- [upbeat electronic music] - Greetings, and welcome to Ars Live "Time Travel in the Movies." I'm Jennifer Ouellette. I'm a senior writer at "Ars Technica" for science and culture, and I'm delighted to welcome my panelists for today. First is Sean Carroll. He's the Homewood Professor of Natural Philosophy at Johns Hopkins University, and, full disclosure, also, we're married. [laughs] Second, we have Jim Kakalios, who is a professor at the University of Minnesota and the author of such popular science books as "The Physics of Superheroes," and last but certainly not least, we have Ed Solomon, who's a writer and producer and is probably best known to you all for "Bill & Ted's Excellent Adventure" and its subsequent sequels. Welcome, everybody, and thank you so much for joining me. - Thank you for having me. - Thanks, Jennifer. - Also, Jennifer and I are dating, but Sean- [Jennifer laughs] - Well, don't tell Sean. - She said that her Sean were married. She didn't say to each other, just married. - Oh, it's gonna be a long hour. - It is, it is. [laughs] So the impetus for this discussion stems from a long piece that Sean and I wrote last fall, "The Ars Guide to Time Travel in the Movies," and then in turn came out of the fact that Sean and I routinely talk about time travel when we watch films and televisions, and Sean, being a physicist, has very strong opinions about what it should and should not look like in creative endeavors. And so I think that's a good starting off point because it's Sean's favorite, you know, ax to grind. You have a certain criteria for what you think time travel, logical time travel should be, and so let's start there with you kind of giving a brief summation. - Yeah, I once wrote a blog post called "Rules for Time Travelers," and I read it over in preparation for this. It's way too long. There's too many rules. I'm not gonna give you all those rules, but the short version is, you know, traveling in time is easy as long as you just go to the future. Yesterday, I travel in time 24 hours, and here I am right now, and Einstein showed us that you can sort of get there more quickly by going close to the speed of light or hanging out near black holes. What's hard or maybe impossible is going to the past. We have theoretical ways of doing it. We have no practical, realistic ways of doing it. It might just be impossible. We think, though, if you could go to the past, there are a few rules. One is that you shouldn't be able to change the past. So you can go and try to prevent JFK from being assassinated. You will fail because we know he got assassinated. We don't know why you will fail, but we know it's not going to work. Also, you can't go earlier than the day you built the time machine for the first place. So that prevents a lot of scenarios that people think about. You could find a time machine that someone else built and then maybe use it for other purposes, but those are the rules that physics seems to lay down, the final one being, of course, a footnote. If you allow for parallel universes, if you allow for alternate timelines, which physics is happy with, in principle that could happen, then all bets are off. Then you could go to a different universe where things are similar but not the same, change things because you don't know how they turn out. So the real rule for time travelers is only go to the future, but if you do go to the past, there's a certain set of things to keep in mind. - So Jim, you're also a physicist. - What do you hate though? - What? - Oh, sorry. No, I'll get to that later. I'm writing my questions. - What do I hate? - Can I say what I hate? - Oh, no, we can get to that. I don't wanna cut Jim off, so, you know. - We are gonna get to what he hates, - Oh, okay. - and he hates "Back to the Future." [laughs] - So much hate. - Ooh, interesting. - But I wanna also have Jim weigh in. He's a fellow physicist, but Jim, do you agree with what Sean said, or do you think that there were some loopholes? I mean, do you have- - Well, okay, I have one rule about time travel, time travel movies that I think Ed will agree with here as a screenwriter. The shorter the time travel trip, the shorter in time, the easier it is to make the movie on a really small budget. [everyone laughs] I might get the title of this movie wrong, but I just saw a couple of days ago "The Infinite Two Minutes," which is someone has a coffee shop in Japan. He goes to his apartment above it, and he's looking at his monitor, and himself from two minutes in the future is talking to him and he finds that when he can go back and forth between these two monitors, he's constantly flipping two minutes. It turns into a really, really sweet story. People try to exploit it. There's gangsters. There's all sorts of stuff. You would think that two minutes is not enough to actually do something, but then they do some clever things, like they set up a series of monitors so they can go two minutes, four minutes, eight minutes, and so on. The thing that struck me was that it was a really interesting movie, and it was clear that it cost like a buck 65, [everyone laughs] and I don't mean 1.65 million. I think it was shot on an iPhone or something, and so anyway, yeah, my basic rule is I don't sweat too much as the physics of it as long as it doesn't do anything so egregious that it takes me out of the story. So what I want is I want the physics to be good enough that I don't start questioning what I'm watching 'cause I don't go to the theater with a pen and paper and a calculator and say, "Ooh, my physics sense is tingling." But, you know, if they get it really wrong, then you're out of the movie, and then it makes it a bad movie, yep. - I always think of two forms of physics in the time travel movies but really in any science fiction. The first is actual physics, what's possible, and the question is, and that's a big one to discuss because like what can really happen, and how many buys do you give the audience? Like how much do you say, "Well this couldn't really happen, but we're gonna do it anyway"? This couldn't really happen. How far in the future is it so that you might believe this could happen? And to me, that is an intuitive thing, like this wouldn't really happen, but I believe it could if the following things occurred. Well, that's okay, but in terms of specifically for time travel to me, there's two kinds of physics for movies or all science fiction. One is actual physics, as I was saying, real rules, but the other one is the physics of the movie itself 'cause I actually think that, really, it kind of all works if fiction in my mind have their own rules and their own internal physics, and we often would say, whether it was "Bill & Ted" or other things I've worked on, "Are we breaking the rules of the physics of this movie?" You know, and the other thing I would say, Jim, about when you're writing a time travel movie or conceiving of a time travel idea, going back for a short amount of time, it's not just a budget thing. [Jim laughs] You don't have to deal with as much of that, like how much is being changed? What's the sort of temporal butterfly effect, you know, that's gonna happen going forward? And in "Bill & Ted," that was one thing that we tried to just dance around because the truth is, you know, if you can time travel and you're [laughs] just gonna do it to pass a history test and actually can do that, like is that really the best use of this technology you've just been given? And so there is one other thing that I think applies to all science fiction. In fact, in "Men in Black," I got into a vociferous argument with Tommy Lee Jones about this in our very first meeting wherein he called me, am I allowed to swear, Jennifer, on this? - I don't care, but maybe- - Go for it. - He called me an a-hole. How about that? [everyone laughs] Which stands for, no. [everyone laughs] Because he was like, "It's either comedy or it's science fiction. Make up your mind," and then