Howling:Cracks Causing Paradoxes

So everyone seems to think that the cracks erasing events cause paradoxes (such as the common "if Rory died saving the Doctor but then was erased, who saved the Doctor?" or the "If Rory was absorbed because he was dead, how can be be dead if he never existed?"). But they don't. People are bringing up the "if you change the past it affects the future" argument, but that's only for interfering with events, not removing them completely. The cracks erasing someone do not alter the physical or mental status of the present, unless that event or person was directly part of their past, even then, only affecting their mental status, not their physical one, as shown in Cold Blood. Thoughts? The Thirteenth Doctor 20:34, June 2, 2010 (UTC)


 * The past rewrites itself around the missing person. Past events still happen but they happen differently. For example, instead of Rory bringing Amy to the school in VoV maybe it was the Doctor that did it instead (but only from Amy's point of view, not the Doctor's). This seems to be the hardest thing for people to understand. A paradox would only have happened if someone went back in time to erase someone by preventing conception. The cracks do not work this way. You can almost say that they are intelligent in the way they rewrite events to avoid the paradoxes (changing one person's view of the past and not someone else's). V00D00M0NKY 23:24, June 2, 2010 (UTC)
 * i think it's quite simple, rather than physically rewriting the events, it merely erases the memories of that event, the event still happened but for the most part it has been erased.
 * So rory still did all that stuff, it's just that no one remembers it.


 * We don't actually know that the cracks don't work this way. All we know for sure is what we've been told--the Clerics, the Angels, and Rory (and probably the CyberKing and the Journey's End Daleks, although the Doctor may be just guessing there) have ceased to exist. "If the time energy catches up with you, you'll never have been born. It will erase every moment of your existence."


 * But, either way, as I've said elsewhere, the cracks don't add anything new that Doctor Who hasn't already dealt with before. The Doctor and other time travelers rewrite history all the time (in the novels even more so than on TV), and that has exactly the same potential for creating paradoxes as when the cracks do it. However you (or the writers) choose to deal with all those other paradoxes, it works just as well for any crack-related paradoxes.


 * Speaking of which, the first Adventure Game gives us new information on how the paradoxes are avoided. Amy should no longer exist--the Doctor explicitly says that he existence is a paradox. But first the TARDIS and then a special "chronon blocker" are used to (temporarily) shield her from the chronons that would remove her from the present. Presumably the time field that seeps from the cracks is chock full of chronons, so Rory is erased from the present at the same time he's erased from the past. But the ring is shielded by being inside the TARDIS, so the chronons can't get to it, meaning it still exists in the present even though its past is paradoxical. (The fact that TARDISes can do this ties in pretty well with the fact that the Master was able to turn the Doctor's TARDIS into a paradox machine--basically, all he had to do was channel all of its energy into shielding local space from the chronon flux.) --Falcotron 13:20, June 3, 2010 (UTC)
 * Ok, that all makes sense but wouldn't that mean that the TARDIS would shield Amy from forgetting Rory? V00D00M0NKY 15:39, June 3, 2010 (UTC)


 * Well, now we're getting even more speculative. But I don't think so.


 * Why? Well, that's the question.
 * You could argue that Amy is straddling two time tracks, one where she's forgotten Rory and one where she hasn't. Chronons have nothing to do with it anymore; it's just a matter of where she puts her metaphorical foot forward when the two paths diverge.
 * It's also possible that the writers are just thinking that memory isn't a physical thing like an engagement ring or an Amy (which is kind of silly philosophically--if a person is just a physical entity, how are her memories not just physical entities?--but that doesn't mean it couldn't be the writers' intention...).
 * A third possibility is that the TARDIS can only do so much shielding (which they pretty much say in CotD--that's why you have to build the chronon blocker), and an engagement ring is just a much simpler and/or smaller thing than a whole mess of memories. Protecting Amy's memories was just barely within the TARDIS's capabilities, but it needed help from Amy (remember, it can empathically link with its travelers, so this isn't too unreasonable), and it just didn't get quite enough. --Falcotron 15:53, June 3, 2010 (UTC

I think that there are different versions of events and these are in conflict. This is not quite the same as a paradox; the two (or more) versions coexist until the resolution. These versions can be resolved in a few ways:

They all can be let stand – does it really matter that there are two versions anyway?

The versions we see can stand.

