I've only seen the first movie, so apologies if later movies explain this.

In the first movie, presumably, through the butterfly effect, major world events would change due to Bill and Ted's kidnapping of historical figures and other interference. However, every time the duo returns to San Dimas, there is no evidence of historical events changing - for example, the history report makes perfect sense to the audience.

It's shown that changes in the past effect the present by Ted's trick with the keys and the other shenanigans at the police station - and the fact that Rufus had to go back in time to help Bill and Ted create the utopia of Rufus's time - so why didn't any major world events change up until at least 1988?

  • 3
    Because they put everyone back (except the princesses)
    – Valorum
    Jun 26, 2021 at 18:36
  • @Valorum True, but wouldn't there still be a significant risk of a butterfly effect? Small changes are still changes and could lead to bigger changes.
    – qarz
    Jun 26, 2021 at 18:42
  • 14
    The only place the 'butterfly effect' truly applies in in the film 'The Butterfly Effect'. Elsewhere time travel works however the writer wants it to work
    – Valorum
    Jun 26, 2021 at 18:48
  • 5
    Note that watching the two subsequent movies is not going to help you understand the time travel rules of films that were written largely for comedic effect. There is zero consistency between them (or even internally in the same films). It's just a bunch of stuff that happens.
    – Valorum
    Jun 26, 2021 at 19:25

2 Answers 2


There were no major changes to history because there were likely no changes whatsoever.

Bill & Ted's Excellent Adventure appears to adhere to Novikov's self-consistency principle, whereby the effects of any actions undertaken by a time traveller within their own past will already have been baked into the timeline to begin with.

The keys you mentioned are a perfect example of this. In the same scene where Ted comes up with the idea to steal his dad's keys, he remarks that those keys have already been missing for two days. He knows this because his dad told him the keys were missing in an earlier scene, and asked him if he'd done anything with them. Ted subsequently concludes that he had done something with them (i.e. stolen them)... or rather, his future self had.

Bill: How'd it go?

Ted: Bad. Our historical figures are all locked up and my dad won't let 'em out.

Bill: Can we get your dad's keys?

Ted: Could steal 'em, but he lost 'em two days ago.

Bill: If only we could go back in time to when he had 'em and steal 'em then.

Ted: Well, why can't we?

Bill: 'Cause we don't got time!

Ted: We could do it after the report!

Bill: Ted! Good thinking, dude! After the report, we'll time travel back to two days ago, steal your dad's keys, and leave 'em here!

Ted: Where?

Bill: I don't know. How about behind that sign? That way, when we get here now, they'll be waiting for us. See?!

Ted: Whoa! Yeah! So, after the report we can't forget to do this, otherwise it won't happen. But it did happen! Hey, it was me who stole my dad's keys!

Bill: Exactly, Ted! Come on!

This is a textbook case of the past being affected by a future that hadn't happened yet (from the perspective of those living in the present), and we see an even clearer example of this when Bill & Ted meet their future selves outside of the Circle K convenience store.

We first see this scene around 15 minutes into the movie, from the perspective of the slightly younger versions of Bill & Ted. Around forty minutes later, we see the same scene again, but this time from the perspective of the slightly older versions. As far as we're shown (the movie skips over part of the conversation the second time around), the two versions of the scene play out exactly the same way, just from different perspectives.

What the younger Bill & Ted saw then was essentially a preview of their own future, and not a possible future to be clear, but the actual future (from their perspective) that would definitely and verifiably happen.

Now consider everything Bill & Ted did during the roughly forty minutes of runtime between the two versions of that scene. That's the very window within which they plucked all the historical figures (Abraham Lincoln, Genghis Khan, etc) from their respective time periods, and brought them to 1988.

The fact that the younger versions of Bill & Ted were able to meet the older versions of themselves who'd already performed those actions before they (the younger Bill & Ted) subsequently went ahead and did the same thing is another strong indication that they didn't change anything by going back in time. They were just bringing things full circle, ensuring that the past unfolded the same way it already had done, which is a central feature of Novikov's self-consistency principle, and a necessity in order to avoid any grandfather paradoxes.

We get a third good example of this at the end of the movie, when Rufus brings the English princesses, Joanna and Elizabeth, to 1988. At this point, Rufus reveals that the princesses were part of the band themselves.

Rufus: Hello again, my excellent friends.