he used his word. And it was the very first meeting, too, and the head of the studio was there 'cause he had just won "The Fugitive" Oscar. And the head of the studio is like, "Yeah, it's either comedy or science fiction, right?" And I was like, it's isn't good enough science fiction to be a drama, it's just not. You need the leap of faith that comedy will provide, and so to me, that sort of third thing in constructing science fiction of any kind is what's the mood of the movie? Because of the mood is the envelope within which everyone will accept the movie's physics in and of itself. That mood is like the ether cloud that you're living in when you're going to a movie. So Jim isn't there with his clipboard going, "Obviously, that actually wouldn't entirely occur." - No, that's that's an excellent point because making it a comedy kind of gives you permission to not take it super seriously. It says like, "Yeah, we know that this is not rigorous. Relax. It's a movie." [Sean laughs] - You know, it's funny- - When "Tenet" came out- Sorry Jennifer, I'll just- - Go ahead. - When "Tenet" and "Bill & Ted" came out basically around the same time, I was like, "You can see a serious meditation on the physics of time travel, or you could see 'Tenet.'" So, you know, anyway, sorry. [everyone laughs] - That's very funny. No, I was just gonna say that, you know, eons ago, I was a big "Buffy the Vampire Slayer" fan, so much so that I wrote an entire book on the physics of the Buffy verse, and Ed, this gets back to what you were saying. It's not that the Buffyverse has good physics by our standards. It has its own physics, and so I was kind of looking at, you know, is it consistent? And you know, not completely, not 100%, but actually pretty good, and so that was kind of my criteria. So I think it makes sense when you're talking about a fictional world. Is it internally consistent? Is it with its own rules? - 100%, and comedically, you know, are the right jokes because we had jokes in "Bill & Ted" in the roughest, roughest version of it that didn't fit with the kind of jokes that weren't even about time travel, but, it's like a key signature, and people may not be able to, you know, you might not be able to listen to, you know, a symphony in E minor and say, "That's E minor," but you'll know if a note is wrong or, you know, maybe not in the symphony, but you know what I mean. - Yeah, I love that metaphor, the key signature, but also I love the idea that jokes and physics have the same property, that they wanna be internally consistent. They wanna be a theme, they want to be, you know, on the same wavelength somehow. - And people go into both because they couldn't date much, I would say. - That's also high school. - Yeah, I would say there's a lot of similarity. - They were bullied. It's true, okay. - I wouldn't say much. I'd say at all. [everyone laughs] - Yeah, good point. It is, there's a crossroads. There's a certain inflection point, and it's like physics or comedy? Physics? - That's it. Those are the two. - It's the physics, comedy. - So I wanna talk a moment, this is about "Bill & Ted" because, you know, Ed, you might not know this, but "Bill & Ted" has Sean's single favorite example of time travel physics of like a perfect scene of time travel physics, and I'm gonna let Sean - Oh god dang it. - talk about that and then have you respond to Sean. - Ooh. - Yeah, the famous, "How do we get the keys?" It was the keys to the car, right? - Keys to get the historical figures out of jail. - To get outta out of jail, right. So you need the keys. You don't have enough time to do it 'cause there's a deadline. You know, things are happening quickly, and so many stories with time travel in them because it's a movie and there's drama, and there's, you know, stakes. People run outta time to do things, and I'm always sitting there thinking, "But you have a time machine. [laughs] How can you run outta time?" And "Bill & Ted" is the one time where they said, "But we have a time machine. How are we gonna run outta time? Let's wait till the future, go back to the past, get the keys, put them here." And I'm sure many of the listeners, viewers right now are very familiar with the scene, but the point is that sure, "Bill & Ted," just like "Back to the Future," many other time travel movies asks the audience to believe in the physics of time travel on its own terms, but you should always make logical sense, right? It should not be incompatible, in contradiction with things that have happened earlier, and that scene is 100% logically consistent, so hats off. - God dang it, thank you so much. I really appreciate that. For people who don't know the movie, the basic premise is, well, Bill and Ted are gonna fail a history report. Someone from the future shows up for reasons that turn out later in the film, yeah, and to help them with a time traveling phone booth, which used to be, it was a van, and then "Back to the Future" was gonna come out, and they're like, "Oh, they time travel in a car. You have to change it." So the director had the idea to turn that into a phone booth, whatever. So he shows up with a phone booth. They can now travel through time. They go collecting historical figures for their history report and bring 'em back, but everything goes kind of haywire, and they lose them in a mall, and they ended up getting arrested, and Bill and Ted had to get 'em out of a jail. But the time machine that they've built, the phone booth is broken, so they're like, "How are we going to get them out of jail?" And so the premise of the scene was, "Well what about if, after the history report, we get the booth fixed, and after we fix the booth, we go back in time and we put things, we put keys here in the jail." Oh yeah, "We put my father's keys to," his father was a cop. "We put my dad's keys over here," and they go, "Well, how will we know if we did it?" They look and the keys are there, and they're like, "Well, we must've done that." - There you go. - And then the whole scene, the sequence is, "Okay, we need to get a bucket over here. Remember a bucket, remember a bucket," and then a bucket falls. "We need a ladder. Oh, there's no ladder. Oh, I must've forgotten the ladder. Okay, well then we keep going." And the bummer for me about that scene is it used to be four times as long 'cause it actually is my favorite scene of the three "Bill & Ted" movies. It's my favorite one, and the funny thing is there's actually no science fiction in that sequence at all, and the reason was we were, I remember, God, it was midnight. We had to turn the script in the next day. We were doing a rewrite. There was no budget for this movie. It was a very low budget film, and we had written ourselves into a corner. We'd written ourselves into jail. We'd written the historical figures into jail, and we had no creative way to get them out, and we were like trying to come, oh, and we were also told, "You can't use special effects. You can't use any action. You can't have stunts. [laughs] Basically get 'em out of jail in an interesting way," and we were like, it's quite literally the 11th hour. And I remember saying to Chris, "Well, what if they go, after the report, they go back and then do it?" And that led to that whole sequence, and the producers thought, "Audiences won't get it. It's too conceptual. Make it as short as you can." And I kind of bummed. They said that about my two favorite sequences in that movie. The other one was when another version of Bill and Ted show up and tell the first version of Bill and Ted, "You guys are gonna have an amazing time," and there was a much longer back and forth with them trying to, you know, "If you're really me, how do I know I'm you and," you know, all that stuff. Anyway, but thank you, Sean. I appreciate that. I didn't mean to hog- - A director's cut is what you're saying. - Well, I'll mention also very quickly, you know, Jennifer and I, as she said, we talk about time travel and movies and TV shows all the time. Jennifer's the science and culture writer at "Ars Technica." So we absolutely have a pitch for a time traveling detective TV show where the detective would go back and solve cases. And I was asked to consult on someone else had a time traveling detective TV show idea, and, you know, they said, "Okay, so the detective will go back, solve the case, and then go back to the future, and the case will be solved, and, you know, the murder will have been prevented." And I said to them, "But then who hired them to go back and solve the case? 