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I don't think this really has anything to do with science so I posted

  1. Sep 16, 2011 #1
    I don't think this really has anything to do with science so I posted it here. It's a strange question, but I want to know what you guys think.

    Many things can be said to have two extremes... as in positive and negative. In this sense, 0 would be "between" -10 and 10.

    If you have three extremes instead of two, can any one of them said to be "between" the other two? For example, can yellow said to be between blue and red? With each of the colors being their own extreme, of course.

    Also does this question even make sense?
  2. jcsd
  3. Sep 16, 2011 #2
    Re: Extremes

    The premise, that you have three extremes, is false. You have a continuum, the color spectrum of visible light, yellow is in the middle; red and blue are the extremes. If you added another axis at right angles to the first, the axis of light and dark (grey in the middle, white and black at the extremes) then you'd have four extremes. I can't think of a way to end up with an odd number of extremes.
  4. Sep 16, 2011 #3


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    Re: Extremes

    No. None of your extremes (red, yellow, blue) can be between the other extremes because they are extremes. In this case, black would be between your extremes.

    If you were using the additive primary colors instead of the subractive primary colors, then white would be between your extremes of red, green, and blue.

    And, yes, you can have odd number of extremes in the real world, even though it might seem strange mathematically (or spectrally, in this case, since if you're looking at the frequencies of light, yellow does indeed lie between red and blue). In the case of 3 extremes (3 primary colors), it's because humans are trichromatic. We have three types of color receptors (cones), hence we perceive 3 primary colors, even if those primary colors have been hard to define at times. The differences between the additive properties, the subtractive properties, and the realization that colors were just a given frequency of electromagnetic waves has caused a lot of flux in how we define primary colors; so much so that I'm not really sure it's still appropriate to say the primary colors are "extremes".
  5. Sep 16, 2011 #4


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    Re: Extremes

    What you are talking about is a general rule of nature and logic. To definitely have one thing, you must definitely have its other as well. We call this complementary properties, dichotomies, thesis/antithesis, symmetry breaking, etc.

    So for the idea of the continuous to make sense, you need the idea of the discrete as its precise opposite. Same with chance and necessity, or stasis and flux, or figure and ground, or atom and void.

    Just two polar extremes is the rule because three or more extremes would be unstable.

    Human vision is an interesting example of this. The receptors of the retina are set up with a variety of opponent processes - dichotomous receptive fields.

    So for instance, to help with edge detection, light falling at the central spot will cause a cell to fire strongly, whereas light at the edge of its field will turn it right off.

    The same kind of opponent processing principle happens all the way up. The experience of colour is created via opponent responses, with red being complementary to green and blue to yellow. As can be told by afterimages, red equals not-blue, and vice versa.

    The importance of having complementary responses to create a high contrast experience is demonstrated by the fact the visual pathways have to invent yellow as a complementary colour for blue.

    You only have three kinds of wavelength responsive cones, with no "yellow" one. But there is then a mixing of green/red information to manufacture a hue to stand as an opponent to blue.

    So yellow is between red and green, and opposite to blue. Each is extreme because you can't get the experience of yellowish-blue or reddish-green (but can get reddish-yellow, etc).

    Light and dark, or luminance, is also an opponent process of course. And so black and white can mix with these hues to make colour experience very complex.

    But the basic dichotomous principles are revealed in many subtle ways. Such as that you can have the experience of blackish green, red or blue, but not yellow. Blackish yellow looks brown. Something different is experienced because of the more derived way yellow is created in the visual pathways.
  6. Sep 16, 2011 #5
    Re: Extremes

    In English, 'between' is used when there are two things. The 'tween' actually comes from the word two. Use 'among' when there are three or more things.
  7. Sep 16, 2011 #6


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    Re: Extremes

    "Color space"

    image details at http://en.wikipedia.org/wiki/File:Colorspace.png" [Broken]
    Last edited by a moderator: May 5, 2017
  8. Sep 16, 2011 #7
    Re: Extremes

    Words only have demonstrable meaning according to their function in specific contexts. In other words, you make up whatever meaning you want.
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