As Wittgenstein wrote in PI 244, pain is different to pain-behaviour
How should "colour" be defined
The Merriam Webster dictionary defines colour as a phenomenon of light (such as red, brown, pink, or grey) or visual perception that enables one to differentiate otherwise identical objects. However this is ambiguous, and does not address the problem as to exactly how does colour enable one to distinguish between otherwise identical objects.
It depends how you are defining the word colour. If you are defining colour as a name, such as "green", as names have been created in the human mind, names cannot exist independently of any human. But if you are defining colour as a wavelength, such that the colour green is the wavelength 495 to 570nm, then in this sense colours can exist independently of any human.
As defining colour as a wavelength introduces the confusion of over-determination, whereby two very different concepts are given the same name, the definition of colour should be limited to that of a name. In this case, colours can only exist in the mind.
1. Scientists are not naming the color green "550 nm — Richard B
I agree that the colour green has not been named 550nm, but rather the wavelength of 550nm has been named green.
A group of humans look at several objects and come to a communal agreement that there is a certain similarity in the objects emitting wavelength of 495 to 570nm, there is a certain similarity in the objects emitting wavelength of 570 to 590nm, and the objects emitting wavelengths of 495 to 570nm are somehow different to the objects emitting wavelengths of 570 to 590nm. In the English speaking world it is agreed that the objects emitting wavelengths of 495 to 570nm are named "green" and the objects emitting wavelengths of 570 to 590nm are named "yellow". In France, they would be named "verte" and "jaune".
2. We need the device to detect the color of an object that is independent of a human but will detect and report the color as humans do. — Richard B
The device detects the wavelength emitted from an object that is independent of a human, but no device can detect the colour of an object independent of a human.
The community has agreed that objects emitting wavelengths of 495 to 570nm are named "green" and objects emitting wavelengths of 570 to 590nm are named "yellow". These humans can then make a device that distinguishes the wavelengths emitted by different objects. The human designer of the device then programs into the device that if the device records a wavelength of 495 to 570nm, then the device gives the output "green".
3. I am not sending a color that exists in my mind in the mail. — Richard B
I agree, you are sending a physical object through the mail that emits a particular wavelength, not a colour that exists in your mind.
4. The human brain is like the device that detects color. — Richard B
The human brain is different to a device. The human brain directly perceives colour and only indirectly knows about wavelength. The device directly detects a wavelength but only indirectly gives this wavelength the name of a colour.
I agree that the human brain has evolved to sense and discriminate different colours. However, if it weren't for science the human would be unaware that they only perceive colour because information has travelled from the object to the eye in the form of a wavelength. Humans know colour directly, and only know about wavelength indirectly.
On the other hand, a human-made device is only able to discriminate between different wavelengths. These wavelengths can then be named by a human programmer in order to give the output "green" when input the wavelength 550nm. A device can directly detect an input wavelength but only has indirect information about its colour.
5. If colors exist in the mind, why did scientist study light and color that is independent of the human? — Richard B
Colour can refer to two different things. In sense one, it can refer to the private subjective feeling within the mind that cannot be described, as explained by Wittgenstein's Beetle in the Box analogy. In sense two, it can refer to the public name "green", "yellow" etc as used in the language game, the physical object, the physical name "green" that you see on the screen in front of you.
In sense one, colour only exists in the mind and not the world. In sense two, wavelengths only exist in the world and not the mind. Sense one and two are linked because the reason that we perceive colour in our mind is due to the fact that wavelengths exist in the world.
Scientists can measure physical things that exist in the world, such as wavelengths and language expressed either verbally or in writing. After all, the word "green" you see on your screen is a physical object that exists in the world. Scientists can measure pain-behaviour, which are physical events in the world, but not the pain itself that caused the pain-behaviour.
Wittgenstein writes in PI 244
A child has hurt himself and he cries; and then adults talk to him and teach him exclamations and, later, sentences. They teach the child new pain-behaviour. "So you are saying that the word 'pain' really means crying?"— On the contrary: the verbal expression of pain replaces crying and does not describe it.
But as a story of entertaining fiction, I do get a good laugh. — Richard B
If philosophy was meant to be fun, it would be being promoted at the Edinburgh Fringe Festival.
:smile: