“Um,” Harry said, “can we go get the healer’s kit now?”
McGonagall paused, and looked back at him steadily. “And if I say no, it’s too expensive and you won’t need it, what happens?”
Harry’s face twisted in bitterness. “Exactly what you’re thinking, Professor McGonagall. Exactly what you’re thinking. I conclude you’re another crazy adult I can’t talk to, and I start planning how to get my hands on a healer’s kit anyway.”
A time turner is a superior to a healer’s kit in very nearly every way and by a huge margin. Yet all Harry does when he loses free access to his time turner he sulks a little and that’s all. He doesn’t plan at all! I don’t even recall one line of introspection on the subject! It takes very little ingenuity to to react:
“Harry, give me your time t...”
shit. shit. shit. Activate time turner. Escape. Then, he can spend five minutes and think up a dozen ways to retain time travel capability. Let me see...
Create a fake…
Lie to Hermione to get assistance?
Transfiguration not likely to work, given the teacher responsible.
assume that wizarding security is crap and guess (correctly) that he can probably steal one if needed...
actually leave Hogwarts because the time turner is more important and money can buy a better education anyway.
Ask Fred and George to discover a way for him to hide, to give him more time to plan.
Leave Hogwarts for a week.
Fill Gringots with silver.
Use money to buy a time turner on the black market
Also buy that hand-light that Malfoy bought.
And in general a stockpile of the most powerful and useful artifacts available.
And the best trunk that can be found anywhere or created for cash.
Return to Hogwarts if they will accept him after the week is up. (Or, for that matter, do it in the holidays. There isn’t that much of a rush.)
If circumstances demand, buy an education from one (or all) of the other schools.
Hire all the best tutors available for all subjects and use them to supplement school education with or without the cooperation of any teacher at the school, further insulating him from the ability of the teachers to f@#% with him or take his stuff.
Really… the best Harry can come up with is to say “that’s not fair”? WTF?
First, Harry discovered a gag beverage that he thought could be a key to power, although he quickly realized the Comed-Tea wasn’t as powerful as it seemed. A few days later he fell in love with a device that is sometimes given to students who want to take extra classes, although he has since discovered some limits to its powers. If he goes rogue over his Time-Turner’s crippleware, then who knows how much other cool and useful magical stuff he will miss out on, and how much trouble he’ll be in.
Plus, McGonagall had him cornered when she confronted him about returning the Time-Turner—whatever he tried to do, she’d see it. Also, McGonagall had earned some degree of trust & respect from Harry, she’s correct about Harry repeatedly misusing the Time-Turner, and she’d already warned him that they’d take it away. So it’s not unreasonable to go along with the punishment, and try to earn her trust back so that his Time-Turner can be restored later on.
...don’t take this the wrong way, but even Harry knows better than that.
There is NO DOWN SIDE!
It may be best to hand over the time turner but you do so after having a chance to think it through. Time turner. Plan. Decide that it is better to hand over the device for now. Write your analysis down. Give it to yourself at the appropriate time. (And give it to yourself again to make the loop stable.)
If you genuinely think this is a smart thing to do in real life, it makes me seriously worry about your safety and the safety of people around you.
I have offended you by questioning the rationality of your fictional persona. My own safety is not in any danger. Every other exceptional use that Harry put the device to is risky and I would not do any of them. But giving himself a chance to think through his options in a way that would not be detected by anyone else is the trivially correct strategic option.
My own safety is secure in the short term, and medium term (human life span) but for the long term the threats to my life are human mortality and existential risk. And that’s kind of what I’ve been counting on you to take care of (with any contribution that I could hope to make purely financial). That being the case, this conversation is quite literally scaring me. I’m not quite there yet, but the key quote from Snape is at least springing to my mind: “And I no longer trust your cunning.”
Examples of stupid things to do with a Time Turner:
Throw pies at people through misguided altruism. It would be better to let them break your finger. You’re at Hogwarts… a 5th year Luna could fix it.
Have a dramatic stand off over a rememberall. If it is so important… use the time turner to find and or steal the thing beforehand and leave it somewhere Neville will find. I mean seriously… using a time turner in a way that is detectable is for emergencies!
Disappearing acts from a class room. Of all the things to do with a Time Turner in that situation making a bigger scene is not one of them. At the very least, if you must refuse to be bullied, write yourself a note telling yourself to not attend potions and make another arrangement. It would be much easier to convince Dumbledore to allow Harry to hire potion tutors than have a full on confrontation.
Not using the time turner to go back and prevent the entire situation, after writing a great big essay to your past self on what happens if you mess with those in power.
Now, all the above mistakes are credible for Harry to make. At least, they fit the needs of the story. But using the turner to give yourself time to think at a critical moment… not on the list. And make no mistake, giving up one of the most powerful super-powers (even in the weakened 6h form) is an extremely critical moment.
But now another lesson from Harry Potter: MOR occurs to me: Always be sure you know exactly what you are both talking about. I may well be missing Eliezer’s real message.
If you genuinely think this is a smart thing to do in real life, it makes me seriously worry about your safety and the safety of people around you.
What are we really talking about here? Being as EY may be several levels ahead of me the intended ‘this’ could be “implying that a respected authority is obviously wrong without a clear benefit to yourself”. That would make for extremely good advice, and a valid concern. Fortunately I for most part avoid that in real life. It does cost me and I do limit my options such that my environment doesn’t put me in that situation too often. One way to ensure my safety is to not put myself in situations that prompt risk taking. It isn’t optimal, except in the bounded sense, but it does work.
It may be best to hand over the time turner but you do so after having a chance to think it through. Time turner. Plan. Decide that it is better to hand over the device for now. Write your analysis down. Give it to yourself at the appropriate time. (And give it to yourself again to make the loop stable.)
You seem to misunderstand how the time-turner works (or at least, how it’s been suggested it works). You don’t get to overwrite anything; the universe doesn’t “end up in” a stable state that results from using it; there isn’t any meta-time (or at least, we’ve seen nothing to suggest such). If he were going to use the time turner to give himself advice, he would have already gotten the advice. And having used the time-turner right there and visibly, he couldn’t use it “later not use it there” and have his going back in time undetectable.
A possible way he could use the time turner to help himself in this case would be to ask to go to the bathroom or somesuch, use the time turner, use the extra time to think, and then return to the room shortly after he left having thought about things.
(Edit: But this would be pretty obvious, and McGonagall probably wouldn’t let him leave the room with the time turner in any case.)
You seem to misunderstand how the time-turner works (or at least, how it’s been suggested it works). You don’t get to overwrite anything; the universe doesn’t “end up in” a stable state that results from using it
My interpretation of the “DO NOT MESS WITH TIME” incident was that you can try setting things up so that temporal consistency implies the result you want, but actually ruling out every other possibility whatever, including vast classes of outcomes you never even imagined, is next to impossible, at least for an 11-year-old boy, however smart. It hadn’t even occurred to him that there was a problem in his reasoning when he tried the experiment that gave him “the scariest result ever in the history of science”. Temporal consistency in the presence of time loops is another blind idiot god, far more swift and powerful than evolution.
