Does your RED look the same as my RED? 

You have single handedly helped me pass my Philosophy of the Mind module. Thank you so much for your channel!

I remember thinking about the possibility of inverted qualia when I was about 11/12 years old, imagining about people seeing other people thoughts. In the end I assumed it was true and irrelevant and went on with my life, never thinking that I had accidentally bumped into a real philosophical doubt

Regarding the warm / cool part of the talk, because this is a psychological experience, those that see red as green would still say that it was a warm colour, because to them, a fire would look green and feel warm. Also there would be some conditioning involved where people would be saying or teaching that their perceived 'green' was a warm colour. (Imagine an art teacher teaching which colours were warm and cool.) Also, purple is only a unique colour because of language and there is no way it can be regarded as a pure colour in colour science. There are 4 primary psychological colours, red, green, yellow and blue. All other colours are considered mixtures. And there are only 3 in additive light which are red, green and blue, which roughly correspond to the L, M, S cones in the retina, with all other colours being mixtures. So I think the purple, yellow/green argument is fallacious.

Everyone could have the same favorite color qualia-wise.

I just discovered your channel. I'm a technician and a bit of a nerd and, while philosophy has always held some fascination for me, it has never really appealed all that much to me. The two presentations by you that I have watched have given the subject new meaning for me. Thank you. Shalom.

This blew my frickin mind wow

Unbelievable! I just stumbled into your channel. I've contemplated this quandary since I was a teenager. I had a color blind friend and we had some really deep conversations over it. I realize that being color blind is not the exact same thing but it was the segway to the inverted qualia idea. I have brought this idea up to so many people and it seemed that I was the only one that ever questioned it. I've absolutely explained my theory almost verbatim using fire engines and tomatoes compared to grass and trees. However, I could never really get anyone to agree with me or to even show much interest so I actually thought that I was the only one that ever explored this possibility, let alone did I know it actually has a name! Inverted qualia. I feel like I just found another human being on what I presumed to be a deserted island. Thank You! By the way, I've just became a subscriber.

You could say the functionalist is describing the function for each individual not every person who ever lived. Had there been 2 identical persons with identical brains in identical situations, there is no reason to think their experiences would be different.

Okay I'm looking this up because I found out I'm color blind. But I thought that meant I can't see colors. No, I swear to you my greens are blues, certain yellows and oranges are pink, I thought my parents taught me wrong. One day i changed my shirt to a shirt I thought was pink. I don't like the color. My fiance during game night said he liked it, I said " I'd like it more if it wasn't pink" everyone stopped and stared at me and was like...thats yellow. Then we later went over flash cards and to me I was like no was these cards have to be wrong...

I am an electronics engineer who spent the last seven years of my life as a color scientist. Working with laser based and LCD color proofing systems. The three types of cones are long, medium, and short wavelength photo pigment sensitive areas. Long is what you refer to as red, medium is green, and short is blue. I can get a colormetric match in a normal humans by stimulating both the long (red) and medium (green) cones. The person will perceive yellow. I can do this with a single wavelength of light (yellow) or I can get the same perception by mixing red and green light from an LCD screen. If I mix blue and red light the person will perceive magenta. There is no single wavelength of light that produce this same perception. Now if the person has the red and green reversed connections it would be able to produce this same perception with a single wave length of light that overlaps blue and green. This is an objective way to detect if these people exist. I am a functionalist. Talk with a color scientist if you want to know more...BTW I am an anomolus trichromat. A person who sees all wave length of light, but sees luminance differences stronger than color differences that "normal" people see. This can be discovered with a series of tests. I found this out when I applied to get a commercial pilots license. I was able to get that license by using the 100 hue Farnsworth test instead of the Ishihara dot test.

There's no way to know if any two people experience color the same way. Maybe the colors we experience are as unique as we are. ..

In college, I was diagnosed with red-green color blindness. I did not know. I could identify reds and greens, but one time I was told I got it wrong. I would have kept my functional state had I not been told. Now I have a practical difference. The difference I experience for red and green would not create a different quality experience. I just believe what I was told. I would not even know if it wasn't for the eye diagnosis and the feedback.