'Cause there was no murder, there was no case, and so you should try to make it so that they can't change the past rather than they go and fix it." And their response was, "Well, if you can't change the past, why is it interesting?" And my response was, "They don't change the past in 'Law & Order,' right? You just find out what happened. It's still considered interesting." - Right. I conceived it as "Cold Case Files" meets time travel, you know, because you know who did it. It's a cold case or you don't know who did it but you know there's been a murder, and being able to go back in time helps you solve the cold case. I actually thought it would be great. Hollywood disagreed. [laughs] - I once had an idea. [laughs] I don't know why I was, I think it was completely baked outta my head, and I had an idea for an episode of "Curb Your Enthusiasm" that they would never make 'cause it involved time travel, which, of course, doesn't fit in. I apologize to anyone who might be offended by this idea. The idea was that Larry goes to the flea market. He goes to buy a hammock at the flea market, but he doesn't enough money. The guy says, "It's okay, just give me like $40, and come back and give me the other $40." So he goes to the ATM, but it's broken. He has to find another ATM, and his card gets taken, and by the time he gets back to the flea market to basically return the hammock, the guy's stall is gone, and now he thinks, "Oh my God, there's a guy who thinks I ripped him off. I didn't rip him off," and he's leaving the flea market, and somebody says, "Hey, I can help you out," and he has a thing called time cookie. He goes like, "Just buy this off me. I'm not using them. They're time cookies. You just eat one, and you can travel in time." And now it's like, then you cut to dinner, and they're having this whole argument about, "You have one chance to go back in time, and you're gonna use this to prove to some flea market guy that you're not an a-hole there." So there you go, Jennifer. - Callback. - And then it's like, you know, "Well, what are you gonna do then?" And they decided he's gonna be the guy that goes back to stop Hitler, and he's like, "I can't. Like the entire allied forces couldn't stop, you know, Hitler. You know, I can't do that myself," and they go, "Yeah, 'cause they went at the wrong time." So then you cut to this little schoolboy [laughs] going through the mountains of Austria, and he's an artist, and, you know, he's this little kid. [laughs] He's got all this material on what Hitler was going to be doing, and it's about him trying to murder this seven year old. [everyone laughs] Anyway, of course, it was- - That's a dark place. - Yeah, really. - It was just me. It was just me, I think, baked outta my head, kind of making myself laugh. - So Jim, I actually wanna talk to you about one of the- - [Ed] You're so sorry you had me on, aren't you? Sorry about that. [laughs] - No, no, not at all. We're delighted. - [Sean] We'll edit it out, don't worry. - No, no, no, that's gonna be my part coming up. - Jim, because you do physics of superheroes, I mean, one of the things on our list was Superman, the original one with Christopher Reeve, and we were very hard on the time travel technique in that one, very harsh in our criticism. I know you're very excited about this, where basically Superman brings back Lois Lane from the dead by essentially flying around the earth really fast in the opposite direction and making it turn the other way briefly. You know, and just, you know, from Sean's standpoint, utterly ludicrous, but you have some thoughts. - I've given this more thought than the average physics professor, [Ed laughs] and okay, so let's specify or get a few facts out. We can figure out how fast Superman is going as he's orbiting the earth because you see the earth. He's creating these like rings as he's going around, like these after images. So you can look, measure the height of that ring over the surface of the earth, you know, the radius of the earth. You can get the distance, the circumference that he's going, and you can time how long it takes, say, to make 10 orbits or so. And you can find out his speed this way, and it's about 270,000 miles per second, which Sean will notice is greater than the speed of light. So- - Are you telling me you didn't have a lot of dates in high school, Jim? - No, no. [laughs] - I'm not sure how this- - Well, he took them to "Superman." - They all started off like this. [everyone laughs] But anyway, [laughs] anyway, so he's going faster than the speed of light, and actually, I mentioned this once to Neil deGrasse Tyson, and he goes, "Yeah, and how's he changing direction?" [laughs] Because you need to have a force in order to be constantly changing your direction. And there, I have to go to the internet, and Bill Tippett wrote a little essay that is on there called "A Unified Theory of Superman's Powers" that explains how Superman does all these amazing things, and basically, he postulates, in my book "The Physics of Superheroes," I grant each character a one-time miracle exemption from the laws of nature and say, "Well, if you were super strong or stretch like a rubber band, you know, could you do these things that you see in the comics?" And Tippett's miracle exemption for Superman is that he can change the inertia of anything he touches. He can basically change the mass. So you could be bulletproof if you can make the bullets have the inertia of a dust mite. You can lift a car overhead if you can make its inertia be that of a pillow. You can be immovable if you increase your inertia to some dramatic amount. Now I will have to make a friendly amendment to Bill Tippett's theory, the theory 0.2, [laughs] 2.0. Let's assume that he can also change the inertia of things that he's not in direct contact with, and so now, Sean, you'll appreciate this. If he can change the mass energy density about him, he can change the curvature of space time, right? - I do appreciate that, yeah. - Okay. So he's creating a trough around the earth that's making him go faster and faster. So if he's going faster and faster, you know that from his point of view, he's stationary. The earth is going around him at 270,000 miles per second, right, changing your perspective, which, you know, what's the center, what's moving or not is relative, and then he basically turns himself into a Tipler cylinder. So Tipler said that if you had something like the mass of three black holes rotating near the speed of light that you would drag the frame of space time with you, and that frame dragging is a real thing. It was experimentally verified Gravity Probe B, and Tipler suggested that if you go opposite to the direction of rotation, you would go in a backwards time curve and reverse. So basically, he's making himself a Tipler cylinder that is changing that he, and going reverse to that direction. He is going backwards a few minutes long enough to reverse some of the damage, maybe not all [laughs] enough to save Lois. Then he has to go the other way so that he can get things time to go normal. And this all ties into a story that I was told by the son of the editor of "Superman" comics, that Mort Weisinger was the editor of "Superman" comics in the 1950s, and he got a letter to the editor of "Superman" comics from some physics students at MIT, and they complained that, in one story, Superman was going