Anyway, he still has the Time-Turner. All that stands between him and it is a magical lock. How difficult can that be for him to get around? No, actually what stands between him and it is the author’s necessity not to unbalance the plot by giving him a get-out-of-jail-free card.
Harry’s error in the experiment was responding to “DO NOT MESS WITH TIME” with the same. If he didn’t have the property of responding to that message with the same, that message wouldn’t appear.
Actually, this whole consistency-based time travel seems to be an extremely expressive thought experiment infrastructure for thinking about Newcomb-like problems and decision theories able to deal with them. Maybe I should do a top-level post on that (I don’t have a sufficiently clear picture of the setting, so I might be wrong about its potential)… Though I consider that happening unlikely, so other people who understand UDT are welcome to try.
I was thinking exactly the same thing. After getting my head around the implications it seems to be an extremely intuitive way of handling such problems. I didn’t write a post myself since I have yet to look close enough at UDT to be able to explain the difference between UDT and TDT.
My interpretation of the “DO NOT MESS WITH TIME” incident was that you can try setting things up so that temporal consistency implies the result you want, but actually ruling out every other possibility whatever, including vast classes of outcomes you never even imagined, is next to impossible, at least for an 11-year-old boy, however smart. It hadn’t even occurred to him that there was a problem in his reasoning when he tried the experiment that gave him “the scariest result ever in the history of science”. Temporal consistency in the presence of time loops is another blind idiot god, far more swift and powerful than evolution.
I think you summed that up perfectly. I would have liked to see a little more of that explanation in the Fan Fic. It would make the story feel more natural and also be a perfect excuse to include the ‘blind idiot god’ kind of message.
Anyway, he still has the Time-Turner. All that stands between him and it is a magical lock. How difficult can that be for him to get around?
Without Hermione backing him up? I think he’d struggle. Harry just isn’t that smart! He really should be spending more time sweet talking her. Well intentioned genius with ambition that doesn’t involve gaining power… just the kind of ally Harry needs.
No, actually what stands between him and it is the author’s necessity not to unbalance the plot by giving him a get-out-of-jail-free card.
Uh huh. It’s even worse than if Harry had actually gone and made himself rich on day 1!
once McGonagall sees Harry disappear, he can’t undo it.
Sounds like UDT might be applicable here. Here’s a time-traveling version of Counterfactual Mugging:
Harry appears to McGonagall and tells her, “If you give me 1 Galleon now, I’ll go back in time and hand you 100 Galleons an hour ago.” Suppose McGonagall does not recall being handed 100 Galleons an hour ago. What should she do?
Here’s my analysis. Suppose McGonagall decides not to give Harry 1 Galleon, then there are two possible consistent timelines for this universe. One where McGonagall gets 100 Galleons, and one where she doesn’t. How does the universe “choose” which one becomes reality? I don’t know but let’s say that the two possibilities have equal chance of being true, or get equal amount of “reality juice”.
Given the above it seems clear that McGonagall would prefer to have pre-committed to “give 1 Galleon even if not handed 100 Galleons an hour ago” since that would make the “not get 100 Galleons” timeline inconsistent. I think that’s also UDT’s output (although I haven’t written down the math to make sure).
ETA: I didn’t follow the previous discussion closely, so this might not apply at all to it. Hopefully, in that case the above is of interest in its own right. :)
Seems straightforward to me. McGonagall knows that she does not recall being handed 100 Galleons an hour ago, so the three states of the world with high probability are: 1) She is not in a universe where she will hand Harry 1 Galleon, 2) She is in a universe where she hands Harry 1 Galleon and Harry breaks the agreement, or 3) She is in a universe where she hands Harry 1 Galleon and Harry keeps the agreement in a way that leaves her unable to recall this happening. By not handing Harry a Galleon, she will ensure that she is in universe 1. By handing Harry a Galleon, she will find herself in universe 2 or 3. She should therefore give Harry a Galleon if she judges it less than 99 times more likely that Harry will break the agreement than fulfil it in a way consistent with her experience.
As Harry has access to a time machine, he doesn’t need to decide to give her 100 Galleons before he gets the 1 Galleon, so the situation is quite different to one based on predicting her actions, as Omega does in the Counterfactual Mugging. Rather it has most of the properties of the forward-time version of the gambit: “If you give me 1 Galleon now, I’ll hand you 100 Galleons in one hour”, except that McGonagall has a big piece of evidence that the promise will be broken, namely that she doesn’t remember it being kept.
ETA: I didn’t follow the previous discussion closely, so this might not apply at all to it. Hopefully, in that case the above is of interest in its own right. :)
Vladmir and I agree with the applicability of UDT and have suggested time-travel-with-consistency is a good way to consider Newcomblike problems and the the decision theories that can handle them.
Suppose McGonagall does not recall being handed 100 Galleons an hour ago. What should she do?
Precommit, give him the Galleon, then reach in her bag to get the 100 Galleons. (She must have been Obliviated; otherwise, she would remember.)
You can actually get around a lot of the problems with time travel by taking advantage of the difference between observation and reality. For instance, if you see one of your friends die, you can go back in time, save him, then plant a fake double so you still have the same observations.
Though Godel was interested in time travel loops, that’s not the type of consistency that his Second Incompleteness Theorem discussed (it’s limited to formal axiomatized systems that can describe arithmetic).
It seems we can’t rely on setups, which include decision making inside time loop, because it is not clear who or what makes decisions (agent? consistency law? agent’s preferences?).
It seems I can’t rely on setups, which include decision making inside time loop
If you say ‘we’ you invite contradiction as your stance implies magical thinking about decision making which not many people would want to admit to. Decisions are not a special case. If gravity works you can build a gravity powered mechanical device that makes a decision.
Either you treat decisions exactly as you usually would or nothing works at all.
Can I be in the one where the ‘created information’ is a a freak quantum conversion of graphite into diamond and not the one where the created information is freak quantum effects making my neurons fire in a way that they normally wouldn’t?
You can be there, no problem. The problem is to setup everyting to get there. I’ve just considered the question of setting up, and found that I can’t say even what causes existence of time loop. Can you say what should I do to be sure that no matter what after 1.01 hour I will timeturn 1 hour back? Being the person that will do that is important, but it will not help if in 20 minutes someone will steal my timeturner.
Returning back to 6(grand)parent, I can say, that imposing any condition on a stable state of time loop (but initial conditions before time loop) seems unphysical. All in all, thought experiments with time loops are interesting, but their validity is highly questionable.
Eliezer can do that, because he is consistency law of Harry’s universe.