I once had some medication that suppressed my green receptors under strong light conditions. It's not qualia inversion, but it's amazing how quickly you get used to grass being a dull greyish orange!

Wait a minute you are writing on that board in a reverse manner right...?

The fly in this ointment: color blindness. My relative is color blind to red hues, I was surprised when I was told this. The first question I had was, how do you know to stop at a red light, their answer was when the top lights bright I Stop.

Protanopia and Deuteranopia are types of Anopia. Greek: An - meaning un, without. Opia - meaning vision Protanopia. Prot - from proto greek meaning first of a pair. Green looks more red. Deutranopia. Deuter - from deutero latin meaning second of a pair. Red looks more green. Protanope - a protanoptic person with protanopia who has the condition of protanomaly. Deuteranope - a deuteranoptic person with deuteranopia who has the condition of deuteranomaly. (Optal - visionary, about vision. Optic - from French short from Greek opticus, which comes from Greek: opto - visible and ikus - adjective suffix)

I remember seeing a movie back in the day, probably sometime in the 80s, where there was a guy falling in love with a girl who had been blind since birth, and he was trying to explain things he could see to her. She was having trouble with the concept of color. He asked her to come over the next day so he could try to explain color. He put a stone in the freezer overnight. When she arrived the next day, he boiled a pot of water and put another stone in the pot of water. He took the stone from the freezer and placed it in her hand. “This is BLUE,” he said. Then he took the stone from the boiling water and, after letting it cool off just a bit, placed it in her hand and said, “This is RED.” I can’t remember the movie, but it obviously had an impact on me. Anyone know the movie I’m talking about? EDIT: I think the guy may have also had a room temperature stone that he identified as “GREEN.” Not sure about this part, though…

As long as there is a qualifier that is independent from the individual's experience (a.k.a non-subjective), for an experience, it can be very easily told if a person is experiencing inverted qualia or not. For example if you show the person the color red written the wavelength of the color under it, and the same with green and ask them to write down the number of the wavelength of the color that resembles a tomato, you will know if the person is color inverted or not. (If they write down the wavelength of green, they are color inverted) Am I missing something?

A "mixed color" is just a color which hasn't been named. Purple is a mixed color (and is described as such in the video) of blue and read. it's opposite is a mixed yellowish green. A common name for yellowish green is chartreuse. So what if Rita said the color was "pure purple" and Sid said the color was "pure chartreuse"?

I used to pester my mother about this when I was a child. Only I talked about orange, because my toy was orange. I'd tell her that maybe I see orange as green, but you taught me that it's called 'orange', so now we use the same word to signify two different colors! And if so, we'll never even know! In response she kept repeating, as if I was confused: IT'S ORANGE!!!

