For example infrared and ultraviolet wavelengths have many practical uses that proves that they exist in physical reality, even though we cannot even see those

For example infrared and ultraviolet wavelengths have many practical uses that proves that they exist in physical reality, even though we cannot even see those colors. That should be enough evidence for the person who is interested in truth. Sound waves also exist in physical reality and makes a medium vibrate in correspondence to what we hear. But your argument would be that sound does not exist either and is only made up in our mind? Maybe everything is made up in our minds then, and we arrive at the most boring and meaningless philosophical discussions that have ever existed. But regarding my first comment, I've written elsewhere below that it was incorrect. As the spectrum - as perceived by us - can also be presented as a circle or other shapes. > To the extent that radiation stimulates a color response for the human visual system, there most certainly is purple light, it's just not simulated by a single narrow band of radiation. How colors are perceived maybe depends on the perceiver. But not in the way you argue above. It is evident that purple/magenta light does not have any corresponding wave length in the electromagnetic spectrum that we can perceive and that the only way we perceive it is when mixing blue and red light. The conclusion is that these colors are made in our minds. Unless you can provide an example of a wave length that would be seen as purple by anybody? Color is the way our eyes and mind interpret different wavelengths of light. Will you agree with this?