koti

@Lasse, could it be that you are confusing faith with trust? From what you wrote so far it is pretty apparent that you have certain scientific knowledge and that you believe that science, based on its previous success will bring results in the future. This line of thought is trust in results - not belief or faith. The use of the the word „believe” in my previous sentence is equivalent with trust in this context. Considering that your English is somewhat lacking, could it be that this whole disagreement is semantical?

Not at all. This just means, like strange already explained that there is no universal now, now is relative and its a measured property of time, not something to do with perception. Time runs differently for different observers, this doesn’t mean that time doesn’t pass for some observers or it stops. Not really...it depends how you define „observation” If by observation you mean perception then no. If by observation you mean applying electromagnetic radiation onto a subject (turning your lamp on to see whats is the room) then yes.

No its not.

This is where color management comes into play, there can be various components and technologies involved. The consumer market commonly uses sRGB or Adobe RGB in your camera into an ICC Profile on your PC/Mac OS into a CMYK ICC profile in your printer OS where all are bound by CIE LaB which is used as a color "reference language" CIE LaB is an independent color model unlike RGB or CMYK which differ between devices. Color management in professional use is almost always done by custom calibration using colorimetry calibration devices which combined with software and hardware provide calibration to all devices involved. There are custom color models used by various companies, for example Hasselblad professional still cameras have their own color workflows. Film production color management is a whole different ballgame involving customized technologies. So the answer to your question is that colours are unfortunately as scientifically correct as you make them. Thanks Bender and others. I think I'm at what I started off with before this thread.

I got 2 downvotes for asking for evidence on a science forum in the physics section. I wonder who the other „scientist” is. This thread shouldn't even be in the physics section as it deals with color perception which has nothing or very little to do with physics.

@Mehmet Saygın, I got more than 10 downvotes from you in various threads in a timespan of a few minutes and you insulted me for no reason - please stop doing that. Behave. Edit: And the downvotes keep coming, this time presumably from a different account. I think 16 is the final count as of now.

So much for a civil discussion. Good luck with explaining your false premises to others.

Again, this time its in the title itself of what you linked: ”Is the sky really blue? Some hunter-gatherers don’t describe colors the same way most people do” I’m glad you took a deep breath, it will be easier for you to understand that your statement: is wrong. Color perception has to include the brain. The physics processes involved are the same for everybody but color perception happens in the brain.

No. Actually that popscience article states exactly the opposite of your claims that we all perceive the same colors. Try again.

Any evidence for your claim ?

There is a lot of research on this but it might be a difficult subject to fully grasp - color is only in your mind. It’s a sensation, just like touch is. Color doesn’t have any physical reality of it’s own, at least not outside your head. This might sound strange but its confirmed by research - Color is not a property of the thing that’s causing the sensation. So in fact grass is not green and the sky is not blue, rather they have physical properties that make you perceive green and blue, but even that’s true only sometimes.

You are mistaken. Two healthy individuals will perceive color differently based on many factors including previous experiences, psychological factors, etc. Color perception is subjective and its not a myth, its a well known fact, we all see color differently. http://www.statlab.uni-heidelberg.de/projects/colour/colour.pdf

1. Double slit experiment. Get your hands on a laser pointer and build the experiment. 2. Use a high fps camera, come up with some interesting experiment for ex film various display screens to show how they actually display an image (okd CRT, new OLED) you can combine that with a showing the construction of the various displays under a microscope. 3. GPS, how it works, whats needed for it to work, explain why relativity needs to be taken into account when bulding satelites and GPS systems. 4. Something involving LiOn batteries...you can build a small battery pack cspable of starting up a car engine. Show the energy density of the new technology LiOns, involve info about Tesla and Musks Giga Factory.

At least two other members expressed interest in you explaining this further, including a resident expert. I for one am far from being an expert on this subject so I’m curious what the usefulness of racial categorizing you talk about would be. Please explain.

In order to determine anything about color you need a reference point. These refefence points are color models. So a certain color will have more lightness than another color only if you operate within a color model framework. If you do not use a color model it is impossible to determine anything about color besides subjective statements based onhuman perception which is different for everyone. So your statement that „yellow is the second lightest color” (what does that even mean) doesnt make sense without opersting within some color model. Your question how to explain that physically is null as a result. You need to be more specific, try rephrasing what your question is.

550nm is perceived as a more vivid color because its right in the middle of the visible spectrum. Im not sure I understand your question but regardless of the color model used, that is the case. Obviously you will get differences in vividness of color depending on the technology used but when its around those 530nm-550nm green you’ll get apperance of higher brightness compared to other wavelenghts. If you have two identical power lasers one 530nm and the other some other color like blue or red, the green one will appear brighter to the eye (it actually isn’t brighter though) You get very different results of color perception in the subtractive color model...in theory a green paint on a car should appear brighter than blue paint but it depends on factors one of which is the most important - color perception is personal, we all see colors a little differently. Regardless of the color models or technologies used, the colors from the edges of the spectrum (blue on one side and red on the other) will be perceived as less vivid/bright than the colors more to the middle of the spectrum.

You’re conducting a monologue without any will to learn or understand what is being layed out in front of you. Phi for All and others gave you sincere, well phrased and exhaustive answers and comments to which you are blind. This comes as no surprise to me, in fact it is very typical of people of faith. Go on, have some more.

I can see you’re knowledgeable on the subject, wanted to hear your opinion, lets hear it.

Could you give examples of the usefulness of racial categorizing?

I was trying to explain Strings statement, it's not what I think, here's what I think; Obviously there are biological differences between people, there's too much variation for there to be none. Whether they are major or not depends how you define major. You being prone to that condition you mentioned is a major difference? I don't think so....your reproductive organs are where mine are and there's ears on your head, that's good enough for me to conclude there is no major biological differences between us. But that's not even the case here, whether it's skin color or height or hair color or whatever other feature or difference, humans tend to be prejudiced. Some less some more but its there almost always. Race seems to be a social construct in certain frameworks of thinking, I'm sure its possible to devise a framework in which race will not be a social construct. It all comes down to civility and accepting or not accepting differences between various things. I had a student in my training in South Africa a few years ago, he had the darkest skin I've ever seen on a human. His black colleagues were making fun of him, after the training one of them started to turn off the lights to see if we can see him, etc. Apparently he was back from a 2 week holliday where he got a tan and his skin turned literally black, I talked to him over a beer after the training. His black colleagues who commented the loudest on his tan were the most reluctant to grab a beer with me after the training (I'm as white as they come) I've seen this same mechanism happen all over the world with various people, it seems that some are curious and more tolerant towards various differences and some ar not. Oh well.

I was convinced that causality is always preserved even at the quantum level at or below planckian durations hence my conviction that if causality is preseved, change is inevitably happening. Or am I completely wrong?

Okay, this is beyond my knowledge, I have no idea. I think I do understand what you mean when saying that electrons aren’t orbiting the nucleus (quantum mechanical fuzzyness happening) but does that imply lack of any change at all?

As long as time is progressing and we can measure the duration, there is change happening. Electrons are orbitong the nucleus, aunt Irma is cooking dinner, etc.

You’re right, I should have quoted the whole thing, its a powrful statement. I just took a couple of minutes to think about what you said that duration doesn’t necessitate change and I don’t get it. Rate of change and duration are just means of measuring, they both imply change which is inevitable whenever time isn’t at stop which as far as I know doesn’t happen. So if there’s duration there has to be intrinsic change? Or is my brain so tired after a whole night of poker that Im missing something?