The Metaphysics of Interstellar A Conversation with Kip Thorne and Christopher Nolan. BY THE TIME Christopher Nolan signed up to direct Interstellar and started rewriting its script, astrophysicist Kip Thorne had been working with Nolan’s brother, Jonathan (who goes by Jonah), on getting his ideas onto film for years. When Chris and Thorne met, they quickly found common ground: Thorne wanted science in the story, and Nolan wanted the story to emerge from science. So in Interstellar, time dilation—the passing of time at different rates for different observers—became an emotional obstacle between a father and his daughter. Quantum gravity, the reconciliation of relativity and quantum mechanics, became the plot’s central mystery. The visual effects team even collaborated with Thorne to make sure their depictions of a black hole were accurate as well as elegant. But to make it all work, Nolan, who never really understood algebra, had to internalize the science to which Thorne has dedicated his life. That the two men ended up liking each other was just a bonus. Here, Nolan and Thorne describe their work together, what they think they’ve achieved, and how they found détente when the story sought to break the rules of physics. When it comes to moving through time, Thorne says, “Chris came up with his own set of rules that fit into what we physicists think we know.” WIRED: How’d you guys get together? THORNE: When Chris signed on to direct and rewrite the screenplay, he called me and said he wanted to talk. NOLAN: I was really hoping to just get broad-strokes sign-off on some things I wanted to do with time and gravity. My brother, Jonah, had worked on the screenplay for years before I came on the project and had a lot of meetings with Kip. So I called Jonah and said, “So what’s up with Kip Thorne? Is he going to tell me what I can’t do?” And Jonah told me, “No, it’s really productive.” And it was true. THORNE: I had worked closely with Jonah for several years, and I knew Chris’ work. I particularly enjoyed Memento, and Inception came out while I was working with Jonah. I loved it. WIRED: Chris, Inception works without “real” science. Why did you need physics for Interstellar? NOLAN: Well, it will sound strange, but to me Inception had a lot of science in it: A rigid set of rules, mathematical and geometrical in their nature, define that script. That took a very long time to work out. They’re not real science, but they have that quality. You always have to cheat in cinematic narrative, but you try to do it as little as possible and in a way that doesn’t violate the pact with the audience. In Inception, the geometry’s pretty solid. WIRED: But without giving away too much, key Interstellar plot points—the main quest and the climactic scene—rely on hardcore science. THORNE: In our first conversation, we discussed moving forward and backward in time and the fact that physicists don’t yet know for sure what the laws of physics allow and forbid. So Chris came up with his own rule set, and I came up with a way to fit it into what we physicists do think we know. NOLAN: Yeah, that was my understanding of what you and Jonah had been pushing. THORNE: But we had not laid out rules. NOLAN: No, you’d been exploring and exploring it, and part of that first meeting was me letting you know there’s a new sheriff in town. Jonah loves ideas. He’s fascinated by the science. Part of my job was to find a focus. THORNE: But you had somehow extracted a key piece of physics that is not generally known, the idea that gravity can reach across multiple dimensions while none of the other physical fields can. WIRED: Wait—Kip, you’ve been working on gravitational waves for decades, and the Nolans just intuited them? NOLAN: No, we didn’t intuit it. What you do as a writer, working with somebody like Kip, is you—well, I’ll give you a different example. In Kip’s writing I found the question of whether a singularity, the heart of a black hole, is always hidden, or whether you can have what’s called a naked singularity. If we knew what was going on in there we would understand a lot more about how to reconcile quantum physics with larger physics. I grabbed that like a magpie. It’s one of the greatest mysteries in the universe. The gravity thing, it wasn’t a question of us intuiting it. It was all the discussions that Jonah had with Kip. WIRED: Kip, were there places where you said, “Whoa, settle down, you can’t do that. That won’t work”? THORNE: Only once. NOLAN: Yeah, there was one. ONE OF THE problems with a story that depends on dimensions beyond space and time is that it has to be complex but not complicated. An audience has to pick up concepts that even ace astrophysicists have trouble metabolizing. Like the proverbial observer in the theory of relativity, your perspective affects what you perceive. That’s what happened to Kip Thorne and Christopher Nolan. As they hashed out the science of Interstellar, the scientist and the storyteller looked at the same truths and—at least for a while—saw very different things. Here’s what their trip down the rabbit hole felt like. WIRED: Chris, where did Kip have to rein you in? NOLAN: There was one thing. I was determined to have a character travel faster than the speed of light. WIRED: Uh-oh. NOLAN: I wanted to break the light barrier, as I called it. And Kip