Talk:all cats are grey in the dark

The provided explanation is incorrect
The correct explanation is that people have long known that color vision disappears under low-light condition (try telling the color of various stars - you can't, except for a few very bright ones, and some of our planets), and now we know that is so because the "cones" in our retina see color, but are not that light-sensitive, whereas the "rods" just see light (not color), but are much more light-sensitive. So at night, or in general, when it is dark, we lose color vision, and "all cats look gray" (also a German phrase, where its meaning may be more generally understood among the population).
 * I was just thinking this seemed a plausible explanation as well. But can you be sure the given etymology is incorrect?  It seems to me that, in reality, it's a combination of the two – because as you rightly say our colour vision doesn't work well in dim light, things will tend to look grey, thus the given etymology compares this to the typical hair of an older person.  That said, this reinforces another question: Why does it refer to cats in particular? — Smjg (talk) 09:45, 23 April 2021 (UTC)

Too narrow definition?
I think the phrase is often used in a much more figurative sense, of all kinds of situations where differences that actually exist are blurred or no longer discernible. Say, you're a very bad student and so you fail your test, but then the test had been made much too difficult and even the good students fail. There may be better examples, but yeah, situation like these. 92.218.236.35 17:24, 8 April 2020 (UTC)

Indian English
Indian collections of English proverbs seem to something like
 * Commoners are all the same, those without fame or nobility are indistinguishable.

which is a reasonable gloss of a potential meaning but doesn't seem to actually be used in the wild, as far as I can tell. If those books have shaped Indian usage or cites can show that people use the expression that way, though, it could be added back in. — LlywelynII  01:41, 2 May 2022 (UTC)