angel eyes

Joe Carter, fresh off a long, exhausting conversation with my brother (been there, Joe), writes:

One of the questions we addressed was whether blind people could know the form of the color Green since they could not perceive it with their senses. Matt responded matter-of-factly that angels don't have eyes either and yet they can know the color green. (The ability to make such dogmatic, brilliant, and utterly absurd claims with a completely straight face is one of the many reasons I love the guy.) But Matt's claim goes even further. His position is not only that angels can see green but that the "form" green existed even before there were men or angels to perceive colors at all.

Ah, but can angels see grue--or, for that matter, bleen?