wasn’t having any of that. That went on for a couple of weeks. THORNE: I gave him a document where I laid out the reasons it couldn’t work.1 We had a couple of conversations, and he backed down. NOLAN: We had more than a couple of conversations. What he’s not telling you is, I finally managed to get my head around relativity. I don’t mean a full understanding of it. I mean a glimpse of a feeling, you know? Like when you’re trying to play an instrument and you happen to hit the right chord? So I said, “You know what? I agree. Nothing can travel faster than the speed of light.” And he goes, “Yeah, well, in localized regions it can’t,” or something. And I’m like, wait a second! Every rabbit hole has another rabbit hole at the bottom of it, and another rabbit hole. WIRED: He incepted you with relativity. NOLAN: Oh, very much. I lost it pretty rapidly afterward. Jonah says that through working with Kip, he finally grasped relativity for a couple of weeks, and then the writers’ strike happened and he had to stop writing, and it was gone. I know exactly what he means. It’s like a little window opening up. That’s why the relationship between storytelling and the scientific method fascinates me. It wasn’t really about an intellectual understanding. It was a feeling of grasping something. THORNE: You call it a feeling; I would call it an intuition. And this isn’t just for nonscientists. Yakov Borisovich Zel’dovich, one of the really great astrophysicists of the 20th century and a codesigner of the Russian hydrogen bomb, was a close friend of mine. He could not grasp how Hawking radiation comes out of black holes, even though he had given Stephen Hawking the key idea that underlies the concept in a conversation the three of us had. For about two years, he could not make it fit with his intuition. Then, one time I was in Moscow and I went over to his flat. He threw up his hands and said, “I understand! I give up. Hawking was right.” He finally understood it in an intuitive way. WIRED: Is that different than understanding the math? THORNE: Very different. The math was there. The math was straightforward. Well, let me take that back—those are two different things. The math was there, and the steps in the math were straightforward, but interpreting the math was not so clear. And how you use the math depends very heavily on this intuition. It’s a key part of the scientist’s arsenal, as it is for the storyteller’s arsenal. WIRED: Where else did you have problems with what Chris was doing? NOLAN: Well, time dilation. THORNE: Chris wanted a planet with time dilation unbelievably greater than I have ever seen in physics, and I just didn’t think that was possible. And he said, basically, “I gotta have it.” I went home, slept on it, did a calculation, and found that if you have a black hole that spins rapidly enough, and a planet that is very close to the last stable circular orbit, you could get the time dilation he wanted. It just amazed me. NOLAN: Our meetings never ended with definite answers. They ended with questions. As a true scientist, Kip questions everything. THORNE: Well as a true scientist I have been proved wrong so many times that I’m very humble. NOLAN: Even if the audience can’t grasp the science, my goal was to make them understand it emotionally and for it to be clear that there’s a consistency and a reality to what we’re presenting. We went back and forth about time a lot, because Kip felt that I had done certain things at the end of the film that were at odds with the rules we had talked about. Kip thought we were seeing it different ways, and the truth is we weren’t. And I kind of knew we weren’t. So we bounced it back and forth— THORNE: Yeah, a whole sequence of telephone calls. NOLAN: Well, I didn’t want it to be dismissed as wild speculation. I felt very strongly that what we had done with the climax of the movie, we’re basically taking—I hate to use the term, in a way—an artistic approach to the key visual element. We tried to construct a rigid geometrical idea, thinking about the work of Escher or any number of artists, and build a set that can demonstrate it. I came up with this idea of an array, a matrix representing all the information of a four-dimensional world in three dimensions, or a five-dimensional world in four, depending on where you count time. Eventually I was able to say to Kip, “I am not violating the rules.” THORNE: I was very happy with the whole tesseract scene—once he explained it to me. There is a fascinating scene earlier in the movie in which Brand (Anne Hathaway) says that to five-dimensional creatures, time is like mountains and valleys. You can go forward in time like climbing a mountain. You can go backward in time like going into a valley. It’s beautifully worded. But how does that fit with Chris’ rule set that says nothing can physically go backward in time? That’s where I was struggling. NOLAN: I explained that her dialogue is about analogy, it’s about perspective. It all comes back to Flatland, I think. If you’re a two-dimensional being you can’t see two dimensions. You can see one. If you’re three-dimensional you can observe that second dimension. To me, time is like that. We can’t see it. We can feel it, and we can act accordingly. But if you were a five-dimensional being looking at our world, you could observe time as