Great work, glad you are so enthusiastic. You are a great teacher

This video was posted 2 years ago so, I'm probably to late with this comment, but... it seems to me that when white light is passed through a prism a sequential pattern of spectral color emerges, in other words there is an order to the sequence of how light is divided into color bands by frequency, that is independent of experience, for example if we use 6 letters to symbolize the 6 colors of the spectrum R- O - Y - G - B - V to mean red, orange, yellow, green, blue, and violet. Where Red, Yellow and Blue are primary colors, and green, orange, and violet are the secondary colors... we have a very specific repeatable sequence that appears... . If a color inverted person had red and green color inversion, then they may have a normal experience by their own account when moving through life looking at things, but the order they see color in a spectrum would be different than that which everyone else sees. They would look at a prismatic spectrum and see Green Orange Yellow, Red Blue and Violet. While the color inversion may seem normal to them, if you asked them to lay out 6 crayons of corresponding color to the spectrum on the table in the order they perceive a prismatic light spectrum, their order would not correspond to everyone else experience. We could ask them to draw something with crayons, but suppose they drew an apple, apples in nature come in both red and green. While it is true that without the assistance of another person who had normal color vision to make a comparison, a person would have no reference points within their experience to know that they have color inversion, it would only be a verifiable condition through testing against a labeled spectrum that does not change from one experiment to the next. Our perception of experience, measurement, and the language we use to describe those, seem to all be of relative importance. Perception becomes even more interesting when we examine people who have had traumatic brain injury or stroke that results in hemi-neglect ( a condition where only one half of the brain is functioning normally), and only one half of the world is perceived by the individuals with this condition. if asked to dress their self they will only put clothing on half of their body, they brush the teeth on one side of their mouth and leave the side corresponding to the brain injury un-brushed, they shave half their face, and if you show them a picture of a flower or a shape like a square or a circle and ask them to draw it for you on piece of paper, they will only draw one half of the image. When you question them about why they didn't draw the other side of the image, they respond with complete astonishment, and often anger, they think you are crazy... because one half of the world you perceive does not even exist to them, including half of their own body, yet their conscious mind see everything as whole and complete, they can not detect anything missing. The self is not a good tool to use to use to measure the self, especially if the self is damaged in some way. Our inability to see absence in our perception leads to a lot of questions about just how limited our conscious experience really is, even if it is functioning at its optimum potential. Without reference points, or relative experience shared. by another's experience, we could ask does it even matter how we perceive the world. Than we have synesthesia and several other perceptual qualities or anomalies that you can not determine in ordinary interaction with people. So if we take all of that together, it is quite clear that there is very little chance that common experience is truly common. While we all share many similarities, there are really no two people who are really having the same experience even if they are having all of the same sensory input... and it can be argued that even that is unique in every case, because if two people sit together na watch a sunset, they photons striking one person's eyes are not the same photons that are striking the other person's eyes. The best we can hope for is similarity of experience, because even in repeatable experiments that yield the same data, there is an element of uniqueness that provably exists, and though our perception of those differences may fail, they can be measured. If common experience can be described with common language and two people can agree on a definition of some or other experience, it can never be proven that they are truly having the same experience, but by measurement, the opposite is in fact the case, that no two people are having the same experience... statistical approximations are the best we can ever hope for... we are similar enough to build societies and to have relationships and form families... but from the quarks that make up the atomic particles, to the compounds, and cells and tissue we are developed from, to how we see, think and feel... every person is a unique entity.

I find it fascinating that virtually everything I've ever wondered has been deeply studied before. I've never dared to go further than "maybe I see green and this other person sees red, but we both call it green. How can either of us be possibly wrong?" And I stop there. My childhood was kind of funny, in a way. I always got in trouble for being rebellious, as both my mom and my middle school teachers would agree that I always talked back trying to prove them wrong. I did have a few great teachers that would engage and even welcome my questions. I remember second grade, my science teacher said the floor tiles couldn't catch fire. I was like "yes, they can if you pour gasoline on them" and he was like "that's the gasoline burning, not the floor". I thought to myself "oh, that makes sense, this guy knows so much!". I was so happy because he didn't say in an attempt to shut me down or embarrass me. Kudos to Mr Fajardo!

I may be misremembering my philosophy days, but isn't the point supposed to be that there is no test that we could run to figure out if you see the same green I see? But, in your example, we actually could run a test. We could cut out someone's eyes and dissect their red and green cones and see if they have the correct color goop in there. Right?

Unless someone taps a logic analyzer into the optical nerves, this poses absolutely no problem for functionalism...

But the reaction to a fire truck is also learned, so the person with inverted qualia just has an equivalent reaction to what he perceives, as someone with non-inverted qualia to his perception. It's rather strange to first argue, that the person born with inverted qualia would just build all its associations to match just that, effectively "wire" the input so green associates with gras and red with a fire truck, but then argue, that the functional states are fundamentally different, when they're just equivalent with a rather primitve mapping (exchanging red for green). Also functionalism doesn't care which lanes of nerves transport a green signal and which ones transport red, or even if it's nerves at all, it's completely sufficient, that someone who learned what gras looks like in his sensory system, inverted or not, remembers that association e.g. when describing something else as "gras green".

color is completely culturally subjective though. take azzuro and blu in italian. both describe colors that an english speaker would describe as blue, but to any italian they are distinct and pure colors.

I'm astonished of how many people in this comment section don't get the difference between phenomena and qualia. The number of people who say "just show them the colors and let them name them, and you will know who is inverted" leaves me speechless...