faster than the speed of light, and this is in contradiction to Einstein's theory, and what do you say to that? And Mort Weisinger's reply was, "Einstein is only a theory, Superman is fact." [everyone laughs] So here we've got Einstein's theory and Superman combining to save Lois Lane. So with that I'll have my- - So you're saying there's a chance. [everyone laughs] - That's right. That's right. - Is that like a sort of after the fact, "You know what, okay, I made it work," or do you think- - Oh no, no, no, no. It's totally after the fact. - 100%. - The thing is, at the time in the movie, the thing was you go, "Oh yeah. He's always going like in these loops faster than the speed of light and creating a rip in the space time continuum," which, you know, Sean will agree doesn't mean anything. Right? It sounds cool, but it doesn't mean anything. But he's always doing that, you know? They always said, "Well, if you can go fast enough, you can go faster than the speed of sound. There's a sound barrier." Obviously, there's a time barrier [laughs] that you can go fast enough and you can exceed that. That was the physics of the 1950s comic books that they were basing this off of. This is basically a sneaky way to talk about general relativity. [everyone laughs] - In the context of a movie, yeah. - No, exactly. It's like, you know, come for the Superman, [laughs] and I don't notice that I'm sneakily getting you to eat your spinach at the same time, so. - So I wanna- - This was not at the time, I'm sure. [laughs] - One of the things that we didn't cover in our guide was time loops, and it was basically 'cause we were trying to narrow down the list. We didn't make an exhaustive list. We pitched 20 films that we thought were very different from each other and highlighted different aspects of time travel. There's just too many time loop movies starting with like "Groundhog Day," "Run Lola Run," "Edge of Tomorrow," those sorts of things. So I wanna talk a little bit about that particular sub genre, and, you know, Sean, maybe you can talk a little bit about the physics of that. I assume, you know, closed time-like curves are the closest thing, and then we can talk about what our favorite examples are, you know, in film. - Yeah, time loop movies are, believe it or not, worse than regular time travel movies in terms of making sense and obeying the laws of physics, but, you know, the breakthrough here, my philosophy of being a science consultant on movies or trying to help people make movies or write stories is you can't just say, "The laws of physics don't allow that." The screenplay or the plot is the data, right? Like it happened. You have to tell a story. You have to invent the theory afterward. Jim's agreeing with me. - Sean, Sean, you absolutely know they couldn't put it in a movie if it wasn't true. - There you go. - So in a time loop, - Thank you. - the thing that is very, very hard to make sense of is somebody is experiencing the linear passage of time, right? Bill Murray has a memory of what he was doing yesterday, and the rest of the world doesn't. The rest of the world resets, okay? There's nothing in real honest to goodness physics that makes that happen. This is just magic. That's okay, but you know what? If you watch "Groundhog Day" or "Run Lola Run," I have less problem with it because, once you have that one buy, once you say, "Okay, that's what happens," everything seems perfectly logical. In "Back to the Future," I have no problem at all with the idea that a DeLorean going very fast can travel to the past. Spoiler alert, it's not actually true in according to the real laws of physics as we know them, but if you give that, then you can ask, "What would the consequences be?" My problems with "Back to the Future" are all that the consequences also make no sense, but "Groundhog Day," Run Lola Run," "Edge of Tomorrow," yeah, love 'em, great, no science whatsoever. [Sean and Jennifer laugh] - Actually, in "Run Lola Run" though, I don't think she has memory of what she had done in the past. - I don't remember enough, yeah. - I think she's just like trying different things, you know, as a reset and because there's like a slight change in her path or something. So she gets to a certain intersection a little bit earlier or later than she did before that the history then unfolds in a different way. For all of these, with "Groundhog Day," too, the time loops stop when they get the right answer. - Love. - Right? Yes. - Love is the right answer. - Love, it's the fifth force, as you know. [Ed speaks indistinctly] - Well, you know, you guys both bring up something that I think is in the context of writing, there's this rule. It's not a rule, but it seems, what do you guys call something that there's not a stated rule, but it kind of, when you look at, it's- - More like a guideline. [laughs] - Yeah, I mean, it's an internal guideline, I guess. It's this notion of one buy. You said, "You get one buy," right? Like one buy. There's a feeling in writing movies with the notion of coincidence, for instance. You're allowed one coincidence to your central character that can be positive like a gift or some weird thing that happens, but that has to be early. Later in your story, a coincidence that helps your protagonist will do the thing that Jim was talking about. It'll just blow you out of the movie, which is really interesting. You can have as many coincidences. Well, you can up to a point later in the movie if they're bad for your central character, like suddenly the wrong person shows up. You know, the one person who knew that Jim is not actually Jim, you know, from Minnesota. He's actually, you know, in the witness protection program. Exactly, he recognizes him from before he had his latex mask put on or whatever. That guy happens to have been on layover at the airport and, you know, sees Jim and suddenly goes, "You're in trouble." You can do those, but you can't do a positive. You can't have a coincidence to help your protagonist moving forward. Now I'm speaking, and it's kind of a generality that doesn't apply all the time because guess what? You can break any rule if you do it right, if you do it well, you know? And that's why like if with comedies, if it's funny enough, nobody cares how many rules you break, you know? But you can often like give someone one strange miracle occurs to them. You know, they suddenly realize, you know, they can shoot rays out of their hand, you know, but they can't go they suddenly realize they can shoot rays out of their hand and then later they realize they can also see through buildings, and then they realize they can, you know, they can have one, anyway, that's it. - There is actually an informal guideline very much like that in the actual progress of theoretical physics, you know, when you have some phenomenon like, oh, the galaxy is rotating too quickly. So you wanna invent a new theory to help explain that, and the way it's usually phrased is you're allowed to invoke the tooth fairy once. [laughs] So you can change the law of gravity. You can change Einstein's law of gravity to make the galaxies do what they do, or you can say they're these invisible particles called dark matter, but gravity is what it is, and people will take you very, very seriously and test your theory and write papers about it. But if you say, "I'm gonna do both, I'm gonna like have new invisible particles and change the law of gravity," no one pays attention to you. - At least the narrative, you need certain touch points of reality, and if you move more than one, you've suddenly lost any sense of orientation, you know? - You know, one time, they got away with it with what you're suggesting, Sean, with neutrinos, right? They could not account for missing energy in beta decay, and so Pauli said, "Oh, there's this ghost particle that has the property that you can't detect it, but it's carrying off the missing energy," and it turns out to be like the second most common particle