"At night, all cats are black."

The Ruth Rendell mysteries have made themselves available on Amazon Prime Video. We started with the first one, the wife and I. Master of the Moor, in three parts, 50 minutes each. By the time we got to the end of part one, the wife said "Well I'll stick with it to see how it turns out, but I'm not watching any more of them." Me, too. We finished the three-parter and that was enough of that.

But somewhere in Part Three there was one good line: "At night, all cats are black." To me it meant: When you can't see what makes them different, they all look the same.

I thought that was a useful phrase. I often find myself thinking this is the same as that in economics. Then I read a little more, and it's like somebody turned on the light: Oh, I see, they are different!

But I wasn't really sure if that was how the phrase was used in the Ruth Rendell story. So I googled it. It came back the same phrase, but with gray in place of black. And apparently it was Ben Franklin's "endorsement of older women to a horny young man", according to the Huffington Post. Because older women don't look bad in the dark? So, that's not what I thought it meant.

I bit the bullet and sat down to watch Part Three again. Got it. It starts around 42:44 into the episode.

Cop#1 (comparing photos of three murder victims): There's something about this last one. It doesn't fit.

Cop #2: What?

Cop#1: I dunno. Can't put my finger on it. But something.

Cop#2: They're identical.

Cop#1 (turns to look at cop#2): At night, all cats are black.


What I said. When you can't see what makes them different, they all look the same.