The versions everybody else see can stand.

A combination of all of these things allowing selective events to be removed from reality can stand (a nice retcon).

I think that the resolution depends on Amy’s memory of events, particularly the Doctor. Imagine that the TARDIS actually exploded when the engines were failing in the eleventh hour. It has already happened the Doctor is erased by the space time rip caused. His past is being erased by the cracks (they are all the same one coming to get him and take away everything he has done). What we are seeing in this series is this removal process.

Memory and observation are ‘special’. The removal of the Doctor is not final until he is forgotten and he (an alternate, or future Doctor) is trying to ensure that this does not happen. It all rests on the few minutes he was with Amy before the explosion. She was not another special person until the doctors made her so. She is the only observer of the doctor between the regeneration (the initial cause of the explosion) and the explosion itself.

The Big Bang is not the TARDIS exploding it is the actual Big Bang. This too will fall into a crack that it attempting to remove the Doctor (the only way left is to remove him is to remove everything). There are no conflicting versions, no paradoxes. Silence will fall … Jack Chilli 10:13, June 9, 2010 (UTC)


 * Please don't edit other people's posts. I put mine back the way it was, and fixed the formatting, because I couldn't understand what I was saying the way you rearranged it, so I doubt anyone else could either. --Falcotron 00:02, June 11, 2010 (UTC)


 * Anyway, as I've said elsewhere, I think maybe both timelines do exist, as you suggest, and that's not a paradox at all (although there may be paradoxes in the history of the non-Rory timeline), and it doesn't even have to be resolved. The only thing that needs to be resolved is, which timeline is Amy on? --Falcotron 00:04, June 11, 2010 (UTC)
 * Sorry. I did not mean to alter your post, this editor does not seem to be working very well on this laptop. I'm trying to get better at the layout but sometimes a wisywig editing panel pops up (and most of the buttons don't work) and sometimes a plain text (with special formatting commands) pops up. Must be something to do with the source buton; I'll investigate. Jack Chilli 08:08, June 11, 2010 (UTC)
 * Sorry. I did not mean to alter your post, this editor does not seem to be working very well on this laptop. I'm trying to get better at the layout but sometimes a wisywig editing panel pops up (and most of the buttons don't work) and sometimes a plain text (with special formatting commands) pops up. Must be something to do with the source buton; I'll investigate. Jack Chilli 08:08, June 11, 2010 (UTC)


 * Not your fault. I'm horribly annoyed with the rich text editor, but not with you or the other people who use it because that's what Wikia gives them by default. It's getting better, but it's still buggy as hell.


 * If you don't mind editing in wikicode (which I personally find is almost always faster and easier, but then I also think emacs is easier than Notepad...), you could just disable the RTE completely. Go to Special:Preferences and unclick the first checkbox and it's gone. Occasionally, the RTE actually is useful--mainly when pasting in already-formatted text from elsewhere; in that case, I'll temporarily turn it on, make the edit, and then click the Source button to make sure it didn't do anything stupid.... By the way, the reason you sometimes get the wikicode editor (unless you're accidentally clicking Source) is that some features have known bugs with the fancy editor, and it automatically disables itself if you try to edit those pages.


 * Anyway, back on subject: if the time energy is going to absorb the entire universe, there obviously won't be any paradoxes left. Does it matter if some are "temporarily" created along the way? Maybe there's some analog of Heisenberg's uncertainty principle at work: You can "borrow paradoxes" as long as you pay them back on time, just as you can "borrow energy". And, in the same way that inflating the early universe faster than light effectively stretches the time allowed for a virtual universe to exit out to infinity, deflating the universe faster than light would mean that the time is effectively zero. --Falcotron 13:04, June 12, 2010 (UTC)


 * In a sense there seems to be a sort of Meta-time (or hypertime or ultratime) that seems to be available to time-travelers. When Rory was erased these was 'time' before Amy and the Doctor would forget him (which should happen 'instantly' if he is erased because he always has been erased) giving the apparent pardox that he was erased but remembered for a small period.  I think you mentioned something similar in the adventure game where Amy begain to cease to exist due to a possible paradox forming but there was 'time' to fix it (extended by some TARDIS magic).  There could be something like an amount of this Meta time being allowed in which a paradox can stand until it is eventially resolved (this somehow pays back this borrowed metatime).  If the paradox is not resolved then the things we see during the meta time did not ever happen (possibly including the borrowing of the meta-time).  Luckily we usually only get to see situations where the paradox is actaully resolved (eventulatlly) so the problem goes away.  So in a similar way that you can 'borrow energy' you can borrow time (or meta time) as long as the paradox resolves.  If the paradox does not resolve then you never borrowed the meta time in the first place!