in the universe after photons 'cause they eventually figured out how to detect. So yeah, sometimes you can get away with it. Yeah, I think actually, Ed, when you have the coincidence at the very end that saves your character, then the phrase that popped in my mind was like deus ex machina. - Yeah, for sure. - I'm not sure how it's pronounced. - Yeah, it's unearned. - I think it's deus ex machina. - Deus. - Deus ex machina. - So it's that. It's like, oh, you know, you couldn't figure out- - Yeah, an act of God comes in and basically fixes things for you, and it's like- - Or as Deadpool says at various points in his movies, "Now that's just lazy writing." [everyone laughs] - Yeah, which you can get away with only, you gotta be careful with that, but if you can get away with that, like we know our script is lame, so let's just have a character call attention to it. - Putting the lampshade on it, right. - Yeah, hang on. Yeah. There is a rule in writing. If you can't fix it, feature it, you know, which is if there's a, or, you know, like you have a real issue. You have a real thing that doesn't make sense, hang a lantern on it. Don't try to hide it. - Jennifer and I have the saying that without physics, there is no drama because if you can constantly just make up the laws of the game, and very, very broadly construed, not just literally the laws of physics but the laws of, you know, logic and narrative, whenever, then, you know, the audience is not feeling any sense of jeopardy, right? It's only when there are constraints, only when there are rules, things you can't do that the story becomes interesting because then you have to figure out how to get where you wanna go within what you can do. - I'll take that a step further. Without those rules, you don't have a story at all. Rules are freeing. The more rules, the specific rules, the more you know the rules, the freer you are to create. A lot of people think that the blank page or the white snow or whatever you wanna call it, you know, is the place to be, but, in fact, it's the opposite. It's a lot easier to solve a script problem when you have very limited constraints. That's why a lot of the best ideas come when you are in the last few days of shooting and you have a big story hole, or you're doing a re-shoot and you only have like a day or two days, but you only have two of your four actors. You've got a quarter of your location 'cause they've already undone most of it, you know, and you have to shoot really quickly, and you can't have the child actor, and so you're suddenly forced to construct something with a series of rules. They're often the most creative. That scene that you're talking about in "Bill & Ted," we had a lot of rules, quote unquote, "against" us, which caused us to have to think about something outside the box. You need those rules, and like to me, if you were asking me, you know, in constructing any science fiction, if you had to say what one rule, you know, I would say, "It's about the human beings, period." You know, and if it's not emotionally accurate, it doesn't matter. There's a phrase I call this. I don't know if it's an actual phrase, but, you know, a lot of times, people do a lot of research into the science of the science fiction thing that they're trying to write, and I call it sci-fi porn. It's like they get so enamored with this science fiction that they've just learned or the science that they've just learned that they want to show it all, and it becomes about that, and nobody cares at the end of the day if your human beings aren't working. I would argue that two of those time loop movies are the comedies "Groundhog Day" and "Palm Springs," another one, which I thought, "There's no way 'Palm Springs' will work." You can't top "Groundhog Day," which I thought was a beautiful, almost perfect film, and "Palm Springs" was, I thought, also really brilliant to me because it was emotionally true and funny, and it makes it work, yeah. - It does. - [Jim] Jennifer, should I get a Clifford on the phone? - No, that's okay. [laughs] - [Ed] Was it someone that was gonna disagree? - I am gonna- - No, no. He was the science consultant for "Palm Springs." - Well, tell him he did a great job. - I absolutely loved that movie, too. So I wanna take a couple of questions 'cause we do have some, and the first one kind of ties into what Ed was just saying about, you know, how it has to matter. There has to be an emotional core because one of the movies that we included was "Primer." It's a time travel movie. - Very low budget, extremely low budget movie, yep. - Extremely low budget, and, you know, it's got a kind of thorny take on time travel, and Sean and I did not give it particularly high scores. It's, A, boring. You know, there's just not a lot of emotional connection there, and it strikes me as the writers just fell a little bit too in love with the physics and with being clever, and they were just way too clever for their own good, and they ended up not making any logical sense. But you can go online, and there are people who actually think it's the most brilliant, most physics accurate movie ever, and we disagree, and I open up a floor for discussion on that point. [laughs] - No, I was actually disappointed when I heard so much about "Primer," and when I finally saw it, it was like, "Wow." It was almost like homework watching it to the end, you know, because I wasn't engaged. Along the lines of what you were saying, Ed, you know, there's this David Mamet about like every scene. It's like, "Who wants what? Why can't they have it? Why do I give a crap?" To some extent, it's actually also- - I love that nobody swears on this podcast. I don't know why that is, but I'm gonna just go with it. - Just erring on the side of not getting like bleeped. [Jennifer laughs] - Got it. - And actually, Sean, I mean, I tell my students the same philosophy for giving a talk or writing a paper. It's like, what is the problem? Why hasn't it been solved? You know, what am I doing about it? Why does anyone care? You know, why do you give a crap? But that's exactly right is that there has to be something to make me engaged, you know, in the movie or even just even as you're relating a piece of science to. - Yeah, and I think my point is that, done correctly, science, physics, whatever helps with that sort of emotional journey. I mean, my go-to example here, which is a little bit unfair, it's not really time travel, is JJ Abrams' reboot of "Star Trek" where, in the very first one, there's this ball of red matter, and red matter is very bad. And look, I don't want a lecture on the physics of red matter, but I would like to know why it's bad. Like if I touch it, is it bad? If it leaks out, is it? Like I would like to know a little bit about the rules of the game so that I know what I can and cannot do. That helps. That increases to me the narrative tension. - Right, I can't speak to red matter or to that film 'cause I don't think I saw it, but I did just remember something about "Groundhog Day," which is originally in the film, there was a long explanation for why this happens to Bill Murray's character. You'll notice that there is no explanation. It just happens. The film did not work apparently. The audiences were not caring for it, and that person, ironically, the person who was in that meeting with me with Tommy Lee Jones who was, the only time I ever saw him on "Men in Black," he had nothing to do with it except 'cause to be in the room with Tommy Lee Jones and then agree with everything he said. That person who is not known as being a particularly bright individual in general suggested, "What if we just don't know the answer? What if we don't?" And that made the movie work. So to that, I owe that to that person's credit. I had no idea why red matter wasn't explained, none, but sometimes not explaining it is better than trying to explain it. It's almost like if you open something up like trying to give it any logic