Thanks for the Humboldt reference, haven't been that way and did not know of it. I'd guess it is a fairly common doubt, I remember wondering, as a schoolboy, if

Thanks for the Humboldt reference, haven't been that way and did not know of it. I'd guess it is a fairly common doubt, I remember wondering, as a schoolboy, if what everyone called green was perceived identically. All this ends up being a centuries long conversation, and the current reference is merely the latest overlay. For instance, Wittgenstein mentioned that one must "throw away the ladder after he has climbed up it", riffing on Schopenhauer's scorn of those who carried books on their backs instead of leaving them behind as climbed ladder steps, and apparently it was Plato who spread the idea that there was a knowledge ladder to be climbed ...