Perhaps one of the oldest philosophical questions goes something like this: “Why are objects the colour they are?”
There are three main approaches to this. The first is to treat colour as a property of the object being observed. The second treats colour as a property of light. And a third approach treats colour as a mode of perception.
In the 17th century, Isaac Newton performed a series of brilliant experiments on light. He shone white light through a prism and showed that you can separate it into rays of different coloured light. He took this to mean that colour is an intrinsic property of light.
When combined with his theory of light which treated light as a series of particles, this led him to believe there were different sizes of particles corresponding to different colours. Blue is the result of particles of a certain size. Red is the result of particles of a different size and so forth.
So, Is Colour in The Light?
This has led many people to conclude that colour is a property intrinsic to light. As though light has a property of “blueness” or “redness”.
Many people still talk as though they believe that colour is a property of light. For instance, when people say something like:
“Look at that light, it is blue light.”
However, this is not the case. Light does not have a property of “blueness” or “redness” or any other colour. There is no property of light which corresponds directly to colour. However, there is a property of light which causes the perception of certain colours, as we shall see in a moment.
So, there is no property of colour in light. You can study light all you want; you will not find this property. Suppose you could isolate a single photon (whatever that is) and study every aspect of it. But you will never find a quality of “blueness” or “redness”. No matter how hard you look. Nobody ever has and you should not expect anyone to ever do so. So, what does that mean?
Is Colour in the Object?
Prior to the idea that colour is in the light, it was widely believed that colour is “in the object” being perceived. It was believed that apples were red because of some kind of “redness” in the apples. In other words, an apple appears red because it has some property of redness. The sky appears blue because it has some property of blueness. As though if you studied the properties of things, you could find a “colour” property or attribute. Or, as though colour is “in the object”.
Many people still seem to think that colour is an attribute or property of an object. You can see this when they say things like:
“That apple has a lot of redness in it.”
But this is also wrong. Colour is not “in the object” nor is it “in the light”. Colour is a form of perception which depends on the nature of the objects being observed. As well as the nature of the light interacting with the human eye. Colour is a result of an interaction between the eye and the light being emitted or reflected from the object being observed.
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