Bill: Whoa!

Rufus: Congratulations on passing your history report.

Ted: Rufus! The babes! We looked all over England for you!

Bill: Where'd you get those savory clothes?

Princess Joanna: Rufus introduced us to a place called the mall!

Princess Elizabeth: And something called credit cards!

Rufus: I got them out of England just before they had to marry those royal ugly dudes.

Ted: Oh, way to go Rufus!

Bill: How can we ever thank you, Rufus?

Rufus: Well, you can start by signing this for my kids.

Ted: Why?

Rufus: They're big fans of yours!

Bill: What?

Rufus: Everyone is. Wyld Stallyns' music has become the foundation of our whole society.

Bill & Ted (simultaneously): No way!

Rufus: Yes way! In fact, I believe you were there. That futuristic place with the domes?

Bill: And the totally excellent music!

Ted: They totally worshipped us there, Rufus!

Rufus: I know! That's why I was sent to make sure you passed your history report. If you guys were separated it would've been disastrous for life as we know it. You see, eventually, your music will help put an end to war and poverty. It will align the planets and bring them into universal harmony, allowing meaningful contact with all forms of life, from extraterrestrial beings to common household pets. And... it's excellent for dancing.

Bill: Whoa.

Rufus: Why don't you have the ladies sign as well, would you please? After all, they are in the band.

Bill: They are?

Ted: Excellent!

This again implies that their (permanent) displacement from the 15th century to the 20th and 21st centuries didn't strictly alter history. That event was already baked into the timeline all along, and part of the existing history from Rufus' perspective. He didn't come back in time to change history, but to ensure that it happened the way it was 'supposed' to, as far as the historical records of his time period were concerned.

  • 5
    Bill & Ted, the only film to do time travel right.
    – James K
    Jun 27, 2021 at 18:22
  • 1
    You might wish to note that this is subverted in the subsequent films. Bill and Ted unite all the timelines, both past and present, but only once they've done it. The clock in San Dimas seems to be the only one that really counts.
    – Valorum
    Jun 27, 2021 at 19:52
  • @Valorum - That's certainly the case in Face the Music. I'm not sure Bogus Journey strictly contradicts the self-consistent interpretation of the first film though. Chuck De Nomolos clearly wanted to alter history, but it's not clear if he actually could or did. He inadvertently ends up creating what Seven of Nine would call a Pogo paradox, since he brings about the conditions that allow TV viewers around the world to watch the Battle of the Bands. Without his intervention, it presumably wouldn't have been the global event that it was. Jun 28, 2021 at 14:20

At the end of the film, Bill and his esteemed colleague Ted are most careful to return the various historic personages to their correct places in time. Since the consequences of (for example) Abraham Lincoln not giving the Gettysburg Address would be most heinous, it's essential that each person is put back into the timestream where they came from. Note that in the original script it was pretty clear that this entire film is a fixed loop, with each person playing out their assigned role.

BILL: Don't tell me we forgot the ladder!

TED: (pounding his head): Remember the ladder. Remember the ladder. Remem --

BILL: (interrupting) Ted -- it doesn't matter. If it's not there now, we're not gonna do it, so you don't gotta remember.

TED: I don't gotta remember? Excellent! (Ted does AIR GUITAR)


BILL: Did we put everything in the right place at the police station?

TED: Yah, I think so. (beat) We forgot the ladder ...

BILL: That's OK.

As to whether and why each person who's been hanging around the time travelers isn't then influenced by what they've seen, the answer is that most of them have been kept pretty well isolated from outside influences that may affect their actions. Napoleon is the only one who spent significant time in the future of San Dimas and he mainly indulged his passions for food and waterslides rather than (more sensibly) spending time in the library perusing a copy of Steven T. Ross' European Diplomatic History, 1789–1815.

  • 1
    Also, Napoleon's experience in San Dimas led him to have an affinity for going to a place called "Waterloo". So they did have an effect, it was just one that put them on the path of the historical events we know today. Jun 27, 2021 at 16:03
  • @JerrySchirmer - I always assumed that was a coincidence.
    – Valorum
    Jun 27, 2021 at 16:16
  • 2
    A most excellent answer!
    – StephenS
    Jun 27, 2021 at 20:04
  • @StephenS - And a most non-heinous acceptance.
    – Valorum
    Jun 27, 2021 at 20:04

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