You can be there, no problem. The problem is to setup everyting to get there. I’ve just considered the question of setting up, and found that I can’t say even what causes existence of time loop. Can you say what should I do to be sure that no matter what after 1.01 hour I will timeturn 1 hour back? Being the person that will do that is important, but it will not help if in 20 minutes someone will steal my timeturner.
Go think about it some more from the perspective of an integrated physics that happens to include time travel of this kind and not as a special case. That seems to be confusing you.
Eliezer can do that, because he is consistency law of Harry’s universe.
Eliezer can have Harry become a Hari Krishna if he really wants. Or he could artificially select for extremely improbable quantum events either inside or outside of time loops. Neither of those would make for an especially good story in this instance.
A trolley is running out of control down a track. In its path are 5 people who have been tied to the track by a mad physicist. Fortunately, if trolley ran down different track, it would activate timeturner that would send it 10 seconds back in time and then trolly would flip a switch, which will lead the trolley down a different track to timeturner. And also a bystander runs to flip a switch.
Possible stable states.
Bystander stops and wait for trolley to appear from nowhere. Trolley kills 5.
Bystander stops and wait for trolley to appear from nowhere. Trolley appears from nowhere and flips the switch, then original trolley runs to timeturner and disappears.
Trolley appears from nowhere kills bystander, which almost managed to reach the switch, and flips the switch, then original trolley runs to timeturner and disappears.
Bystander appears from nowhere and flips the switch, then original bystander runs to timeturner and disappears. Trolley run past deactivated timeturner.
Bystander appears from nowhere shouts “watch your step!” and fails to flip switch in time, original bystander looks on timetraveller, missteps and falls, then manages to activate timeturner and disappears. Trolley kills 5.
Bystander appears from nowhere shouts “careful!” and flips switch, original bystander looks on timetraveller, missteps, but manages to not fall, then activates timeturner and disappears. Trolley run past deactivated timeturner.
Bystander appears from nowhere looks on trolley, shouts “damn! too late” and fails to flip switch in time, original bystander hearing that tries to run faster, missteps and falls, then activates timeturner and disappears. Trolley kills 5.
Bystander appears from nowhere, shouts “Shout, what I shouting now, it is very important!” and flips switch, original bystander activates timeturner and disappears. Trolley runs past deactivated timeturner.
Even in those rigid conditions stable states can be numerous without any improbable events. But yes, maybe you are right, because amount of information-from-nowhere must be limited by communication channel bandwidth (spoken or written speach, nonverbal actions of future-agent, agent’s memory throughput), thus rendering stable states in principle analyzable.
In a time loop do things still fall down? Is there gravity? And if I implement a decision making mechanism using a gravity powered system of gears and pulleys where is the magic thing that makes reason no longer apply?
Information from future will affect any kind of decision making. This information is a consequence of consistency law, it even doesn’t need to have cause.
McGonagall went a fair way towards earning Harry’s respect, with her behavior about the med kit among other things; he is inclined to tolerate (with however much whining) her authority, particularly on school grounds.
Respect is all well and good… sure, maybe he will do some detention some time. But this is a matter of survival and something that can help him in a broad manner to achieve just about all his goals.
This is compared to Snape who.… said some things that might hurt Harry’s feelings.
Harry isn’t acting like a rationalist. He’s acting like a nerdy ape.
This doesn’t warrant one sentence worth of inner dialog? Seriously not buying it. It’s a different Harry hacked together for a different parable and as a plot hack to get rid of the Get Out Of Jail Free Card of Awesomeness +4.
That’s a good reason. So are you saying that Harry actually did do a thorough analysis of his optimal strategy for securing the benefits of time travel for “actually 5 minutes” at some stage but we just don’t hear about it? This would make the situation credible.
This is actually more rational than what you are advocating.
Are you sure you understand what I’m advocating? Your claim here suggests to me that you do not.
The most probable outcome of the thought process I outlined, and I say most probable because this is what my reasoning concluded but Harry is smarter than me, is that he will go and earn enough enough money to buy a time turner just in case. I aren’t advocating the use of the time turner to make reckless experiments or any of the non-authorized uses that Harry had previously used the device for. I actually made it quite clear what I thought of clever experimentation when explaining the note I would send myself. “Arrogant git” was the key phrase if I recall.
What kind of usage is sane? Emergency usage. For example, I would advocate the use of a time turner when locked in a room being tortured and at a high risk of suicide if I do not prevent it. (I liked the touch with the destroying all sharp objects too.) I would also advocate the use for saving lives (including his own depending on circumstances) with minimalist interventions, many of which would be not at all experimental given what he has already safely gotten away with. It would also be extremely valuable in the reduction of risk to have an extra 36 hours available for emergency use. Many threats to Harry’s world optimisation plans will come with some warning. Impending attack of some sort, etc. Having a turner on hand means that he would be able to take more time to make preparations or give th device to McGonnagal in the emergency situation and allow her to prepare. As far as either myself or Harry know she isn’t wise enough to have one on hand herself.
A time turner is a device that is massively useful and it is massively useful even if you use it conservatively and take no risks with it. Having one on hand does not make bad things happen unless you know you will be unable to control your foolish impulses. This is not Harry’s reasoning.
If Harry does not spend at least five minutes thinking through his priorities (let me emphasise that again, spend five minutes) and considering how to acquire (ie. buy) a time turner then both he and the author are making a big mistake. That is not* more rational. It is a rationalization of a decision that was originally made for the purposes of plot balance.
The reasonable solution is clearly for Harry to do is to put “buy time turner” down on his to do list right next to “become ridiculously rich in a week”. It is an obvious smart thing to do but the reader understands why Harry can’t really follow through with these plans for story purposes. Having them judged “not a pressing priority” is a credible explanation.
Timeturner awesomeness for jail escape is pretty much discounted, when jailers know that one has it. And Harry risks being put under constant supervision because of his apparent disability of infancy.
Timeturner awesomeness for jail escape is pretty much discounted, when jailers know that one has it.
It never occurred to me to consider it a literal way to escape from jails. That’s nearly useless. Instead, I consider it, among other things, as a nearly universally more effective med. kit. If someone just fell off the roof would you rather be able to bandage them up a bit or go back and tell them to watch their step?
And Harry risks being put under constant supervision because of his apparent disability of infancy.
… a good reason to not do things that are infantile… and when you do slip up you go back and give yourself a scolding so that you never do the infantile thing in the first place (but still give your past self the scolding note).
Good heavens, Mr. Wedrifid, you can’t change time! Do you think students would be allowed Time-Turners if that was possible? What if someone tried to change their test scores?
Good heavens Mr. Yudkowsky, I thought the inventor of Timeless Decision Theory would have a better grasp on how being the kind of person who would make a certain decision can determine what happens, even when that decision never needs to get made, whether that be with Omega and his boxes or in the stable resolution of time loops.
In all the previous time related events, things worked out how they did because the situation in which Harry did not use the time turner was not stable. If Harry was different (for example, by being Hermione or by not having a Time Turner) then the stable, ‘final version’ given by the universe-time-loop-processor would be the simple one where he doesn’t go mess with stuff. But it wasn’t.
