Hobbes Choice wrote:DavidMcC wrote:Hobbes Choice wrote:DavidMcC wrote:You only experience red when you see a bus when the physical colour of the bus is red, barring non-neutral lighting conditions, of course (eg, a silver bus with a red light shining on it).
Science makes a mockery of your naive realism.
Colour is a quale of experience. What you are experiencing subjectively, is differences in the wavelength of light in objective terms.
Yes, sure, which is exactly why the experience of red when you see a London bus is down to the paint on it and not just people's imaginations.
This is obvious enough since we can demonstrate that humans have at least three different modes of colour perception due to genetic differences; and the colour perceptions of animals varies also from human colour perceptions.
That is misleading, because the genetic variants on the LW and MW opsin genes differ in peak wavelength by only about 5nm, so the red is still red and the green still green. And of course different species have different kinds of cone receptors (if any) with different kinds of cone opsins, so they see colour differently from us (if at all).That is well known, and has nothing to do with this discussion.
Perhaps you though my reference to physical colour meant that I thought that we directly sense colour, or something daft like that. Or, more likely, you are trying to paint me in stupid colours.
PS, like most scientists, I'm an indirect realist, not a naive direct realist.
A bus painted "red" appears so because the light it reflects has a different wavelength.
Different from what? Physical red is 600-800nm wavelength.
When we perceive redness that is something wholly different. We can never even tell if one person's experience of red is anything like another's, we can only assume that. In fact given what is laughingly called "colour blindness" we can be sure that our experiences are different.
What's laughable about having fewer cone cell types than normal, or a damaged optic nerve, or other problem?
The internationally celebrated dress that appears to some gold and blue, and to others black and blue, should be enough for you to understand that not only can we not be sure out experience is the same as others but that the human brain is in a constant state of interpretation and reinterpretation of the colour balance.
Ha! As someone pointed out at the time, that was just a heavily over-exposed photograph by an incompetent press photographer, making the blue look white and the black gold.
The brain filters out the colour shifts from warm artificial light to the cold blue day light, as any photographer can tell you; and the consequence of this is that we miss the true nature of the redness of the sunset, by subjectively and unintentionally changing our internal hue setting.
I know that, it's called colour optical illusions, but it isn't anyhting like sufficient to make a black & blue dress seem gold & white!
No one is saying that paint does not exist, and that it has different light reflecting properties; but that the quality of each colour is about cerebral experience and not an objective quality of reality.
The Mononchrome Mary thought experiment of this issue is very instructive.
The problem with Mary's room is that it is unscientific, becase no mother would allow her baby to be brought up in a totally b/w environment for years. Therefore, you can impose whatever "result" you want on it, and no-one can contradict it with evidence to the contrary.