This is weird. I am red/green colorblind. I didn't KNOW this until I joined the U.S.Navy at 18 years old. When you join the military, you have to take a physical. I was in line, to take this test. I was about 3 people away from a nurse, showing this book of "bubbles" to the guys in front of me. The guys were looking at the pages and reading out numbers, I thought they were reading the page number or something, because I saw NO NUMBERS. Apparently, this is a "color blindness" test. For 18 years I never knew I was color blind, until I was tested. I guess your point is VERY sound, if I had never been tested, I would of never known. All I can tell you how it affects my life, I find it near impossible to "match" dark brown and black socks, both look the same. Most "dark" colors blend to my eyes and look the same. Red lights for driving look red, green lights look green. But start to mix those colors and I am really lost. Hope that helps someone.. BTW.. There are tests in the Internet for color blindness, if your a male, you should get tested. Just search for Bubble Color Test, then it will seem clear (or unclear).

It is wired how many people thought about this when they were young, I find this interesting.

Damn these videos are enjoyable

Couldn't you have the colors labeled with their wavelength and just point to a color and say what color is this and find out if there was a difference between two people

When I was young, one of my first deep thoughts was to wonder why we do anything that is fun or joyful or loving because the minute it's over, its gone. It is temporary. We have only a memory. I thought about it in high school because I was on a workout program that was geared toward foods I didnt like. But I justified it to myself because the temporary joy I experienced by breaking the diet would be in the past nearly immediately, and it eould impact my life negatively after that. This thought can be a good motivational tool, but it can also be deeply depressing. Why do we do anything? Its all temporary.

I realized this "color paradox" in high school when we learned women had a different amount of rods in their eyes.

I`ve heard that we actually see upside down when we are born but the brain flips the vision after some time, there has been experiment when they have flipped the vision with a eyelens and the brain has flipped it again. So the question is if the brain does the same when it comes the case you mention at the end of the video. Another question is if it is the brain that does it or is the mind/soul? You can also ask if for example the colour red is a intrinsic property to reality. That would suggest that the building blocks of our minds represent a greater reality.

It seems many people have pondered this, not to my surprise. And, this does prove that no qualia is universal or determinable. On the contrary to proving functionalism wrong, it seems that the argument of inverted qualia only reinforces the arbitrary and fickle nature of experience. There is no such thing as 'redness', there is only literal wavelengths of light. What looks red or green to some individual is completely meaningless beyond the accuracy of identifying the frequency of the light reflected by an object. The experience of 'redness' is simply an application of abstraction upon something that is inapplicable. Thank you for attending my Ted Talk

i love when Philosophy teachers tell you just to accept it for now...before we move on...

Simple answer ' we will never know ' .

I also used to think about this as a kid. I remember trying to explain it by asking, if I could see the world through your eyes would the colours I see look different? Alas no philosophers around at that time to provide an explanation 😂

Help. I am color-inverted. I only see GRED and REEN

It's important to point out that color inversion cannot objectively be found if it's not caused by anything about their cones, thus the input data, but how these data are processed.

Talking about not knowing the difference between internal experiences, I'd recommend looking up aphantasia. Those with Aphantasia do not have sensory recall of one or more senses. Some lack visual imagination, others lack multisensory imagery. They only get live sensory input and cannot imagine their loved ones' faces, replay a song in their heads, some even lack internal monologues. For those that discovered they had it in adulthood, they lived their whole lives thinking that "picturing" something, counting sheep, or a song stuck in your head were just turns of phrase or plot devices. The variety of internal lived experiences is under-researched, and mind boggling

1. Purple definitely looks like a "mixed" color to me. Also note that people raised using different languages that use different color palettes see colors the way they are raised to. For example in Gaelic blue and light blue are two different colors with different names and Gaelic speakers don't psychologically think of them as shades of one color the way English speakers do. This implies that the color identification is socially learned. 2. Color is inextricably linked to the wavelength of the light received, which must affect the nerve-receptors in a specific way, so it's probable that * eventually* we will advance neuroscience to the point where the color question can be objectively answered. 3. Speaking of other "qualia", it's interesting to wonder just how much our experience is translated by the brain into something different from the actual perception. It has been shown in experiments that if a person wears glasses that invert all images for a time (not sure if the exact time needed, but multiple days at the minimum) then the brain reorients the images and begins translating them so that the person now sees the inverted images as "normal". And unlike the color question, these are people who have experienced normal vision and can report that what they are seeing is different from what they saw before. This has weird and unexplored implications concerning qualia and the relationship between the brain and the "self" (or the part of the brain that we think of as the self and other parts of the brain).