But lets say that for some bizarre reason Harry never found a note warning him about a stumbling risk and he didn’t think to send one back later. At the very least we should find out a few seconds later that the friend fell off the building and landed on a great big padded mat.
Good heavens Mr. Yudkowsky, I thought the inventor of Timeless Decision Theory would have a better grasp on how being the kind of person who would make a certain decision can determine what happens
I do indeed.
I’ve written unpublished fiction about it.
From before TDT was invented, actually.
Harry has not worked all that stuff out yet.
He did work out one important principle so far.
It is called DO NOT MESS WITH TIME.
And considering that he got that result, you seem to have missed some of the implications for how time travel works in that universe which would make it potentially dangerous to try and blackmail reality.
Time travel was the first optimization process I considered which was truly alien enough to deanthropomorphize my thinking; evolutionary biology didn’t do the job, but the unpublished story I was writing about time travel did.
What you’re suggesting is a bit more potentially incredibly dangerous than you seem to think.
What you’re suggesting is a bit more potentially incredibly dangerous than you seem to think.
I think you are mistaking me for straw-wedrifid here. I saw the problem with trying to blackmail reality before he went ahead and actually tried it. But then I’m not eleven and while I am arrogant I am not nearly as arrogant as Harry seems to be.
Exactly. To make certain situations impossible, you have to be the sort of person that makes the correct actions in the impossible situations, the actions making those situations impossible. (This is also at the core of bargaining.) You are not to take the money from two boxes in the Open Box Newcomb’s problem, even if you clearly see that money is there in both of them (and if you have that property, then the situation will never arise).
He was trying to create a stable time loop, which had consequences along the same lines as the Outcome Pump—there’s no way to know which stable time loop you’ll get.
However, if he was using a “being the kind of person” strategy, we might expect he’d avoid being the sort of person who would pass along “DO NOT MESS WITH TIME”.
Yes, to repeat what I said earlier, this seems easy to avoid by replacing his “blank paper” condition with a more general “anything other than a pair of numbers in the given range” condition. I have to suppose Eliezer had him get that specific message because it wouldn’t be good for the story if Harry noticed this fact. Though even if he does take that approach, as with the outcome pump, there’s still other possibilities, because they can screw with Harry’s ability to execute his intended algorithm.
Though even if he does take that approach, as with the outcome pump, there’s still other possibilities, because they can screw with Harry’s ability to execute his intended algorithm.
Yes, like it turning out that he was predetermined to die at the time of the experiment, and never complete it.
He did the same thing every time he used the time turner. I mean every time, even the times when he was being a good boy and using it to manage sleep. the universe doesn’t care whether it is a conversation with McGonnagal, juggling bullies and pies, someone falling off the roof or just bed time.
What does matter to the universe is whether the agent in the time loop is interacting with the time loop in a way that is complex and improbable. That is, factoring large primes should give unpredictable outcomes, long detailed tricks like throwing pies and playing with bullies should be slightly safer, giving yourself a time out simpler again and pre-sheduled study and sleep breaks right down at the bottom of the scale.
I argue that all the instance of time turner differ use differ only in degree. There are many things to do with a time turner that are far, far less disruptive, complex or unstable than what Hermione did when attending multiple classes. Given her interaction with other people who would be encountering her other self there are butterfly effects that would need to be resolved by the system. If Harry set up a smart system to communicate with himself unobtrusively things may be simpler to predict. He could send himself SMS messages (when outside Hogwarts) or use one of those coins to send messages.
What does matter to the universe is whether the agent in the time loop is interacting with the time loop in a way that is complex and improbable. That is, factoring large primes should give unpredictable outcomes, long detailed tricks like throwing pies and playing with bullies should be slightly safer, giving yourself a time out simpler again and pre-scheduled study and sleep breaks right down at the bottom of the scale.
As Eliezer said already, timeturner can’t change the past. One generally can’t even calculate probability of desired outcome of timeturning… Ouch. This is discussed already.
If anyone wants some sf on the subject, I recommend Leiber’s The Big Time and “Try and Change the Past”.
They’re both based on the same premise. The timeline is changeable but highly resistant. Humans can’t change it (that’s the short story) but there are two superhuman sides (called Snakes and Spiders, but never seen onstage) which recruit humans who are willing to be cut out of their timelines just before they die.
I found Vladimir’s utterance (I’m not sure of word’s connotations, I use it in pragmatics sense) incomprehensible on my current level of understanding his intentions and his ways of expressing toughts. So I’ve took literal meaning of his words into current context. However, beside joke part my message points on difficulties in dealing with stable states of closed time loops (the thing).
I found Vladimir’s utterance (I’m not sure of word’s connotations, I use it in pragmatics sense) incomprehensible
This is not an unusual occurrence. V thinks clearly, and thoroughly but presents his conclusions in a way that assumes a similar thinking style and a lot of shared prior knowledge. Petty things like ‘intermediate steps’ are not necessarily included.
Those closed time loops are weird. I considered timeturing before outcome, but, yes, even in that case one can be told by one’s timeturned twin, that all is set up for good outcome. And timeturing after desired outcome… should be done unconditionally, as you can’t know it is not you who caused this outcome. Weird.
Definitely weird. A related consideration is that I would always give reasons for any advice I give my former self. That cuts off a large swath of potential stable loops that consist of me giving myself advice for absolutely no reason at all except that it happens to be stable. The better the reasons I have been given myself the less likely it is that the self perpetuating cycle is a completely arbitrary cycle.
For example, I wouldn’t have sent back “Don’t mess with time”. I would have sent “the universe doesn’t particularly care about your rules and plans you arrogant little git! What’s more likely, guessing your way through 128 bit encryption or something seriously nasty that distracts you from your games, such as ? That’s right. Think.” (Yes, I’d include the ‘arrogant git’ part. That is information I would clearly need to be reminded of!)
Now, not all scary situations give me the chance to write an explanation but a large swath of the probability mass does. While I would still follow the hastily written directive I would also know that to write that particularly message something really bad must be happening. Without having a predetermined policy for giving details I would have no idea whether the message meant something bad almost happened or not. (It also means that I am far less likely to get such a message—I’ll probably get one of the many possible detailed messages.)
The problem is that you aren’t source of advice, you are one of constraints to be satisfied. Any message, that you will reproduce with picometer precision and that will create stable state, will do. Precision isn’t a problem in deterministic world, and maybe in quantum one too (if our neurons are sufficiently classical), but I’m hesitant to estimate influence of one’s preferences on stable state.
The problem is that you aren’t source of advice, you are one of constraints to be satisfied.
I am both. The advice that I will choose to give is determined by the same physics that allows me to breath.
Regarding quantum effects—the uncertainty effects can be amplified based on the elimination of unstable loops. Most obviously when my behavior is determined by a quantum coin. The way that plays out looks seriously when pictured in 4 dimensions.
