[Right Wing Professor]

Is this text green? would you care to enlighten me, so the speak, with an objective definition of green that covers all cases in which people call something green in color?

Better make sure to cover the 10% of men who are red-green colorblind, too!

[Alamo-Girl]

Thank you so much for your great illustration of the case in point!

Is green a figment of your individual imagination - or a universal?

I say it is a universal (except of course to the color blind men as RWP asserts cannot see that particular universal) - and thus, even with preschoolers, I could instruct them to color the grass green on handouts without having to first teach them to read the wrapper on the crayon.

[js1138]

I suppose we could pick a wavelength and call that Platonic Green. I wonder if I could trademark that?

But in real life, objects, including light emitters, are pretty complex. I can even construct a spinning object with "black and white" stripes that appears green, even in monochromatic light.

And, of course, green pigments are usually mixtures of non-green pigments.

Green is a construct of the eye and brain. The Benham Top demonstrates that color is encoded by the retina as a firing rate for neurons. When you induce the firing rate with a non-chromatic pulsating light source, you get the subjective sense of color. I've done this under carefully controlled laboratory conditions, using a monochromatic light source.