Maaaaaan, I remember having this conversation when I was like 7 years old. I thought everybody had this conversation.

I might be very confused here but might there be a way to figure out if your color inverted? The colors red and green are at different wave lengthsnofbthe light spectrum, which means they have different properties and can be measured. I *think* thats part of the reason why plants (because chlorophyll) here on earth with our particular sun and atmosphere are green. If someone is color inverted could they see that their measurements dont make quite as much sense as otherwise. Cant word this properly on my phone :/

I think the functionalism response would be to re-imagine their idea of mental state = functional state would not mean that the mental states were exactly equivalent between individuals but the concept of differentials would be equivalent . That is to say that the mental state is not a definitive quantity or quality, but rather is merely a contrasting perception of differentiation .

As the child of two optometrists who has far too much useless information about eyes, I'd like to point out that most red-green color blind people don't have a complete swapping of "the goop." The majority of folks with Protan-type and Deutan-type color blindness (so an error with the green or red cones) really have a *shifted* goop-setting rather than a fully swapped one. So their red cones pick up wavelengths that are closer to green than should be, or vice versa, making it harder to differentiate colors, but not impossible. IE: Bright red and bright green still look different, but less saturated colors just start to look brown or grey. Someone who has the same goop in both cones literally won't be able to tell the difference at all, so even the red and green of a stoplight would look exactly the same. Point being, "color vision glasses" like Enchroma only work on people with shifted-goop color blindness. Those glasses actually work by filtering out certain wavelengths of light between red and green, allowing the brain to differentiate between the two "channels" more than it normally could. So when wearing the glasses, green light only activates the green cones and red light only activates the red cones, rather than both being activated to some degree at the same time. What's SUPER COOL about that to me, is that under the paradigm he lays out in this video, where the activation of the "channels" = the qualia, Enchroma glasses actually literally allow people to see red when they couldn't before! If red goop in the green cone and green goop in the red cone would cause experience/qualia inversion, then the differentiation of your red and green channels IS THE SAME THING as true RGB color vision! TL:DR: Enchroma glasses do actually let you see red/green!! For really reals!!! (Not sponsored or anything I'm just a nerd)

on the note of the example with the person seeing everything twice as big as everyone else. well, if you ever used a VR headset this might actually sound familiar. in VR, if the game's camera settings and your VR headset's lens/eye distance isn't calibrated correctly, everything will look either super small or super big to you. because you are used to how far apart your own eye are. you are used to how the scale of the world around you is, based on the position of your eyes. move your eyes closer together and everything will look larger to you, move them farther apart and the world around you will look too small. I bet you could achieve the same effect by using mirrors arranged in a certain way in a glasses like thing you put on. so in a way, we indeed kinda see a different scale, but because we are used to it since it's the only way we ever saw the world, everything looks normally scaled to us. change the position of the eyes tho and everything will look off.

The argument around 15:00 about 'pure' and 'mixed' colors presumes that these are a universally percieved. I doubt the validity of that argument. Being a phonetician, just playing around, I once asked some Dutch and Hungarians which of two sounds sounded more complex to them. These sounds would be represented in English by 1./s/ and 2./sh/, in Dutch by 1./s/ and 2/sj/, and in Hungarian by 1./sz/ and 2./s/ respectively. All of the Dutch judged sound 2. to be the more complex, but all of the Hungarians chose sound 1. Clearly, a seemlingly objective quality like simple/complex may be influenced by the complexity of the writing or labeling that is associated with it culturally. Similarly, using separate names for certain colors, could contribute to perceiving those colors as more 'pure'.

Imagine living in a bright red forest. Now that would really stress me out. Red is a color used for warning in nature for a reason.

I thought about this very thing when I was growing up because my left eye saw red less saturated or more subdued than my right. I have heterochromia or whatever its called and I wondered if having different eye colors might affect what peoples favorite colors were because of how they perceived colors.

Great content! Can you do an in depth video on Dworkin's constructive theory next?

