Chidi reports having seen something which Michael declares to be the "time-knife", to which Chidi exclaims "I saw the time-knife" as if it was some non-visualized abstract concept he was already acquainted with. This leads me to ask: what is the time-knife as referenced in the show?

  • Is it a real concept in physics, philosophy, or some other real-world discipline?
  • Is it some sort of cultural reference?
  • Is it an in-joke?
  • Is it just some invention of the scriptwriters to give Chidi something to freak out over?
  • He says "What I was saying before, you know, I SAW THE TIME-KNIFE!", not "That was the time-knife?" He's just freaking out. There's no suggestion that it's a concept he's familiar with in-universe. Jan 20, 2019 at 18:50
  • @AnthonyGrist Thanks for correcting the quote. Even with the correction, It still seems (to me at least) that he spoke it as if he had already been acquainted with the term prior to having the experience.
    – Anthony X
    Jan 20, 2019 at 19:24
  • For some reason the term reminded me of the subtle knife from Philip Pullman's His Dark Materials
    – Zommuter
    Apr 29, 2021 at 8:21

1 Answer 1


The "Time-Knife" is an in-universe created idea, a bunch of realities folding onto each other like a blade. Chidi saw it when he was "falling" in the IHOP, and Michael names it shortly thereafter.

After Janet rescues tiny Chidi from falling, the conversation goes like this:

Chidi: I just saw a trillion different realities folding onto each other like thin sheets of metal forming a single blade.

Michael: Oh, that's the Time-Knife. We’ve all seen it.

It's not until afterwards that Chidi exclaims "I saw the Time-Knife!".

He might have seemed familiar with it since he'd already described it like a blade, but he definitely learned the phrase itself from Michael based on what he observed.

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