a spatial dimension. THORNE: This is where we were talking past each other. To me as a physicist there is time that flows in the fifth dimension, in the bulk, and there’s time that flows in the brane2—our reality. They’re intimately connected. But this whole business that Chris was getting at was if you live in the bulk and you’re looking at how time flows in the brane, you can go forward and backward in time just fine. NOLAN: But you can’t enter the brane. And I was determined. He kept saying to me, “No, it’s fine, I’m not saying it’s impossible.” But I didn’t want to let him down. I didn’t want him to think I’d broken my rule set. THORNE: He was sure we agreed. I was sure we disagreed. NOLAN: The geometry we constructed is an honest attempt to explain to the audience that from a higher dimension our world would look very, very different. It’s an impossible task, but the attempt was tremendous fun. I wanted to be sure Kip knew we hadn’t just said, “Oh, here’s the crazy bit.” THORNE: Oh, I never had any doubt about that. I just had a doubt whether or not what you were doing fit with general relativity in five dimensions. NOLAN: In a way, the tesseract3 is an analogy. Early in the film we talk about wormholes using a sheet of paper to represent the universe, and you can fold it over. But that piece of paper is representing three dimensions. You suppress the third to make it easier to understand. WIRED: Like using two surfaces connected by a tube to diagram a wormhole, or a mass warping a sheet to represent gravity. The two-dimensional sheets stand in for three dimensions. NOLAN: Right, you’re not moving on the surface. You’re moving in the surface. You suppress one dimension to represent what you’re talking about. As Kip and I talked about the wormhole, I finally understood that it’s a four-dimensional hole in three-dimensional space. And since a three-dimensional hole in two-dimensional space would appear as a circle, a four-dimensional hole would look to us like a sphere. That’s why I put it in the film. It changed everything about my ability to understand dimensionality. WIRED: But how do you get something like that across to an audience? NOLAN: I know how to do that because of the way photographic perspective works, which is essentially two-dimensional, and the way eyes work, which is also two-dimensional. Because of diminishing perspective, because things look smaller when they’re farther away, it’s actually pretty damn simple to go, “OK, we jump into this sphere, and then there’s a smaller sphere, and then it grows and we jump into that one.” The idea that the spheres at either end of a wormhole would be the same size? Photographically that’s no problem. We filmmakers deal with that kind of thing all the time. WIRED: Fundamentally, film always flattens a three-dimensional world onto a surface. It’s not just metaphor. NOLAN: That’s why I object to the term “3-D” for stereoscopic imaging, because movies are already three-dimensional. A photograph represents three dimensions in two. And then a strip of film adds time. That’s how you take time and you represent it physically: a reel of film running through a projector. WIRED: Kip, did you interact with the actors too? THORNE: I did. A couple of weeks before he started filming in Canada, I had an email from Matthew McConaughey. He was trying to wrap his head around the role of Cooper and the science. So we met at a boutique hotel in Beverly Hills where he had holed up for the weekend to try to— NOLAN: With all his notes! THORNE: Right, he’d cleared all the furniture out except for a love seat and a coffee table, and he had 12- by 18-inch sheets of paper all over the floor and on the table with notes all over them, each one dealing with a particular science issue or, I suppose, character issue. He would pull up a sheet and ask questions and write notes. Then he’d pull up another one. It was a wonderful conversation. And then I had a phone conversation with Anne Hathaway for about an hour and a half. She began by saying, “I’m a bit of a physics geek.” NOLAN: Oh, she loves science. She was very excited to meet Kip. THORNE: She had questions like “Are there any experimental tests for quantum gravity?” Her questions, you’d expect them from a science geek who spent the last three years reading physics. Maybe. If they were really on top of their game. NOLAN: She loves science. Same with Michael Caine. He was super-excited to meet Kip. He took a picture with him. I’ve never seen Michael do that. THORNE: The first assistant director came to me and said, “Michael Caine would like to have his photograph taken with you. Is that OK?” My jaw dropped. NOLAN: The thing with good actors is, you don’t know what they’re getting from people. But there are two things going on with Kip’s involvement. One is, great actors can’t say lines that they don’t understand. Otherwise they can’t sell it. And then the other is, just by seeing somebody who has lived his life figuring these things out, they get some particular visual thing, whether it’s something you do, something you wear. It’s something that they absorb about what it’s like to devote your life to these principles. THORNE: That’s the sense I had in my conversations with McConaughey and Hathaway. They were trying to wrap their heads around the science because they had to internalize