Isn't it true that, at a more basic level, when two people see green, different sets of neurons fire in their brains . But language teaches them both to call that experience green.

There is book called "Fribble." It is about kid who wants to call an ink pen a Fribble. This book is exactly what you are talking about. It is amazing what we "Title" things is in line with majority convention.

Wouldn't you know if you were inverted if everyone told you the red stop light was on top of the traffic light and the green go light was on the bottom?

I would utilize a dark hue of orange, purple and green and asked which one stands out to them more. The color that is Orange being warmer and brighter in it's very essence, should stand out more compared to colors closer to colder hues like purple and green, even if in it's tinted. I would ask him which color appears brighter in pigment in comparison and that' s how we would know we see the same thing.

I know it's not the main topic here, but there is a way in knowing if someone has color inverted sight. I'm an electronics technician, resistors and wiring in some systems are color-coded, each color correspond to a number, converting those colors to numbers gives you their resistance in ohms, if I saw inverted colors, I'd mistake the resistance value of every resistor that has that color in them, thus realizing I have a problem seeing some colors correctly.

I think qualia are like variables used in programming - it doesn’t matter as long as they stay consistent for the individual. Everyone’s are probably entirely different, so “switching” makes no sense.

when we were in college we talked about this idea without knowing it had a published philosophy paper, we are talked about make a movie like this that would be fun,

This is only consistent when we are talking about opposite colors on the color wheel, the rest is collor blindnes. Then if every color were swapped (including black and white), in theory, people who see white as black should be tired because black makes you want to sleep and white makes you wake up. Assuming that the brain reacts only this way to given visible light wavelength. ---- if only two colors are changed or shifed (where there is a second such combination to be balanced), and is not black and white, we will never know if someone has a different vision than we do.

My way of somewhat? being able to tell that I'm not red green colour inverted is that I like the same color schemes that most people like.

It’s highly likely we all perceive color the same way (except for colorblind people or some genetics issue) because the according wavelengths of colors stimulate the same receptors in the human eye. Everything else is just definitions we agree on, like different languages.

I feel like there are some limited tests we can perform. One would be optical illusions, for example how people's brains think red + blue = violet. Violet is its own separate color past indigo, and yet people's brains see red + blue as real similar to violet. That optical illusion seems to be rooted in funky brain wiring, so if people share that illusion, they've got similar wiring. That doesn't prove IDENTICAL wiring, of course. Another possibility is the ability to recognize color similarities. If everyone sees red and orange as more similar than red and blue, and green as more similar to blue than yellow is to purple, then perhaps people are seeing colors the same. Still another possibility is linguistic, but I'm not sure this is germane. There is a pattern among languages, with how many color words they have. Languages that have the most limited set of color words, always have black vs white. Languages with just one more color have a word for red. And so on, with pretty much the same "order" of words emerging in a language. That suggests a need to express concepts that are commonly perceived, maybe. Black is dark; white is bright; red is vibrant.

The problem with this whole argument is that you're assigning a particular nerve to a particular colour. Why is that assumption valid? If the nerve makes its way into the brain and stimulates neurons then its doing its job and the brain has neurons stimulated that it further interprets through subsequent neuron firings and so on. It could/should make no difference whether the signal came through one nerve or another when it enters the brain if the brain has learned "red" then its learned it through stimulation of the "red" nerve.

Surely observing colours (and in particular there placements in relations to other colours) on a colour wheel or the order of them in a rainbow would help identify people who saw things differently? Also, technically the colour of any object is the opposite of what we perceive. For example a red object only appears red to the observer as that is the frequency of light that bounces off of that object. The object is actually absorbing all the other colours of the spectrum. So, you could argue that any object is all of the other colours other than the colour we observe them to be.

What is the color of peanut butter? My first roommate in college was green-brown color blind. He could not distinguish the colors of green from brown. I told him, "Then, Don, you do not see the same color for grass that I do." He got angry and said "of course I do." Then I asked him what is the color of peanut butter. He said green. And I informed him of the contrary.

I know a guy who had synestia but he didn't know this until he got home from work to find his wife worried about the kids, because the kids had been talking about the colors of the days of the week. He responded with "So what. The days of the week are suppose to be colored.