because then it just creates a series of questions and, yeah. - But I think this is an important distinction because, like you say, in "Groundhog Day," you don't know why it happened, but you very quickly learn the rules. - Right, right, the rules are very clear, yeah. - Everything happens, and that was my problem with red matter. Again, I don't care what it is. I wanna know what it does. I wanna know like how we're allowed to treat it, and then I'm gonna be worried when people are about to do the wrong thing with it. - Right, but you don't care like where did it come from. - Don't care. - Like who originated red matter? That's not important, but it's important about why do I give, [laughs] right. - Why do I give a crap? [laughs] You're just dying to swear, aren't you, Jim? - You kiss Sean with that mouth? - Holding it back. - I know, Jesus. That's why she's also seeing me on the side, yeah. [everyone laughs] She likes the clean, you know, honest, honest to goodness, clean-cut young man like myself, yeah. - Okay, so- - For the future. - We have another question. This is from Ryan, who's a big fan of the show "Terra Nova." He says, "Are multiverse time travel movies and shows the most realistic in terms of hard sci-fi?" And Sean, this gets back to your opening comments about how all bets are off once you have alternate timelines in a multiverse. So maybe can start with you on that. - Look, the idea that there are multiple universes is a very realistic one scientifically. We obviously don't know if it's true or not. I think it probably is. I'm an advocate of what's called the many worlds. - [Ed] In this universe, we don't know. - We don't know. The many world's interpretation of quantum mechanics, which gives you very, very specific rules about when these other universes appear and what they're like. Now, of course, cinematically, we would therefore like to be able to time travel to these other universes. There's nothing in the known laws of physics that lets you do that. There's not even, you know, the equivalent of Kip Thorne and his friends back in the early 90s showed us how to build a time machine using wormholes, and they were obeying the laws of physics as they currently understood them. Still very hypothetical, but they were doing physics. No one has done that equivalent for multiple universes and multiple timelines. We don't have a consistent, coherent theory that says, "If I could go back into the past and there were also multiple universes, I could go into one of those multiple other universes and change it," so that's up in the air. That's waiting for someone who's in the audience, a smart young person, to write that physics paper. - Is that Hugh Everett? Was that the- - Hugh Everett, yeah, yeah. - Hugh Everett III, yep. - You know who his son is, right? - Mark Everett. - Yes. - I know who, yeah. - No, no, yeah. - From the Eels. Yeah, from Eels, the band. Did you see "In Two" and "Across the Spiderverse"? Did you see those? - Oh yeah, sure. - Yes. Loved them. - I thought they were amazing films, and they obviously used the multiverse in a certain way. Again, nobody's trying to explain how it happens. - Which is perfectly fine. So yeah, so I think even without the full physics paper, I think that it would be very interesting to think harder about what the rules might be. So if I could travel into the past but into another universe, do I meet the version of myself that is already in that universe, or like does everyone get shifted over one universe? I don't know what the rules are. - I mean, if it's infinite, then there's a universe that's just Sean Carrolls. - Not true. It's not- - Yes, it is, Sean. It is true. - It's not true! - Next question. - Who is the professor of natural philosophy here? - It's true. [everyone laughs] That was, what's the guy's name who did "Palm Springs"? - Clifford Johnson. - Clifford. - No, no, that- - That was Clifford Johnson. - Yeah, right, yeah. - He was the science guy. - The fact that there's an infinite number of things doesn't mean that everything happens in them. The fact that there's an infinite number of even numbers and none of them is an odd number. There can be an infinite number of universes and still not every possible universe happens. - [Ed] But how do you know that? - I'm just talking about the space of possibilities. I don't know what is real or not. Maybe there is a version of every conceivable universe, but that's not what is predicted by our current laws of physics. I'm here to lay that here. - Well, but Sean, Sean, there's different- - I have the whiteboard right here. Don't make me use it. - No, there's different, yeah, right. - I can write a bunch of bull - I have the [speaks indistinctly]. - S-H-blank-T - Okay? So. - on my board and play science. I have one behind me as well. - I have a cosmic being here. - So before we get the equations going, I have another question. [everyone laughs] - [Ed] Oh, right, that. Oh, we're back. I forgot where we were for a moment. - Yeah, so there's another- - Someone's watching this. What? - There are people watching this. - Sorry. We apologize. - There's a fellow Jennifer who asks, "What do you think about the kind of time travel in quantum belief where only the consciousness is able to travel?" And we actually talked about that a little bit in our guide with regard to "Hot Tub Time Machine," which is probably a far better movie than it ever had any right to be. I really love that movie, but in that one, their consciousness basically travels back in time. So what do you - Yeah, what was - think about that? - the first movie to do that? Was "Peggy Sue Got Married" did that? Or there might've been. - I think so. "Peggy Sue Got Married" did that as well. - Even earlier ones, but yeah, that's just completely crazy pants. That cannot happen. Don't think that there is some version of respectable laws of physics that would explain that. That's your buy that you have to just buy, and I don't even know if it would really make sense. Where did your memories come from if suddenly, your consciousness is in your younger self again? You would lose sleep if you tried to make too much sense of that stuff. - Right. Anyone else have thoughts before we move on? One second. I'm seeing blank looks. - No, I don't think Sean knows anything about what he's talking about about any of this. - It's a matter of speaking with an authoritative tone of voice. It's not a matter of knowing anything. - But you do do that. That's true. - Yeah, exactly. - Knows how to do that. - Fake it till you don't make it, yes. - All right, so Abjit asks, he goes, "Let me bring the most profitable one for a query. What are the thoughts on 'Avengers: Endgame,' especially the fact that Cap stayed behind, and what inconsistencies it should have brought?" - [Sean] You know, I think that I was- - I know that you actually were involved with "Avengers." - I was so I gotta I gotta talk first here. You know, my biggest contribution to popular culture is when Paul Rudd in "Avengers: Endgame" says, "You're telling me 'Back to the Future' is just bullshit?" That line came from me acting as a science consultant for the movie because they were thinking early on about, you know, they needed time travel. How was it gonna work? And everyone's seen "Back to the Future," and we rated it as a great movie in our "Ars Technica" article, but I had to point out that the physics or the logic of it made no sense. And in particular, the scene where Michael J. Fox is there back in the 50s, and here in the present day in the 80s, there's a photograph of the family that starts changing. Like people from the family start disappearing because he's changing the past, and the question that will lead you to realize that this is nonsense is why did it start changing then in the 1980s? Like why was it just never there in the first place if he changed the past in the 1950s? So I did a pretty good job, I think, of convincing the Russo brothers, et