Professor Hubert Farnsworth: You mustn't interfere with the past. Don't do anything that affects anything. Unless it turns out that you were supposed to do it; in which case, for the love of God, don't not do it!
Fry: Got it.
Professor Hubert Farnsworth: If, for example, you were to kill your grandfather, you would cease to exist.
Fry: [gasp] But existing is basically all I do!
— Futurama, "Roswell That Ends Well"
Bosco: I still feel kind of distant. What did you guys do?
Sam: We kind of made it so you've never been born. Whoops.
Bosco: But being born was one of the greatest things I ever did!
— Sam & Max: Beyond Time and Space, Chariots of the Dogs
Donna: You saved me, in 2008; you saved us all! Why is this different?
Doctor: Some things are fixed, some things are in flux. Pompeii is fixed.
Donna: How do you know which is which?
Doctor: Because that's how I see the universe. Every waking second, I can see. What is, what was, what could be, what must not. That's the burden of the Time Lord, Donna. And I'm the only one left.
Doctor: Some things are fixed, some things are in flux. Pompeii is fixed.
Donna: How do you know which is which?
Doctor: Because that's how I see the universe. Every waking second, I can see. What is, what was, what could be, what must not. That's the burden of the Time Lord, Donna. And I'm the only one left.
- Doctor Who, "The Fires of Pompeii"
I think certain moments in time...are fixed. Tiny, precious moments. Everything else is in flux, anything can happen - but those certain moments, they have to stand. This base on Mars, with you, Adelaide Brooke, this is one vital moment. What happens here must always happen.
— The Tenth Doctor, Doctor Who, "The Waters of Mars"
There are fixed points throughout time where things must stay exactly the way they are. This is not one of them. This is an opportunity. Whatever happens here will create its own timeline, its own reality, a temporal tipping point.
— The Eleventh Doctor, "Cold Blood"
There are some moments in time that I simply can’t see. Little eye-blinks. They don’t look the same as other things. They’re not clear. They’re fuzzy. They’re gray. Little moments in which big things are decided. And this is one of them.
— The Twelfth Doctor, "Kill the Moon"
"The question that once haunted my being has been answered. The future is not fixed, and my choices are my own. And yet, how ironic... for I now find that I have no choice at all! [transforms and draws weapons] I am a warrior... Let the battle be joined..."
— Dinobot, Beast Wars, "Code of Hero"
Harvey: All modern research points to the elasticity of time, rather than a brittle framework.
Crichton: Can it be corrected?
Harvey: If nudged closely enough to course, events have a way of restructuring themselves. If the participants are the same, the venue's the same, the motivation's the same, then well: the outcome is likely to be the same.
— Farscape, "Different Destinations"
Deke: Yeah, the butterfly effect is just one aspect of the Multiverse Branch Theory. Personally, I subscribe to the timestream idea.
Daisy: Let me guess, that's the one that lets you do whatever you want.
Deke: Okay, imagine time is a stream, right? And we were sticks that were thrown into it. The water, it moves us, it moves around us—
Coulson: But it ends up in the same place.
Deke: Right! Now too many sticks thrown in and that'll create what's called a dam, and that'll change the direction of the water forever and that's bad. So as long as we can avoid that we should be able to splash around a little bit and we're all good.
Mack: Ripples, not waves.
Daisy: Let me guess, that's the one that lets you do whatever you want.
Deke: Okay, imagine time is a stream, right? And we were sticks that were thrown into it. The water, it moves us, it moves around us—
Coulson: But it ends up in the same place.
Deke: Right! Now too many sticks thrown in and that'll create what's called a dam, and that'll change the direction of the water forever and that's bad. So as long as we can avoid that we should be able to splash around a little bit and we're all good.
Mack: Ripples, not waves.