it. With Caine it was more like he wanted to understand what it felt like to be a scientist. NOLAN: I think one of the reasons is Michael doesn’t really have any science to discuss in the film. WIRED: Chris, did you ever think, “Holy crap, I have a plot that involves both a wormhole and a black hole, and it’s really going to confuse people?” NOLAN: No, I had a moment with Jonah’s draft where I went, “Holy crap, I’ve got six wormholes and five black holes.” I was like, guys, this is way too confusing. Kip had brilliant ideas using multiple black holes, but I just said, “No, we can do one black hole and we can do one wormhole, and that’s pushing it.” THORNE: At one point in the story, a spacecraft that’s going at a quarter the speed of light has to slow down. I said the only way to do it is by a slingshot around a black hole. Chris said, “No, we can’t have a second black hole.” NOLAN: Can’t do it. THORNE: So I said, “OK, well, it’s a bit of a cheat, but you can use a neutron star.” NOLAN: And we do. THORNE: For me the thing I most wanted was that the film have real science embedded in it—a range of science, from well-established truths to speculative science. This is what we wound up with. And I’m just so pleased. NOLAN: It all had to be done right for us to trust the bigger things we were doing. Early in Interstellar a spacecraft docks with a larger one. It was one line in the script. But it winds up being quite a lot of screen time because—well, there are two types of science fiction film. There’s the type where something like this would be scary and important for people doing it for the first time, and you go through that detail. And then there’s the kind of film where you go, “There’s the spaceship!” And then you cut to the characters sitting in fancy chairs, they hit the button, and we’re off! You have to clue the audience into which approach you’re taking. Then the bigger ideas, the more adventurous scientific ideas, start to gain credibility. Your audience starts to take them a bit more seriously.
Great review, this is pretty much how I would review the movie. It is on such a large scale in many ways that I do not know if I caught everything about it. However, I don't think my review will change much when I see it a second time.
I really regret posting that review now that I've seen the movie. Some physics-ish reaction. Spoiler There is more physics and more good, advanced physics in this film than anything I can remember seeing, especially with a $100M+ budget! 1. The General Relativity is, for the most part, quite good. What's very cool is we literally don't know what goes on inside the event horizon, so that gives the director a lot of license. Some, like the grumpy astronomer above, have complained about tidal forces ripping everything apart, but two things there. A. As Kip Thorne noted in the interview above, he actually did some calculations for one hypothesized type of black hole that could have a planet orbiting that closely. B. As I understand it, a super-massive black hole actually has a very gentle event horizon. You would hardly even know you had passed it at first. 2. There are also complaints about "well what is lighting the planets if you only have a black-hole." Well, duh, the super-bright accretion disk, I would guess. Yes, it is a big problem that it would be emitting so many X-rays that everyone would die, quickly, but I am totally willing to forgive that. I mean, come on. Solar radiation would have killed Dave in 2001 too, for that long a journey, in that skinny of a ship. Still an awesome (and much better) movie. 3. I actually *really* liked all the stuff about a 5-D being looking at time. The mountains and valleys analogy is just fine for the purposes of the movie and being very thought-provoking. Cool stuff. And the tesseract was well done, even if the emotional plot stuff felt lame at times -- "STAY!" -- it was all very clever and right in Nolan's wheelhouse. Great effects and really interesting idea. 4. The spinning ship coming apart was just fantastic. 5. The lamest part for me was just the idea of surviving a black hole and getting pooped out somewhere else. Just didn't really need that, but it served the plot I guess. I don't believe any sort of being will be powerful enough to save people from the ultimately collapse of a black hole. 5B. Same beings can create a wormhole. From what general relativity says, this seems like a wormhole would take infinite amounts of energy to create from scratch. Also, by definition, there should not have been a "tube-like" journey through the wormhole, as per the movie's own discussion of dimensionality. It's a 4D space with a 3D opening. Whatever. I *loved* that they correctly had a 3D opening for the wormhole and they could have tried to stick with that level of science and just had them poop out on the other side (maybe a lot older or something but nothing like a Disneyland ride). 6. The plot part I didn't like was the "oh, it's us!" aspect of these 5D beings. *Really*? I think what made 2001 so amazing, creepy, and moving was that some sort of very strange extraterrestrial force was pulling the strings, leading us along. Would have vastly preferred that the makers of the wormhole and the tesseract remain mysterious. Anyway, if you're on the fence and like science at all, go see this.
