At 3/23/08 05:01 PM, Coaly wrote:
At 3/23/08 04:42 PM, DougyTheFreshmaker wrote:
Thus, the apple *looks* red, but in actuality, if anything can be said *for certain*, it is that a red apple is definitely not red.That's a pretty silly conclusion. If your point is that since the red apple reflects red light, it isn't red, then you're thinking about why we call it red in the wrong way, the fact the it reflects that color of light back to us is the sole reason we call it that color....so if anything can be said for certain, it is that a red apple is definitely red, because the conditions for it being called a red apple are defined by humans.
I was mostly building on "the color red" joke :p
But yes, there's a lot of assumption and semantics behind most "regular human things". If you assume a human, and assume this magically defined criteria for what a human considers a color, then I guess an apple "is" red. A bee, for example, perceives light centered around an entirely different part of the spectrum, and wouldn't agree with our definition of "red".
I think the signal to noise ratio is pretty low for colloquial speak, but I'm not rallying against it or anything. It's a lot easier to say 'this apple is red' rather than 'this apple reflects light in the red part of the spectrum as observed by humans'. It's easier to say 'the sky is blue' rather than 'the sky appears blue because of atmospheric scattering'.
the fact the it reflects that color of light back to us is the sole reason we call it that color
This is wrong because if you consider, say, an apple displayed on a monitor, you see that the monitor essentially generates the red light that we see--it doesn't really reflect anything. So a photograph of an apple displayed on a monitor probably might be considered to 'actually' be red because it 'actually' emits red light, but the actual apple in the photograph is just perceived as being red.
So you might say that things "are" a certain color if humans perceive them as being that color, but only under specific circumstances.
For example, if you had an apple sitting on the floor in a closed room, you would see it as red. If the lights were turned off, is it STILL a red apple? What would you say? Yes? No? Probably yes, because it has the 'potential' to be a red apple under normal lighting conditions. In fact, an apple in a completely dark room, when observed by a human, is completely invisible. Would you feel comfortable saying that objects in a room with no light sources are completely invisible (think about the word "invisible")? If the apple were placed under ultraviolet light only, it'd probably look blue--does that make the apple blue? Or is it still red because under "ordinary Sun circumstances" humans perceive it as being red?