cetera, that they should try to obey the rule that, if you travel to the past, you can do things, you interact with it, but you can't do something that's inconsistent with what you already know about the present. And I would say at the 95% level, they did that in "Endgame," but I think, following Ed's philosophy here, if they could get a good joke in there, if Captain America could fight himself and make wise cracks about his A, no, I can say it. Anyone else is afraid. That was America's ass in "Avengers: Endgame," - Yes, he did it. He did it! - And that was- - He said it! - That was worth that little bit - Across the A-S-S injury. - of temporal inconsistency. It was worth violating the laws of logic to have that joke in there, and I totally agree with that artistic choice. [Jennifer and Jim laugh] - So we also have a question, not really a question, but someone who's asking about the time travel in "Looper," and that was another one on our list that did not get particularly high marks, particularly because, I mean, look, it's visually great. You see this one guy who is older, and they've got his younger self, and they're slowly cutting off like parts of his body, and you're seeing him lose those parts of his older self losing parts of those body in real time and as it happens. So that really bothered Sean in a big, big way, and so it's appropriate that Sean will tell us why that bothered him. [laughs] - Well, I don't know if Ed has ever had Rian Johnson on his podcast or not, but my- - No, no, I'd love to. If you know him, hook me up please. - I don't, but let's just, you know, imagine it to be true, right? You know, that "Looper" did its own version of the disappearing people in the photograph in "Back to the Future" with the disappearing fingers that the guy had, and so this poor guy. Like he's trying to escape, and his fingers are disappearing because his younger self is being tortured and his fingers are being chopped off. Now that obviously makes no sense because he thinks he had fingers five minutes ago. Like where did that moment of finger disappearing come from? But it was so egregious, and if you look at like the rest of the movie, it makes all of the classic time travel illogical blunders. Like my secret theory is that Rian Johnson was doing it all on purpose, that he knew exactly what he was doing, and he was having fun with it. So I don't give it quite as much of a hard time as I give "Back to the Future." - You will buy stuff in a film if it's funny, if it feels emotionally true, and if it fits into the physics of your own film, the film that you are creating, and that means that the tone and mood of the film envelope the concept of the film in a way, and that's usually carried on the shoulders of your central characters and or the filmic style, for instance, you know, "John Wick," let's say, which is a, you know, very critically well received, and some of the "John Wick" films are quite well made is if it was shot differently, if it had a different tone, it would be one of the ugliest things you've ever seen in your life, but because of its tone, you sort of go along, I guess, with it. So, you know, it becomes a qualitative assessment as opposed to a, you know, there should be, you know, yeah, instead of a quantitative assessment. - Well, if you've seen "Looper," there is a very funny famous scene where Bruce Willis, who is the older version of Joseph Gordon-Levitt's character, and they're talking to each other in a diner, and Bruce Willis is trying to explain how this time travel thing works, and he says, "You don't wanna hear about that. I'd be like, drawing diagrams, and there'd be straws on the table and the whole bit," and that's it. But apparently they filmed the longer version where he was using straws on the table to explain all the time travel nonsense, and then they cut it, and it goes exactly with what Ed said. It was better for the movie. - Always. Yeah, always. It's always the case. And I can't speak for other writers. I guess I'll just speak for myself here. I often think that we know we're lying. You know, like Sean is a film consultant, you probably know this, we know we're lying. And you know how when people lie, they overexplain? I think there's that tendency in film - I like that - to kind of overexplain, and then you realize, "Oh no, just pull it back. Just be confident and pull it back." - That's really good. That's a good point. The part that took me out of the movie in "Looper" was the notion that Joseph Gordon-Levitt would age into Bruce Willis. [everyone laughs] No, I'm sorry. Fantasy. - Suspending disbelief here. - But by the time- - It's sad enough having Bruce Willis age into Bruce Willis. That's hard to watch. - Still, you haven't watched "Moonlighting" recently, Jim. It's not that much of a- - Hey, no, no, no. I did. No, sorry. Okay. - Ed, maybe you haven't thought about this. How much does it help to literally film the explanatory scene and then cut it? Like does that help you out? - I'll tell you. Well, I mean, you know, that can be an incredible waste of time and money, but you never know. You always think you need it. It helps to sometimes write all that stuff, but it takes a certain amount of confidence to then be able to go, "Trust me, people are only gonna need this much." [sighs] If I look back at the amount of reshoots, the various things I've done that have had, I mean, I've been doing this so long, and I've had so many things where you go in and you're like, "Okay, what I thought would work doesn't. What I thought we need less of we need more of. What I thought we need more of we need less of." So when I think about when we've added and when we've cut, I've averaged being just on target, which means half the time, I add too much, and half the time, too little. The reshoots usually are early to explain things you didn't think needed explanation, massive edits because you way over explain things that are very obvious when somebody just sees it. We often forget how cutting from one thing to a second thing creates meaning in and of itself. You know, Sean says, "It's funny. I heard there was like nuclear tests going on in our neighborhood," and then like his lights flicker, and then Sean's gone. You know, there could have been a whole series of scenes where you're showing Sean like being engulfed in a nuclear flame and all that, but you basically understand what you- - You figure it out. - What's happening by the cut. The other thing is toward the end when you think people will be satisfied with certain things and they need it bigger and more powerful and whatnot, but usually, people know. Usually people don't have certain pieces of factual information that they need, and they often do have way more emotional information than you think they need, I have found with my stuff. Yeah. Did I answer your question, Sean? I'm not sure. - Very much, yeah. No, it's, you know, better you than me is the lesson that I'm learning here. [everyone laughs] - So we're winding down on our time here, but I wanna like close with us each going around and talking about our favorite time travel movie. I mean, in our guide, Sean and I ended up picking "12 Monkeys" as being a movie that kind of came as close as perfection as possible so far marrying like time travel logic with just being a really good story with like emotional stakes and resonances and great characters. So it like really worked both as entertainment and as science and logic. So I wanna kind of open the floor up. What are some of your favorite time travel or time loop movies that you and why? - I can go first or last 'cause I helped write the list. So I have plenty of examples in my brain right now, but- - I'd love to hear like some of what they are 'cause I didn't come prepared with a list. The first two that come to mind I know, but I wanna hear what some other ones are. - Well, I'll- - Well, I'll mention two for different reasons. Like, one is "Interstellar." "Interstellar," you