 * Is there a science of Doctor who book that tries to explain how stuff is supposed to work? Jack Chilli 16:55, June 12, 2010 (UTC)


 * After hearing Moffat talk about doing a real time travel story, I started to think about how you could come up with a consistent theory that fit with most of what we'd seen in Doctor Who and with what Moffat was saying, and it was exactly the kind of meta-time theory you're talking about. The key is that you can have a dynamic 4D spacetime, where history can be rewritten and all that, if it's embedded in a static 5D meta-spacetime, which works pretty much the way you'd expect from relativity as we know it. It took me a while to figure out how the Web of Time and fixed points and all that fit in--but it actually does work. The idea is that you want a continuous 4D hypersurface that everyone lives on. The 5D universe doesn't change, and you can't travel in metatime, and you couldn't pick up everyone in the universe and move them in your TARDIS anyway. So, you have to find ways to curve the hypersurface from within it. Sort of like warp engineering, but you're engineering history instead of just creating shorter paths across the galaxy. Of course it should take continuous energy input to keep time warped in this way while people keep traveling in time (just as a "warp gate" would collapse without something to power it), but this is a universe that already has things like "charged vacuum emboitments" to funnel entropy out of the universe, so maybe that's not a problem.


 * So, how does that fit in with the paradox thing? The problem in Amy's case (and the Toclafane's, and everyone else with certain kinds of paradoxes) is that a chunk of this surface has pinched off from the rest, and if pinched far enough it'll break. Essentially, given enough metatime, Amy would be part of a pocket universe with nothing else in it, instead of part of our universe, leaving our universe continuous but Amyless. I'm not sure how chronons really fit into the picture, but think of time energy as analogous to gravitational energy without trying to understand it. If you could block gravitons, you could warp space as far as you wanted without it locally collapsing into a black hole; if you could block chronons, you could similarly warp history as far as you want without it locally collapsing.


 * Of course that doesn't really fit in at all with the uncertainty idea that I suggested above and that you just extended. You can connect the two--if a paradox essentially disconnects a portion of spacetime from our shared surface, it doesn't have to be "paid back" on our side, because we never "borrowed" it in the first place. It's a bit worrying that there are partial explanations from both viewpoints, but I don't know how to put them together, and both sides explain some of the same things. But really, the situation with more mundane things like black hole thermodynamics is identical--relativity explains about 2/3rds of it, quantum mechanics explains about 1/2 of it, and there are bits that are explained by both theories in ways that we can only hope will turn out to be the same once we work out M-theory or loop quantum gravity or whatever the grand unification turns out to be. If real-world early-21st-century physics can't do any better than that even for a universe without time travel.... --Falcotron 02:42, June 13, 2010 (UTC)


 * I just realized I got caught up in your ideas and forgot to answer your last question. There are a few of these books. I think the most recent is Paul Parsons' The Science of Doctor Who, which is designed to look like it's part of that series of The Science of X books but actually isn't. It's mainly about things like how a robot dog is a plausible centuries-later development of the robot spiders we've designed for space exploration, how our genetic engineers borrow from accidental radioactive mutation just like Davros did, etc. The discussion of time travel is mostly limited to a simple "Here's what general relativity says about closed time loops, so time travel really isn't impossible" that you can find much better in Kip Thorne's books. The only other one I've read is Michael White's A Teaspoon and an Open Mind, which pretty much just used Doctor Who are a starting point to jump off into unrelated directions. As far as I know, there's no book that says, "OK, go off and read Kip Thorne and Julian Barbour and David Deutsch, and then we'll give you a consistent explanation of how Doctor Who time travel works." The best you'll find is discussions like this on the two major fan forums and here. (The alt.drwho hierarchy had a pretty decent number of geeky physics grad students and the like who enjoyed arguing about these things, and could tell me, with equations, where I was being stupid. But sadly, Usenet was pretty much long dead by the time the new series started.) --Falcotron 02:56, June 13, 2010 (UTC)