I read the link and make the same claim I made previously: I am both. The advice that I will choose to give is determined by the same physics that allows me to breath.
Wait a second, you will not choose an advice. You will reproduce the advice (consistency constraint!).
And for the advice to be advice you choose, it must be physically impossible to you to reproduce anything you think is not of your origin. I envy your self-esteem.
Edit: Given condition is sufficient, but not necessary.
I mean that he doesn’t want to deal with the consequences of being known to have stolen a valuable artifact; in other words, he doesn’t to be a fugitive from the wizard police.
What happened to the Harry from Chapter 6?
A time turner is a superior to a healer’s kit in very nearly every way and by a huge margin. Yet all Harry does when he loses free access to his time turner he sulks a little and that’s all. He doesn’t plan at all! I don’t even recall one line of introspection on the subject! It takes very little ingenuity to to react:
“Harry, give me your time t...”
shit. shit. shit. Activate time turner. Escape. Then, he can spend five minutes and think up a dozen ways to retain time travel capability. Let me see...
Create a fake…
Lie to Hermione to get assistance?
Transfiguration not likely to work, given the teacher responsible.
assume that wizarding security is crap and guess (correctly) that he can probably steal one if needed...
actually leave Hogwarts because the time turner is more important and money can buy a better education anyway.
Ask Fred and George to discover a way for him to hide, to give him more time to plan.
Leave Hogwarts for a week.
Fill Gringots with silver.
Use money to buy a time turner on the black market
Also buy that hand-light that Malfoy bought.
And in general a stockpile of the most powerful and useful artifacts available.
And the best trunk that can be found anywhere or created for cash.
Return to Hogwarts if they will accept him after the week is up. (Or, for that matter, do it in the holidays. There isn’t that much of a rush.)
If circumstances demand, buy an education from one (or all) of the other schools.
Hire all the best tutors available for all subjects and use them to supplement school education with or without the cooperation of any teacher at the school, further insulating him from the ability of the teachers to f@#% with him or take his stuff.
Really… the best Harry can come up with is to say “that’s not fair”? WTF?
First, Harry discovered a gag beverage that he thought could be a key to power, although he quickly realized the Comed-Tea wasn’t as powerful as it seemed. A few days later he fell in love with a device that is sometimes given to students who want to take extra classes, although he has since discovered some limits to its powers. If he goes rogue over his Time-Turner’s crippleware, then who knows how much other cool and useful magical stuff he will miss out on, and how much trouble he’ll be in.
Plus, McGonagall had him cornered when she confronted him about returning the Time-Turner—whatever he tried to do, she’d see it. Also, McGonagall had earned some degree of trust & respect from Harry, she’s correct about Harry repeatedly misusing the Time-Turner, and she’d already warned him that they’d take it away. So it’s not unreasonable to go along with the punishment, and try to earn her trust back so that his Time-Turner can be restored later on.
...don’t take this the wrong way, but even Harry knows better than that.
If you genuinely think this is a smart thing to do in real life, it makes me seriously worry about your safety and the safety of people around you.
There is NO DOWN SIDE!
It may be best to hand over the time turner but you do so after having a chance to think it through. Time turner. Plan. Decide that it is better to hand over the device for now. Write your analysis down. Give it to yourself at the appropriate time. (And give it to yourself again to make the loop stable.)
I have offended you by questioning the rationality of your fictional persona. My own safety is not in any danger. Every other exceptional use that Harry put the device to is risky and I would not do any of them. But giving himself a chance to think through his options in a way that would not be detected by anyone else is the trivially correct strategic option.
My own safety is secure in the short term, and medium term (human life span) but for the long term the threats to my life are human mortality and existential risk. And that’s kind of what I’ve been counting on you to take care of (with any contribution that I could hope to make purely financial). That being the case, this conversation is quite literally scaring me. I’m not quite there yet, but the key quote from Snape is at least springing to my mind: “And I no longer trust your cunning.”
Examples of stupid things to do with a Time Turner:
Throw pies at people through misguided altruism. It would be better to let them break your finger. You’re at Hogwarts… a 5th year Luna could fix it.
Have a dramatic stand off over a rememberall. If it is so important… use the time turner to find and or steal the thing beforehand and leave it somewhere Neville will find. I mean seriously… using a time turner in a way that is detectable is for emergencies!
Disappearing acts from a class room. Of all the things to do with a Time Turner in that situation making a bigger scene is not one of them. At the very least, if you must refuse to be bullied, write yourself a note telling yourself to not attend potions and make another arrangement. It would be much easier to convince Dumbledore to allow Harry to hire potion tutors than have a full on confrontation.
Not using the time turner to go back and prevent the entire situation, after writing a great big essay to your past self on what happens if you mess with those in power.
Now, all the above mistakes are credible for Harry to make. At least, they fit the needs of the story. But using the turner to give yourself time to think at a critical moment… not on the list. And make no mistake, giving up one of the most powerful super-powers (even in the weakened 6h form) is an extremely critical moment.
But now another lesson from Harry Potter: MOR occurs to me: Always be sure you know exactly what you are both talking about. I may well be missing Eliezer’s real message.
What are we really talking about here? Being as EY may be several levels ahead of me the intended ‘this’ could be “implying that a respected authority is obviously wrong without a clear benefit to yourself”. That would make for extremely good advice, and a valid concern. Fortunately I for most part avoid that in real life. It does cost me and I do limit my options such that my environment doesn’t put me in that situation too often. One way to ensure my safety is to not put myself in situations that prompt risk taking. It isn’t optimal, except in the bounded sense, but it does work.
You seem to misunderstand how the time-turner works (or at least, how it’s been suggested it works). You don’t get to overwrite anything; the universe doesn’t “end up in” a stable state that results from using it; there isn’t any meta-time (or at least, we’ve seen nothing to suggest such). If he were going to use the time turner to give himself advice, he would have already gotten the advice. And having used the time-turner right there and visibly, he couldn’t use it “later not use it there” and have his going back in time undetectable.
A possible way he could use the time turner to help himself in this case would be to ask to go to the bathroom or somesuch, use the time turner, use the extra time to think, and then return to the room shortly after he left having thought about things.
(Edit: But this would be pretty obvious, and McGonagall probably wouldn’t let him leave the room with the time turner in any case.)
My interpretation of the “DO NOT MESS WITH TIME” incident was that you can try setting things up so that temporal consistency implies the result you want, but actually ruling out every other possibility whatever, including vast classes of outcomes you never even imagined, is next to impossible, at least for an 11-year-old boy, however smart. It hadn’t even occurred to him that there was a problem in his reasoning when he tried the experiment that gave him “the scariest result ever in the history of science”. Temporal consistency in the presence of time loops is another blind idiot god, far more swift and powerful than evolution.
