To blame computers is human

I’ve read many variants on the parodic proverb “to err is human; to really foul things up requires a computer”, mostly cheaply printed on mugs and tshirts (and often using somewhat coarser language), and had assumed it was relatively recent, but the other day I stumbled across the meme in a rather surprising place:

“Do you know what you sound like?” said Mrs. Oliver. “A computer. You know. You’re programming yourself. That’s what they call it, isn’t it? I mean you’re feeding all these things into yourself all day and then you’re going to see what comes out.”

“It is certainly an idea you have there,” said Poirot, with some interest. “Yes, yes, I play the part of the computer. One feeds in the information—”

“And supposing you come up with all the wrong answers?” said Mrs. Oliver.

“That would be impossible,” said Hercule Poirot. “Computers do not do that sort of a thing.”

“They’re not supposed to,” said Mrs. Oliver, “but you’d be surprised at the things that happen sometimes. My last electric light bill, for instance. I know there’s a proverb which says ‘To err is human,’ but a human error is nothing to what a computer can do if it tries.”

—Agatha Christie, Hallowe’en Party (1969)

[This text appears on pp.38-39 of the 1971 Fontana paperback edition]

I wondered if this was a particularly early attestation, so turned to (of course) more computers for the answer. The ever-helpful Quote Investigator gave April 1969 as their earliest cite for this saying; Christie’s novel was first published in November 1969, so my discovery didn’t push their date back, but it was still interesting, both as a question of provenance and an insight into “computer culture”. Had Christie read it and remembered it? Did she independently come up with the same idea? Did Bill Vaughan (whom QI credits with penning the proverb) just write down something that was already common currency by this point? We tend to think that eye-rolling exasperation with computers is a modern affliction, the contempt born of familiarity, but it was clearly unremarkable enough to find its way into Christie’s bag of clichés over 40 years ago. I’m actually surprised the quote hasn’t yet been attributed to Cicero, or some long-forgotten pre-modern scribe on his ancient tablet (perhaps a Newton MessagePad).