You: "How do you know that you don't experience red the way others experience green? Me: I'm colorblind, and I know for a fact that I perceive way too much green light, so, yeah, I do see red like most people see green. But seriously, as someone that really does see colors drastically differently, I can vouch for the fact that the mixed/pure color rebuttal is rubbish. Even though I see red as a mixed color (red and green) I perceive it as a pure color, because I was taught my red is a pure color. My red still looks warm, because the warm things are my red. I remember learning I was colorblind. I'd been alive for over a decade, passed kindergarten with flying colors, identifying all my colors well enough to not raise any suspicions, grown up enough to be able to have favorite colors and talk about colors and what they represent and how they feel and more. Then I was playing with a red bow and arrow toy. I shot a red arrow into a green bush and couldn't find it when I was looking nearly right at it. I didn't believe that everyone else could see it easily, and thought everyone was pulling a prank. It took months before I was really convinced I was colorblind. It was weird, and baffling, and disorienting, but I'm a teacher now, and I really enjoy teaching my students about how I experience qualia differently, and use this thought experiment to help my students grasp the concept. Glad to see someone else thought of it as well.

I think it is simpler than described in this lecture. Irrespective of the “gloop” in the eyeball, there is no way of knowing whether the sensation I experience as a colour is the same as the sensation someone else experiences as a colour. We call the experiences we both have as red or green or blue or whatever, but there is no knowing whether we have the same experience. Maybe that is one of the reasons why some people think that certain colours “go together“ and other people think they do not.

The answer Kaplan is - Occam’s Razor! Constant reaffirmation and education would lead that person to know what they have been see was red was actually green. And vice versa. They would live with this idea and adapt.

This qualia inversion is a fact amongst many people. Let me give you an example. In the English language we announce the number like 45, by saying forty five we announce the tenth digit before the units digit. In another language the number are announced differently ie, the first digit is announced first followed by the 10th digital. This means that unless, there is a switch these two processing system would not be able to properly communicate.

One caveat here, the way we perceive the electromagnetic spectrum needs to be consistent. Blue could be described as greenish, and orange is not far from red. Our brains assign color qualia that makes the electromagnetic spectrum consistent. Blue and Yellow still have to make green. Red and Yellow still have to make purple. Yellow would be inconsistent if it mixed with blue to make red, but also mixed with green to make purple.

A Functionalist might point out that there is a confusion going on, a misunderstanding of functionalism and between what is a brain state and mental state. One of the arguments for functionalism vs mind brain identity theory is that different brain states can (possibly) give rise to the same mental state. The possibility that creatures with completely different brain systems might still experience pain or other mental states. Mental sates are thus not uniquely realized, but are (can be) multiply realized in many different ways. Therefore, brain state=/=mental state. The whole inverted Qualia/Senses argument is for the functionalist not different mental states, but simply different brain sates leading to the same experience. If the idea is true that such a person would "experience" the switched Qualia/Senses by also switching the assorted experiences, for example with color also switching the experience "hot"/"cold" or "warm", then this would actually be a strong argument for this view. Functionally, the mental states of inverted senses are (completely) the same, so by definition of functionalism they are the same mental states. For the functionalist, they are just running on different brain states.

I was also thinking the sensation I feel for pain could be someone's experience of pleasure and I will never know since their responses to stimuli is consistent to mine.

What would purple look like? I wonder if there is a way. Yet again I’m too early was already half way through saying no a kid wouldn’t have that experience

How we perceive color is done in the brain, and because of that, we have absolutely no way of knowing how any person perceives "red" or any other color. Color is just a word that defines a "mental confirmation" that our brain creates when it demodulates the visual signals that it receives via the optic nerves. We can safely assume that my "red" is the same, or at least very similar, to the "red" that most or all other humans perceive in their brains because of the fact that we are all humans. The same cannot be assumed between humans and animals. In my opinion, we can not, and probably never will, be able to determine exactly what a person perceives as "red" or "green". Anyhow, "WHO CARES?"! If my brain sees what you would say is a green fire truck, and your brain sees what I would say is a blue fire truck, it really doesn't matter because we will both call it a red fire truck!