Anyway, he still has the Time-Turner. All that stands between him and it is a magical lock. How difficult can that be for him to get around? No, actually what stands between him and it is the author’s necessity not to unbalance the plot by giving him a get-out-of-jail-free card.
Harry’s error in the experiment was responding to “DO NOT MESS WITH TIME” with the same. If he didn’t have the property of responding to that message with the same, that message wouldn’t appear.
Actually, this whole consistency-based time travel seems to be an extremely expressive thought experiment infrastructure for thinking about Newcomb-like problems and decision theories able to deal with them. Maybe I should do a top-level post on that (I don’t have a sufficiently clear picture of the setting, so I might be wrong about its potential)… Though I consider that happening unlikely, so other people who understand UDT are welcome to try.
I was thinking exactly the same thing. After getting my head around the implications it seems to be an extremely intuitive way of handling such problems. I didn’t write a post myself since I have yet to look close enough at UDT to be able to explain the difference between UDT and TDT.
I think you summed that up perfectly. I would have liked to see a little more of that explanation in the Fan Fic. It would make the story feel more natural and also be a perfect excuse to include the ‘blind idiot god’ kind of message.
Without Hermione backing him up? I think he’d struggle. Harry just isn’t that smart! He really should be spending more time sweet talking her. Well intentioned genius with ambition that doesn’t involve gaining power… just the kind of ally Harry needs.
Uh huh. It’s even worse than if Harry had actually gone and made himself rich on day 1!
He has been rich since day 1, it just that all his money is tied up in a variety of non-liquid “investments.”
I should say “insanely rich”, not merely ‘well off heir’.
Time travel in this universe has a consistent single line; once McGonagall sees Harry disappear, he can’t undo it.
Sounds like UDT might be applicable here. Here’s a time-traveling version of Counterfactual Mugging:
Harry appears to McGonagall and tells her, “If you give me 1 Galleon now, I’ll go back in time and hand you 100 Galleons an hour ago.” Suppose McGonagall does not recall being handed 100 Galleons an hour ago. What should she do?
Here’s my analysis. Suppose McGonagall decides not to give Harry 1 Galleon, then there are two possible consistent timelines for this universe. One where McGonagall gets 100 Galleons, and one where she doesn’t. How does the universe “choose” which one becomes reality? I don’t know but let’s say that the two possibilities have equal chance of being true, or get equal amount of “reality juice”.
Given the above it seems clear that McGonagall would prefer to have pre-committed to “give 1 Galleon even if not handed 100 Galleons an hour ago” since that would make the “not get 100 Galleons” timeline inconsistent. I think that’s also UDT’s output (although I haven’t written down the math to make sure).
ETA: I didn’t follow the previous discussion closely, so this might not apply at all to it. Hopefully, in that case the above is of interest in its own right. :)
Seems straightforward to me. McGonagall knows that she does not recall being handed 100 Galleons an hour ago, so the three states of the world with high probability are: 1) She is not in a universe where she will hand Harry 1 Galleon, 2) She is in a universe where she hands Harry 1 Galleon and Harry breaks the agreement, or 3) She is in a universe where she hands Harry 1 Galleon and Harry keeps the agreement in a way that leaves her unable to recall this happening. By not handing Harry a Galleon, she will ensure that she is in universe 1. By handing Harry a Galleon, she will find herself in universe 2 or 3. She should therefore give Harry a Galleon if she judges it less than 99 times more likely that Harry will break the agreement than fulfil it in a way consistent with her experience.
As Harry has access to a time machine, he doesn’t need to decide to give her 100 Galleons before he gets the 1 Galleon, so the situation is quite different to one based on predicting her actions, as Omega does in the Counterfactual Mugging. Rather it has most of the properties of the forward-time version of the gambit: “If you give me 1 Galleon now, I’ll hand you 100 Galleons in one hour”, except that McGonagall has a big piece of evidence that the promise will be broken, namely that she doesn’t remember it being kept.
Vladmir and I agree with the applicability of UDT and have suggested time-travel-with-consistency is a good way to consider Newcomblike problems and the the decision theories that can handle them.
Precommit, give him the Galleon, then reach in her bag to get the 100 Galleons. (She must have been Obliviated; otherwise, she would remember.)
You can actually get around a lot of the problems with time travel by taking advantage of the difference between observation and reality. For instance, if you see one of your friends die, you can go back in time, save him, then plant a fake double so you still have the same observations.
You can never know consistency, can never rely on it, otherwise you are inconsistent (2nd incompleteness theorem).
Though Godel was interested in time travel loops, that’s not the type of consistency that his Second Incompleteness Theorem discussed (it’s limited to formal axiomatized systems that can describe arithmetic).
I suspect Vladmir is considering the system in question here in a way that meets that description.
It seems we can’t rely on setups, which include decision making inside time loop, because it is not clear who or what makes decisions (agent? consistency law? agent’s preferences?).
All of the above. Decision making is just physics.
As I wrote earlier I am not yet convinced, that this is a kind of physics we can effectively reason of.
Consider correcting your claim to:
If you say ‘we’ you invite contradiction as your stance implies magical thinking about decision making which not many people would want to admit to. Decisions are not a special case. If gravity works you can build a gravity powered mechanical device that makes a decision.
Either you treat decisions exactly as you usually would or nothing works at all.
No. It’s not a decision making that is special. It is closed time loops. They possibly can “magically” create information from nothing.
Can I be in the one where the ‘created information’ is a a freak quantum conversion of graphite into diamond and not the one where the created information is freak quantum effects making my neurons fire in a way that they normally wouldn’t?
You can be there, no problem. The problem is to setup everyting to get there. I’ve just considered the question of setting up, and found that I can’t say even what causes existence of time loop. Can you say what should I do to be sure that no matter what after 1.01 hour I will timeturn 1 hour back? Being the person that will do that is important, but it will not help if in 20 minutes someone will steal my timeturner.
Returning back to 6(grand)parent, I can say, that imposing any condition on a stable state of time loop (but initial conditions before time loop) seems unphysical. All in all, thought experiments with time loops are interesting, but their validity is highly questionable.
Eliezer can do that, because he is consistency law of Harry’s universe.
Go think about it some more from the perspective of an integrated physics that happens to include time travel of this kind and not as a special case. That seems to be confusing you.
Eliezer can have Harry become a Hari Krishna if he really wants. Or he could artificially select for extremely improbable quantum events either inside or outside of time loops. Neither of those would make for an especially good story in this instance.
Ok. Almost pure physics.
A trolley is running out of control down a track. In its path are 5 people who have been tied to the track by a mad physicist. Fortunately, if trolley ran down different track, it would activate timeturner that would send it 10 seconds back in time and then trolly would flip a switch, which will lead the trolley down a different track to timeturner. And also a bystander runs to flip a switch.
Possible stable states.
Bystander stops and wait for trolley to appear from nowhere. Trolley kills 5.