All that is fine but here is what I am not understanding: Spoiler Cooper gave himself the coordinates to NASA using the sand. How did he get there in the first place? It would've made sense to me had they not shown the scene where he gave the coordinates but that has me confused.
Spoiler Yea, that's the bootstrap paradox that didn't really sit well with me, and was the single thing in an otherwise fantastic film that I didn't like. Same thing with the wormhole, if "they" are humans from the future, there's no way "they" could have put a wormhole there if it wasn't there in the first place.
I saw it over the weekend with my son in 35mm. His comment while we were leaving the theatre? "Pure science fiction. I loved it!" Like B-Bob and others, I was surprised at how much I enjoyed this film. Anyone sitting on the fence should see it.
It is science and it is also fiction. There is truth in both of those elements Ambitious but no grandeur
Spoiler I mentioned this earlier but to repeat myself. Cause and effect don't work the same way that we perceive of at the quantum level and a black hole is essentially where the space time is compressed down to the quantum level in a singularity. So the paradox that Cooper sends the coordinates to find NASA's secret base in the future and that future humans where able to construct a wormhole in the past allowing their existence may be possible because they can manipulate time at the quantum level. Also the idea of aliens who experience time simultaneously affecting the actions of humans and their own history isn't new for Sci-Fi. It's a central premise of Star Trek Deep Space Nine where wormhole aliens / Prophets also exist in a wormhole allowing for travel from vastly different parts of the Universe perceive time simultaneously rather than as past or present as we do. Because of that during the story arc it is revealed that things that happened in the past have been set in motion in the future from our linear perception of time.
The more I think about the movie the more I like it. While the "love" speech by Hathaway was clunky the more I think about it the more important I think it is to the story. Spoiler Since the future humans know that Cooper and Murphy are vital to the survival it makes sense that they manipulated things so that they did save humanity. To borrow again from DS9 this is a prophecy paradox. At beginning since this story is about them we know that those two are crucial for the survival of humanity. In other words the prophecy is they save us and are given mysterious and miraculous clues to guide them. It is later revealed how it was done involving the manipulation of time by Cooper in the relatively near future (within decades of the start of the story), seeming to fulfill the prophecy. Except at the end of the movie the prophecy hasn't been completely fulfilled. There still is the element of far distant future humans who can construct the Tesseract and wormhole to make the manipulation of time possible. So even though Cooper has saved humanity at the end of the movie there is an unknown amount of time between then and when future humans can build wormholes and tesseracts it still is a prophecy that has yet to be fulfilled. Once humans advance to that point only then do they fulfill the prophecy by making it possible for events in the past to unfold that way. This is why love becomes critical to the story. Presumably the far distant future humans could've manipulated things so that Mann, Miller, or Edmonds (the other astronauts who first went through the Wormhole) saved humanity yet it was Cooper who did. What made Cooper different than any of those other astronauts was that he had a family and a very strong attachment to this daughter. Mann's crazy ramblings about the survival instinct when it came to family actually mattered as it meant that only an astronaut like Cooper would be willing to make the sacrifices required to save humanity since he wasn't acting in the abstract but for his daughter, but also have a strong enough tie back to his daughter to reach back from the future. It was because Cooper and Murphy loved each other enough that they could both contact and understand each other across time whereas two people who didn't have as strong of a tie might not have been able to. In that sense love really was quantifiable as love was what brought the adult Murphy back to her old room and to find the watch while it was love that allowed Cooper to understand how the Tesseract worked by trying to send the earlier message to Murphy to tell his past self to stay.
rocketsjudoka, that's pretty much how I've come to digest it as well. Even though it's a little corny, I have some respect for the intent and vision. It's a way to try to bridge character and science within one entertaining movie. (And to justify a Mahler-esque soundtrack!)