Darn! I had this same thought experiment at age of ten and everybody looked at me exposing it as if I had go nuts... so I learned that you are BORN NERD, not learned.

2 people looking at the color red. What do they see? Mix it with yellow, without letting them see. Ask them what color they see. Do that with every combo.you will find out how different people see colors.

Whenever grass starts looking red to me, I know I have to cut down on it a bit

It is now the second video of you that I watch and I experience a deja vu. I read William Poundstone's Labyrinths of Reason 30 years ago...

Color temperature is more complicated than you suggest, it's not just that reds are warm and blues are cool; there are warm tone blues and cool tones reds but colors that are thought of as warm have a wider range of warm tones and vis versa for cool colors.

Can’t you just test this with a hex color wheel and ask people to write down objects according to the color they see which would have a hex code attached to it which we know what it looks like to “mostly everyone else”?

Temperature is related to color, higher wavelength light is warmer. Use a prism and split the light and put a thermometer in each color, theyvwill read different temperatures

If you use a paint program to make a pure red shape (RGB = 255,0,0) and a pure green shape (RGB = 0,255,0), then adjust the image to Black & White, then you will end up with two distinct colors of gray - a darker gray (RGB = 76,76,76) for red, and a lighter gray (RGB = 150,150,150) for green. So as long as the grayscale shading aligns when we both look at the color red, then we can agree that the colors we're seeing are the same. Right?

It doesn't matter. What matters is the frequency of the light detected. Two people looking at the same bird from opposite ends would be seeing different things, but it doesn't mean they aren't perceiving the same bird

This would all be so much simpler if we all just started saying "wow, isn't the sky a lovely shade of 470 nanometers today?"

3:40 The person, growing up with a "flipped" green-red sensor, would not even realize it. They see all the things everyone sees as red, they are called red, and red mixed with yellow makes orange, it all _works_; he would not even be able to tell that his sensory input was different. The child would never even KNOW that the fire truck was "green"; it was the color everyone calls "red."

Pink is red. It's linguistically weird that we treat it as a separate color, rather than just a shade of red, as we do with other colors. So that's fun.

Black body radiation is an independent measure. Diffracted light places colours in a particular order. It should be easy to discover if your perception of colours was inverted.

I thought of this in 5th grade and explained it to my friends on the playground. Later in college when I studied perception and psychobiology, I learned about cones and rods and the evolution of the eye, which tells us that we process the light spectrum the same way.. yes, there’s color blindness, but that’s different and mostly about how we parse blends or mixes of colors

Whatever colour I perceive , I must damn admit that I find them to be perfect 😂

What happens when one orders red paint, brings it home and paints his door and it looks green?

While it is obvious to anyone who thinks about it that our entire existence is a mental construct, it is not true to then say that therefore we have no way of knowing if our internal experience of the external world is the same as or different to anyone else's. We can strongly infer that we have the same experience, aside from genetic or other abnormalities, because we share a common ancestor.

It may be that no two people have the same color experience. Different people have different favorite colors, But everyone actually has the same color. If what I call green (my favorite color) is what you call yellow (your favorite color).

When one of these color-flipped men mixes red paint (which they see as green) with blue paint, they won't see purple, like the rest of us, correct? They'll see some muddy-looking mixture of blue and green. Why can we not detect this?

Even if we are not color inverted, our perception of colors, e.g. red, changes over time as we get older... we notice this only when we start wearing glasses. red becomes redder... But we never question if what we are seeing as red is really red, although the reds we saw in years are different forms of red (sharper, duller) .... And, we do not notice it... What I am really after is, is there any discussion connecting this argument to reality arguments, reality as being socially constructed etc. If anyone came across any readings please put it in the comments.

I am absolutely serious. Mr. Caplan, this is the 4th video that am I watching. Videos from you. Everytime it felt like as if you were talking about something, that I already was thinking about and asking myself about, intensely, but I never spoke to anyone about these thoughts. Are you reading my mind or what is going on here? /// edit: It feels like a dejavue, or being inside the trueman show, or a glitch...

This talk was before chatGPT obviously. And large language models erase Searle critique of functionalism

I've always asked myself this question,I just want to see life in someone else's eyes

This is an effective way to explain what Wittgenstein was trying to say. We have language because it's useful to us.