Bystander stops and wait for trolley to appear from nowhere. Trolley appears from nowhere and flips the switch, then original trolley runs to timeturner and disappears.
Trolley appears from nowhere kills bystander, which almost managed to reach the switch, and flips the switch, then original trolley runs to timeturner and disappears.
Bystander appears from nowhere and flips the switch, then original bystander runs to timeturner and disappears. Trolley run past deactivated timeturner.
Bystander appears from nowhere shouts “watch your step!” and fails to flip switch in time, original bystander looks on timetraveller, missteps and falls, then manages to activate timeturner and disappears. Trolley kills 5.
Bystander appears from nowhere shouts “careful!” and flips switch, original bystander looks on timetraveller, missteps, but manages to not fall, then activates timeturner and disappears. Trolley run past deactivated timeturner.
Bystander appears from nowhere looks on trolley, shouts “damn! too late” and fails to flip switch in time, original bystander hearing that tries to run faster, missteps and falls, then activates timeturner and disappears. Trolley kills 5.
Bystander appears from nowhere, shouts “Shout, what I shouting now, it is very important!” and flips switch, original bystander activates timeturner and disappears. Trolley runs past deactivated timeturner.
Even in those rigid conditions stable states can be numerous without any improbable events. But yes, maybe you are right, because amount of information-from-nowhere must be limited by communication channel bandwidth (spoken or written speach, nonverbal actions of future-agent, agent’s memory throughput), thus rendering stable states in principle analyzable.
In a time loop do things still fall down? Is there gravity? And if I implement a decision making mechanism using a gravity powered system of gears and pulleys where is the magic thing that makes reason no longer apply?
Information from future will affect any kind of decision making. This information is a consequence of consistency law, it even doesn’t need to have cause.
Only because you termed that event “real”, but the characters can’t know that it is.
Is information in other minds what gets stabilized?
McGonagall went a fair way towards earning Harry’s respect, with her behavior about the med kit among other things; he is inclined to tolerate (with however much whining) her authority, particularly on school grounds.
Respect is all well and good… sure, maybe he will do some detention some time. But this is a matter of survival and something that can help him in a broad manner to achieve just about all his goals.
This is compared to Snape who.… said some things that might hurt Harry’s feelings.
Harry isn’t acting like a rationalist. He’s acting like a nerdy ape.
He’s eleven years old.
He is a week older than he was a week ago. So again I wonder what happened to the Harry from chapter 6?
I think he doesn’t want to become a criminal by stealing the Time Turner.
This doesn’t warrant one sentence worth of inner dialog? Seriously not buying it. It’s a different Harry hacked together for a different parable and as a plot hack to get rid of the Get Out Of Jail Free Card of Awesomeness +4.
He can’t have inner dialogue during that section, it’s in Minerva’s point of view!
That’s a good reason. So are you saying that Harry actually did do a thorough analysis of his optimal strategy for securing the benefits of time travel for “actually 5 minutes” at some stage but we just don’t hear about it? This would make the situation credible.
No, Harry’s experimental result scared the hell out of him and he decided not to do any more clever experiments until he was fifteen.
This is actually more rational than what you are advocating.
Are you sure you understand what I’m advocating? Your claim here suggests to me that you do not.
The most probable outcome of the thought process I outlined, and I say most probable because this is what my reasoning concluded but Harry is smarter than me, is that he will go and earn enough enough money to buy a time turner just in case. I aren’t advocating the use of the time turner to make reckless experiments or any of the non-authorized uses that Harry had previously used the device for. I actually made it quite clear what I thought of clever experimentation when explaining the note I would send myself. “Arrogant git” was the key phrase if I recall.
What kind of usage is sane? Emergency usage. For example, I would advocate the use of a time turner when locked in a room being tortured and at a high risk of suicide if I do not prevent it. (I liked the touch with the destroying all sharp objects too.) I would also advocate the use for saving lives (including his own depending on circumstances) with minimalist interventions, many of which would be not at all experimental given what he has already safely gotten away with. It would also be extremely valuable in the reduction of risk to have an extra 36 hours available for emergency use. Many threats to Harry’s world optimisation plans will come with some warning. Impending attack of some sort, etc. Having a turner on hand means that he would be able to take more time to make preparations or give th device to McGonnagal in the emergency situation and allow her to prepare. As far as either myself or Harry know she isn’t wise enough to have one on hand herself.
A time turner is a device that is massively useful and it is massively useful even if you use it conservatively and take no risks with it. Having one on hand does not make bad things happen unless you know you will be unable to control your foolish impulses. This is not Harry’s reasoning.
If Harry does not spend at least five minutes thinking through his priorities (let me emphasise that again, spend five minutes) and considering how to acquire (ie. buy) a time turner then both he and the author are making a big mistake. That is not* more rational. It is a rationalization of a decision that was originally made for the purposes of plot balance.
The reasonable solution is clearly for Harry to do is to put “buy time turner” down on his to do list right next to “become ridiculously rich in a week”. It is an obvious smart thing to do but the reader understands why Harry can’t really follow through with these plans for story purposes. Having them judged “not a pressing priority” is a credible explanation.
That’s a good answer.
Timeturner awesomeness for jail escape is pretty much discounted, when jailers know that one has it. And Harry risks being put under constant supervision because of his apparent disability of infancy.
It never occurred to me to consider it a literal way to escape from jails. That’s nearly useless. Instead, I consider it, among other things, as a nearly universally more effective med. kit. If someone just fell off the roof would you rather be able to bandage them up a bit or go back and tell them to watch their step?
… a good reason to not do things that are infantile… and when you do slip up you go back and give yourself a scolding so that you never do the infantile thing in the first place (but still give your past self the scolding note).
Good heavens, Mr. Wedrifid, you can’t change time! Do you think students would be allowed Time-Turners if that was possible? What if someone tried to change their test scores?
Good heavens Mr. Yudkowsky, I thought the inventor of Timeless Decision Theory would have a better grasp on how being the kind of person who would make a certain decision can determine what happens, even when that decision never needs to get made, whether that be with Omega and his boxes or in the stable resolution of time loops.
In all the previous time related events, things worked out how they did because the situation in which Harry did not use the time turner was not stable. If Harry was different (for example, by being Hermione or by not having a Time Turner) then the stable, ‘final version’ given by the universe-time-loop-processor would be the simple one where he doesn’t go mess with stuff. But it wasn’t.
But lets say that for some bizarre reason Harry never found a note warning him about a stumbling risk and he didn’t think to send one back later. At the very least we should find out a few seconds later that the friend fell off the building and landed on a great big padded mat.
I do indeed.
I’ve written unpublished fiction about it.
From before TDT was invented, actually.
Harry has not worked all that stuff out yet.
He did work out one important principle so far.
It is called DO NOT MESS WITH TIME.
And considering that he got that result, you seem to have missed some of the implications for how time travel works in that universe which would make it potentially dangerous to try and blackmail reality.