Spoiler I just wished they could have shown how the world was in peril. They only focused on Cooper's family and they didn't ever look too famished in the movie.
nope everyone looked well fed... Spoiler Including fat ass Matt Damon who should have gone awhile with out food and would be rationing his supplies [\SPOILER]
Same here. The more I read this thread the more I actually realize it's a lot better than I gave it credit for. Originally put it at about a 7/10. I want to see it in imax next time.
I suspect that Spoiler Nolan intentionally left a dual ending in order to appease any potentially dissenting audiences. For example, scientifically-inclined viewers have posited that there must have been some interdimensional cooperation between humans living in different timelines--meaning that the tesseract truly was created by future humans, it's just that those future humans existed in a different timeline in which they had ascended to 5th dimensional whatever and such. This has been suggested by the unexplained downing of Cooper's take-off in the beginning, as it could've possibly been that those future humans had intricately planned out an entire sequence of events that would ultimately lead Cooper to the tesseract in the black hole. Had Cooper gone on the original mission into the wormhole after succeeding in leaving the atmosphere in that original dream sequence, he wouldn't have been around to go on the secondary mission in which he would make it into Gargantua. This is supported explicitly by what Cooper says while in the tesseract--though the viewer is under no real obligation to believe that what he is saying is literally correct--and is also hinted at when Mann claims that humans have not yet evolved to a point where they can truly empathize with people outside of themselves, which future humans would presumably have done. The other explanation is more in line what you've suggested here, and that is that Brand's speech about love being a mysterious "dimension" all its own is what came to play in the blackhole, in which his deep connection with his daughter manifested itself in some near-death phenomenon in which he was able to alter time itself. This is supported by Brand's speech, Mann's comments about how the "last thing you see before you die is your children", and the fact that after Cooper wakes up in the hospital bed they claim that they recovered him moments before he was going to die. Ultimately, I think Nolan left these two potential endings to appease both sides of the audience, and offered lingering bits of evidence throughout that could realistically support either interpretation. The science people could choose the science-y explanation, and the love/spiritual people could choose the love/spiritual explanation. Personally, I choose to appreciate the movie on a purely aesthetic level and to take it or leave it on artistic terms. The predestination paradox did bother me after a friend pointed it out, but after working it out for myself (as I've written above), I've actually gained a deeper appreciation for the movie. To close, I personally think we witnessed a modern classic.
Love is the one thing that trancends time and space. May be a bit corny, but that speech really does connect to all the different elements of the movie.
Watched it at Bob Bullock: Nolan tells a great story again! I went in there ready to accept any premise, and I feel fully satisfied in understanding the ideas I think he was trying to put across. To B-Bob's point about the special effects: bang on! Everything used was just as a backdrop for the story! No effects for the sake of effects and no gimmicks! That really earns my respect for Nolan the story-teller. He really is a great story teller. Spoiler Couple of things that I was uncomfortable with but am making peace: 1) His daughter's communication of the bedroom library/sand phenomenon. She wasn't clear with her thoughts, obviously not as a kid, but even as an adult I felt her character didn't convey the profound nature of her a) lack of understanding & b) reconciliation of the phenomenon. 2) I have to think that the ending was all in Cooper's mind: I like the ending, but part of me needs to believe that Cooper died entering the black hole, and the rest of the movie is just his mind playing out the end minutes by reflecting on his daughter, his life, and his end. 3) I think Cooper is an utterly selfish character in his desire for adventure or exploration. The movie tried to justify that aspect of his nature, but I find it difficult to accept that his leaving was anything other than fulfilling his own needs.The final scene of him leaving for more exploratory work following Hathaway supports that thought. 4) Why did we need to anthropomorphize the robots so much? Why not have another human character in their place? I didn't really consider the robot a robot, and neither did the characters in the movie. They were just a story telling tool for the characters to take a few moments to explain the science or the rationale behind some of their decisions. 5) Hathaway's love motivation wasn't developed enough, but whatever... she believes she understands the situation enough to feel that there's equal risk in following the data and in following her heart. OK. That's her opinion and I can't fault her for it. There's a few more things that caught my attention, but nothing enough for me to have a problem with the movie itself. I'd rate it an excellent 9/10 Edit: Just read rocketjudoka & Apps posts on this page - nice perspectives... summarizes two of my branches of thoughts nicely