know, Jennifer and I are good friends with Kip Thorne, who was the executive producer and helped originate the idea of the movie. And that movie was originally supposed to be directed by Steven Spielberg, and then various Hollywood machinations happened, and it ended up being directed by Christopher Nolan. And when Spielberg was involved, he entirely bought the conceit of getting all the physics literally right, like not just within the movie physics but compatible with physics as we understand it in the world 100%. Like maybe you are speculating, but you're speculating in ways that are compatible with what we know. So maybe wormholes can exist, but they would obey the laws of physics, and apparently when Christopher Nolan came in, he was less 100% devoted to that. So Kip Thorne or Jonathan Nolan, who was credited as a screenwriter, if you ask them about the last 15 minutes of the movie, they'll just roll their eyes and go, "Yeah, don't ask us about that. We have no idea what's going on with the library and, you know, the extra dimensions and whatever." But at least they tried, and, you know, I will absolutely, no movie, even "12 Monkeys" or whatever where they try to have time travel in a logically consistent way, almost no movie actually tries to make it compatible with the laws of physics as we know it, general relativity, et cetera. So kudos to "Interstellar" for that. The other is, of course, "Time Crimes," which is a fun French, not fun, it's actually very gruesome and dark, but it's a French movie about time travel, and it's 100% consistent. And there's one character who, you know, goes through multiple time loops, interacts with himself, and it all makes sense, and the cleverness is all in this thing that you saw from the point of view of the character when they were younger. Now you're seeing it from the point of view of the character a little bit older, and it's completely compatible but still surprising, and there's a genius to that that is really wonderful. So what I like about that is that not only is it consistent time travel, but it's used in the narrative. It's not just showing off that they can be consistent. The dramatic tension comes from the use of time travel in a clever way. - What do you think of "Time Bandits"? - Oh that's interesting. That's one that we actually omitted from our list that everybody kind of, we got a lot of like crap for that because people were like, "How could you like skip 'Time Bandits'? I says, "Because we had 'Bill & Ted,' and it was like a better example." [Ed and Jennifer laugh] There really is- - Well, in fact, you know, if you watch- - Thank you. - If you rewatch "Time Bandits," which Jennifer and I did, because we are devoted conscientious researchers- - Oh, the sacrifices you make, yes. - That we make so many sacrifices. - [laughs] I know. - But what you realize is, you know, Terry Gilliam at his best, you start with some time travel, but then the fact that it's time travel kind of dissolves, kind of dissipates and disappears, and it's just pure fantasy by the end, and the time travel becomes kind of not the point anymore. So that's why we did not include it in our list. - While you were talking, Sean, one thing that occurred to me that's not a time travel movie from the point of view of the people in the movie but makes the audience go through some, in essence, time travel is another Christopher Nolan movie, "Memento." - Love it. Yeah. - Right, but then because you're watching the movie basically backwards, - Half backwards, - But you see- - half forwards. - But you see- - It's even better. - But there's also the forwards part where the black and white where the guy's giving the narration of what was going on, and at the end, like it comes together, and you realize what's going on, but you are experiencing it backwards. - Well, this is a little epiphany that I eventually had when I tried to figure out following my own advice that one should treat the screenplay of the movie as data, and you can't just say, "No, that can't happen." You should say, "As a good scientist, what do I have to do intellectually to make sense of what is happening here?" And in the case of even "Back to the Future," or "Peggy Sue Got Married" or "Hot Tub Time Machine," right? Like none of these make any sense if you're at the superficial level. Can you make sense of them? Why is it that people can watch "Back to the Future" and just love it and not be annoyed at the fact that it makes no sense? And the answer is exactly because there's another idea of time which is time as experienced by the people watching the movie, right? And the characters don't experience that time. So the character in "Looper" whose fingers are being cut off, honestly it makes no sense to him that his fingers are suddenly disappearing. There's just no way to make sense of that, but to the audience makes perfect sense. 'cause three seconds ago, we saw his younger self get his fingers being chopped off, right? So if you want to make these things make sense, it's some kind of meta time, narrative time as experienced by the audience that you have to include in your ontology, as we philosophers say. - I think yes, what the audience is experiencing, and also, you know, my wife and I were watching several different standup comedy specials by comedians who for one reason or another had a special after they'd been, it's not canceled, but kind of on the outs, and it was very interesting to watch 'cause we were going, "Wow, what's our emotional response to this?" And what we found is though the acts that each of these various people had perpetrated were kind of awful, we felt more empathy for the ones who were funnier at the end of their special. And I thought that was interesting as a craftsperson, you know, in that trade because she's a writer, too. She's the best writer I've known in my life, and she's amazing, but we were both going, "Well, that's really interesting," 'cause here we are. We're in 55 minutes, let's say, difference between before the special and after the special, and yet we have a different emotional feeling about this person. They each committed various things, you know, for obvious reasons I'm not talking about, and I found that fascinating, which is really when you make your art, how good is it? I think art is, well, it's many things. It's not an intellectual communication. I think it's an emotional communication, and I think that, you know, a film watching experience is an empathic. You project onto a character and you sort of, it's an empathic experience. So how much room do you make for that, the empathetic relationship and experience? You know, that's the determinant of whether you buy in or not. Jim, you didn't get to say what your favorites are, and then I know we have to end. - Oh no, no, actually, I now have just like forgotten what I was going to say - That's okay. - the "Memento" thing. Actually, I'd rather go with "Memento." It's just because - A good choice. that it made me go on a time travel. - And Ed, what about you? What is your- - "Groundhog Day," "Palm Springs." - That's what I was gonna say, but yeah. - Oh sure. - I think they're great movies. - Yeah, well, my consciousness went into Ed's body. [everyone laughs] - That's my goal was to get Jim's consciousness, so- - Sucker! - [laughs] Oh Jim, what have I done? - I know Jim has to leave in about five minutes, so this is actually a good time to end it, and guys, thank you so much for doing this. This has been a lot of fun, and we could probably continue talking for another 30 minutes, but you know, always leave 'em wanting more. - There you go. - Thank you for very much - So we're gonna end it there - for having me. - and say goodbye to everybody who will join and goodbye to you guys, and thank you so much. I think this has been a really fun discussion. - Yep. Absolutely. - Bye bye - Thank much very much. - out there in lick land. - Thank you very much. [upbeat electronic music]