Time travel was the first optimization process I considered which was truly alien enough to deanthropomorphize my thinking; evolutionary biology didn’t do the job, but the unpublished story I was writing about time travel did.
What you’re suggesting is a bit more potentially incredibly dangerous than you seem to think.
I think you are mistaking me for straw-wedrifid here. I saw the problem with trying to blackmail reality before he went ahead and actually tried it. But then I’m not eleven and while I am arrogant I am not nearly as arrogant as Harry seems to be.
Exactly. To make certain situations impossible, you have to be the sort of person that makes the correct actions in the impossible situations, the actions making those situations impossible. (This is also at the core of bargaining.) You are not to take the money from two boxes in the Open Box Newcomb’s problem, even if you clearly see that money is there in both of them (and if you have that property, then the situation will never arise).
Harry tried “being the kind of person who would make a certain decision” when using the Time Turner. The result was DO NOT MESS WITH TIME.
He was trying to create a stable time loop, which had consequences along the same lines as the Outcome Pump—there’s no way to know which stable time loop you’ll get.
However, if he was using a “being the kind of person” strategy, we might expect he’d avoid being the sort of person who would pass along “DO NOT MESS WITH TIME”.
Yes, to repeat what I said earlier, this seems easy to avoid by replacing his “blank paper” condition with a more general “anything other than a pair of numbers in the given range” condition. I have to suppose Eliezer had him get that specific message because it wouldn’t be good for the story if Harry noticed this fact. Though even if he does take that approach, as with the outcome pump, there’s still other possibilities, because they can screw with Harry’s ability to execute his intended algorithm.
Yes, like it turning out that he was predetermined to die at the time of the experiment, and never complete it.
He did the same thing every time he used the time turner. I mean every time, even the times when he was being a good boy and using it to manage sleep. the universe doesn’t care whether it is a conversation with McGonnagal, juggling bullies and pies, someone falling off the roof or just bed time.
What does matter to the universe is whether the agent in the time loop is interacting with the time loop in a way that is complex and improbable. That is, factoring large primes should give unpredictable outcomes, long detailed tricks like throwing pies and playing with bullies should be slightly safer, giving yourself a time out simpler again and pre-sheduled study and sleep breaks right down at the bottom of the scale.
I argue that all the instance of time turner differ use differ only in degree. There are many things to do with a time turner that are far, far less disruptive, complex or unstable than what Hermione did when attending multiple classes. Given her interaction with other people who would be encountering her other self there are butterfly effects that would need to be resolved by the system. If Harry set up a smart system to communicate with himself unobtrusively things may be simpler to predict. He could send himself SMS messages (when outside Hogwarts) or use one of those coins to send messages.
This “scale” sounds extremely anthropomorphic.
An artifact of human language. The easiest way to describe most things (right down to basic forces) tends to be anthropomorphic.
As Eliezer said already, timeturner can’t change the past. One generally can’t even calculate probability of desired outcome of timeturning… Ouch. This is discussed already.
If anyone wants some sf on the subject, I recommend Leiber’s The Big Time and “Try and Change the Past”.
They’re both based on the same premise. The timeline is changeable but highly resistant. Humans can’t change it (that’s the short story) but there are two superhuman sides (called Snakes and Spiders, but never seen onstage) which recruit humans who are willing to be cut out of their timelines just before they die.
Probability is in the mind. It is the thing that is being calculated.
And the thing is “DO NOT MESS WITH TIME”.
That is a significant quote from the FanFic but I am having difficulty seeing it as relevant to Vladmir’s statement.
I found Vladimir’s utterance (I’m not sure of word’s connotations, I use it in pragmatics sense) incomprehensible on my current level of understanding his intentions and his ways of expressing toughts. So I’ve took literal meaning of his words into current context. However, beside joke part my message points on difficulties in dealing with stable states of closed time loops (the thing).
This is not an unusual occurrence. V thinks clearly, and thoroughly but presents his conclusions in a way that assumes a similar thinking style and a lot of shared prior knowledge. Petty things like ‘intermediate steps’ are not necessarily included.
I disagree with this statement. See earlier discussion of ‘idiot god’ by Richard.
Those closed time loops are weird. I considered timeturing before outcome, but, yes, even in that case one can be told by one’s timeturned twin, that all is set up for good outcome. And timeturing after desired outcome… should be done unconditionally, as you can’t know it is not you who caused this outcome. Weird.
Definitely weird. A related consideration is that I would always give reasons for any advice I give my former self. That cuts off a large swath of potential stable loops that consist of me giving myself advice for absolutely no reason at all except that it happens to be stable. The better the reasons I have been given myself the less likely it is that the self perpetuating cycle is a completely arbitrary cycle.
For example, I wouldn’t have sent back “Don’t mess with time”. I would have sent “the universe doesn’t particularly care about your rules and plans you arrogant little git! What’s more likely, guessing your way through 128 bit encryption or something seriously nasty that distracts you from your games, such as ? That’s right. Think.” (Yes, I’d include the ‘arrogant git’ part. That is information I would clearly need to be reminded of!)
Now, not all scary situations give me the chance to write an explanation but a large swath of the probability mass does. While I would still follow the hastily written directive I would also know that to write that particularly message something really bad must be happening. Without having a predetermined policy for giving details I would have no idea whether the message meant something bad almost happened or not. (It also means that I am far less likely to get such a message—I’ll probably get one of the many possible detailed messages.)
The problem is that you aren’t source of advice, you are one of constraints to be satisfied. Any message, that you will reproduce with picometer precision and that will create stable state, will do. Precision isn’t a problem in deterministic world, and maybe in quantum one too (if our neurons are sufficiently classical), but I’m hesitant to estimate influence of one’s preferences on stable state.
I am both. The advice that I will choose to give is determined by the same physics that allows me to breath.
Regarding quantum effects—the uncertainty effects can be amplified based on the elimination of unstable loops. Most obviously when my behavior is determined by a quantum coin. The way that plays out looks seriously when pictured in 4 dimensions.
Not necessarily.
Self-existing objects and auto-generated information in chronology-violating space-times: A philosophical discussion
I read the link and make the same claim I made previously: I am both. The advice that I will choose to give is determined by the same physics that allows me to breath.
Wait a second, you will not choose an advice. You will reproduce the advice (consistency constraint!).
And for the advice to be advice you choose, it must be physically impossible to you to reproduce anything you think is not of your origin. I envy your self-esteem.
Edit: Given condition is sufficient, but not necessary.
You don’t have to reproduce the advice. And if you don’t, you won’t have to.
That is important special case: the advice = no advice. But that is easy to overlook, thanks.
Well, you’ve convinced me.
I guess you could argue that it wasn’t criminal to do so, but he had no qualms about stealing gold from his bank vault.
I mean that he doesn’t want to deal with the consequences of being known to have stolen a valuable artifact; in other words, he doesn’t to be a fugitive from the wizard police.