Philosophy- What Do we See?

What do we see with our own eyes?
An Example: I could say that the colour I see is Blue. However, it is just a noun for this colour. To someone else the blue I see could be completley different. To them it could be my version of Green.

But we can never know as Colour is unexplainable.

But color as such is utterly explainable.

The more general question is if one is able to know what color has an object (call this Objective Reality) if one don't know color of the glass (call this Observer) through which it sees the object.

You first have to find out the color of the glass

As any physics textbook will tell you, color is rigorously explainable in terms of electromagnetic waves. Moreover, the way our eyes perceive color is just as rigorously explainable in terms of a specific photoreaction (trans-cis-isomerization) that happens in specific molecules (Rhodopsin) in your retina.

zt09 wrote:

The more general question is if one is able to know what color has an object (call this Objective Reality) if one don't know color of the glass (call this Observer) through which it sees the object.

No you don't. You first have to find out the color of the glass by producing light of a known wavelength, shining it through the glass, and deducing the color of the glass from the percentage of the the light that the glass absorbs. Once you know the glass's absorption spectrum, you can reconstruct the object's absorprion spectrum, and hence its color.

The only reason that physicists know that a certain light wavelength corresponds with a certain color is because they can already see the colors

But that doesn't establish that everyone sees the same color blue.

Of course, if by "seeing" you mean a form of perception that happens on a neurological level further up in your brain's signal-processing stack, all bets are off. But then I don't see anything that could establish whether my blue is your blue or not. The question, "is the `blue' I see the same as the `blue' you see?", simply becomes unintelligible under this definition of the term "see".

In real world yes. But what if WE ARE the (thinking) colored glass (of course I understand this is even more absurd example but still...). The only way to find out our own color is to ask another thinking (and speaking) glass what color we are. But what if another glass has another color? Yes, we can see this color but ... through our own glass. And so on... And so on...

joefromchicago wrote:

The only reason that physicists know that a certain light wavelength corresponds with a certain color is because they can already see the colors

That's not true.

Here's another reason physicists know that: Together with biochemists, they have examined the photoreceptors in our eyes and measured which of those photoreceptors respond to which wavelength of light. (In different photoreceptors, different electrostatic environments surround the retinal molecules, shifting those molecules' absorption maximum in a distinct and predictable way.) In principle, then, even a team of color-blind physicists could have figured out that most other humans can see colors, how many different colors they can distinguish, and which range of wavelength each color corresponds to. The physicists themselves didn't have to see colors to figure out the correspondence.

That depends on what it means for you to "see" a color. If the sentence "I see blue" means, "incoming signal to my visual cortex from my retina's type-blue photoreceptors", then you're wrong: The biophysics of color and its reception by the eye do tell us that my blue is the same as your blue.

Of course, if by "seeing" you mean a form of perception that happens on a neurological level further up in your brain's signal-processing stack, all bets are off. But then I don't see anything that could establish whether my blue is your blue or not.