passed on, but there are many others who do the same thing.


You have made a lot of amazing points and I have learned things about vision in our conversation that I never would have imagined. I'm grateful for that but I'm not ready to concede just yet. As for poking yourself in the eye, I have observed the phenomenon myself, sometimes painfully. The ability of your eyes to detect a pressure that is not light and your brain interpreting that pressure as darkness is amazing but since it is a separate phenomena I remain unconvinced that this disproves the idea that the first step to vision is detection of light.
As for the amazing young gentlemen Ben Underwood (I'm sorry to hear of his passing) I was lucky enough to view this video already thanks to con's generously giving me a preview in our comments section (some of the information he imparts in this side conversation are wondrous and the comments deserve perusal) and I must conclude that he does not see the basket but rather can hear its position through echolocation. Since bats possess both sight and echolocation we must conclude that they are separate processes.
Debate Round No. 3


What is "visible light"?

"Visible light" is a vary narrow band (3 in fact) of wavelengths of electromagnetic radiation which our eyes detect. But what exactly is electromagnetic radiation?

Electromagnetic radiation is "energy in motion". The establishment claims that pure energy can't exist but light comes pretty close. You could say, light is the energy carrier of the universe. It's how energy is transferred from one object to another.

When light strikes an atom, it causes the electrons to jump to a higher state. You can think of states as lanes in a circular race track. The inner lane is called the rest state. The second lane is a higher state. The third lane is even higher, etc. This causes the atom to take up more space, which is why things expand when heated. HEAT IS LIGHT. You see, electrons prefer the lower, or rest state. Who wouldn't? Lane two is longer. So the electron dumps some energy and drops to a lower state. That dumped energy, is light.

The energy needed to jump from lane one to lane two, is a fixed amount, though it varies from substance to substance. We call that amount, a quanta of energy. So it takes a precise quanta of energy to make an electron jump from lane one to lane two, and the electron gives off precisely that quanta of energy when it drops back down to its rest state. That quanta of energy is called light and it goes buzzing off at light speed, till it meets another electron to excite. If a quanta of light hits a molecule that has a higher or lower quanta requirement, the quanta of light either bounces off, or passes straight through the molecule. ELECTRONS PREFERRING THE GROUND STATE IS WHAT ENTROPHY IS ALL ABOUT!

Heat, is just electrons dumping energy in the infrared wavelength. The light travels in little quanta, called photons. But as you can see, the quanta size varies.

The three different types of cones on our retina, each contain a different type of rhodopsin which absorbs a specific quanta of light. Those 3 types of quanta are what we call visible light. But the light itself is not visible. The light, makes the objects emitting the light, visible. Light itself is not even detectable. When light strikes something, the energy is transfered and converted. It's this raised energy level we detect. At this time, the photon no longer exists. SO IT'S NOT LIGHT WE DETECT, BUT THE COLLISION! Everything we know (or think we know) about light, is based on detecting the collision of light with objects. Light can never be detected without destroying it.


My opponent was right all along. We know the universe is expanding at the speed of light because we can measure the red shift of the light emitted by luminous objects as they move away from us. This is caused by the Doppler effect stretching out the wavelengths (slowing them down from our perspective) that means that color is determined by the speed that light is moving (red light is moving slower, again from our perspective). The Heisenberg uncertainty principle states that you can know how fast a subatomic particle, say a photon for example, is moving or where it is but not both, and the more sure about one of these factors you are the less sure you can be about the other. If our eyes are gauging lights relative speed to determine color then they cannot also be measuring its position.
Mind. Blown.
I can only assume from his choice of the four round debate that he has one more argument. I look forward to reading that comment but I do formally concede. Truth doesn't care about your feelings or misconceptions it just keeps being what it is even when you are wrong.
Debate Round No. 4


Firstly I must thank my opponent for not giving up on what must have seemed like a futile and petty debate at times. Until you actually grasp the meat of the argument, it seems like an irrelevant quibble. I hope my opponent now sees the full implication and the benefits which can be derived from this debate.

This round is basically a summation of the facts, as layed out in the previous rounds.

Light (electromagnetic radiation) is detected (not seen) by our eyes. Objects (not the actual objects but visual representations of them) are seen (consciously perceived) as a result. Due to the fact that we see objects, we deduce that there is light (if we are aware of the visual process). We detect (Not see) visible light. We see (consciously perceive) objects and we understand (figuratively see) light.

Visible light is not visible. Visible light makes objects visible.

Thanks everyone for taking the time to read this debate. Click like on top is you think others should read it.


Anyone that actually understands the principles we were discussing (please read the comments) vote con.
Debate Round No. 5
87 comments have been posted on this debate. Showing 1 through 10 records.
Posted by Furyan5 1 year ago
Just found this clip and a had to share it.
Posted by Furyan5 1 year ago
Correct. And don't worry about votes. If I get just one person to have a better understanding of vision, I consider my debate a success. Thanks for your comment.
Posted by DeletedUser 1 year ago
Wow-- one of the more substantive and genuinely persuasive debates on here. It's a pity no decisive vote was achieved. So, as one who vehemently thought the "visible" light spectrum IS visible-- what else could it be?-- let me know if I have this straight:

Photons collide with the retina, and thereby light is *detected, not "seen."* Via the iris, lense, cones, rods, and brain this detected light is processed into a useful image. We see the image created by this complex process but not the light itself. Evolutionarily speaking, the images are much more conducive to survival than being visually inundated with light rays. Is this about right?
Posted by whiteflame 1 year ago
>Reported vote: BryanMullinsNOCHRISTMAS2// Mod action: Removed<

7 points to Con. Reasons for voting decision: Con by default.

[*Reason for removal*] Not an RFD.
Posted by SecularMerlin 2 years ago
Don't give up. If you can only teach one person in one hundred don't give up.
Posted by Furyan5 2 years ago
Lol, well I'm just glad you see the (light). Remember when you asked if I could convert you? I told you that once you did, you'd wonder how you could miss something so obvious! That's the power of preconceptions. They blind you to the facts. It's just a pity that anyone else reading the debate, won't understand it.
Posted by SecularMerlin 2 years ago
I just went back and re-read all our comments and you know what? I'm amazed at how obvious it was the whole time.
Posted by Furyan5 2 years ago
The pleasure was mine, trust me. Watching you put the pieces together was worth the time it took to put a&#314;l that information on paper. You don't let preconceptions hold you back. To me personally, that's the biggest sign of intelligence. You've earned my respect on the intellectual battlefield.

Thank you.
Posted by SecularMerlin 2 years ago
I think you just converted me. At this point claiming that light is visible because of a collision would be as obtuse as claiming a fire was visible because you can see the smoke. I did not expect to be convinced. I concede sir. I was right more than I knew when I said conversations like this are why I joined the site. Learning is always worth the effort.
Posted by Furyan5 2 years ago
But... detecting light isn't vision. It's a part of the visual process. :-)
No votes have been placed for this debate.

By using this site, you agree to our Privacy Policy and our Terms of Use.