Canon itself agrees that the canon risk is exaggerated; Harry and Herminone did see their past selves, and Harry even saw his future self (but thought that it was his father). Nothing bad happened.
However, the canon warning can be justified: If you attempt to change what you remember from your past, then the time-consistency force will stop your contradiction, and that can be dangerous. If the easiest way to enforce consistency is to mess with your memories, it just might drive you mad!
All this is trivially circumvented. Remember those instruments Dumbledore regretted inspecting? Well, just build a backdoor into them to modify their readings, and make sure that you’re the only one that the backdoor lets through. Messing with sensory input is less dangerous than messing with the mind. Can’t use rely on some vague instruments when you are an active participant of events? What about plain old glasses or a mask? Can’t unsee your future self? Well, as long as your previous self knows that your future self is able to make glasses show you anything they wish, you’re free not to believe your eyes. Might throw an extra hallucination once in a while just to make sure. Plausible deniability FTW!
If you attempt to change what you remember from your past, then the time-consistency force will stop your contradiction, and that can be dangerous. If the easiest way to enforce consistency is to mess with your memories, it just might drive you mad!
The force isn’t so simple. While the time turner use will increase the prevalence of a stable loop involving distorted memories this is far from the easiest way for a stable loop to result. It is far more likely to ensure that the world of which you are a part to not to have ever existed, with the measure diverted to the possible stable loop that is the result of iterating from the effects of your new interference.
The way I use the word ‘exist’, the world that I’m a part of necessarily exists. In any case, it’s the only world that I care about.
All this stuff about iterating unstable loops to a stable limit (assuming that one even exists) can be a good way to think about time travel from the outside, but that can’t be how it appears to the people on the inside. (The world isn’t going to notice that I’m a mind with a right to existence and change around me while preserving my unusual memories, despite what Doc Brown told Marty would happen to Jennifer in Back to the Future II.)
but that can’t be how it appears to the people on the inside.
Potential nightmare fuel ahead. ROT13′d for your sanity.
Jung vg ybbxf yvxr sebz vafvqr: Uneel jvyy bcra gur cncre, svaq gjb ahzoref gung qba’g zhygvcyl gb gur cevzr, naq nggrzcg gb pnhfr n cnenqbk ol fraqvat onpx n qvssrerag cvrpr bs vasbezngvba.
Abj, Uneel vf qrafr ng gvzrf. Ur xarj guvf jnf ‘hafgnoyr’ nppbeqvat gb ZpTbantnyy, gung vg jnf nyy cerpnyphyngrq naq gung lbh pna’g punatr nal vasbezngvba. Ur fghqvrq sbe bar ubhe naq gura sbyybjrq guebhtu jvgu uvf pbhefr bs npgvba, naq bapr ur unf zvffrq uvf nofbyhgr ynfg punapr ng punatvat gur cncre, Uneel naq guvf cnegvphyne ybbc bs gur havirefr oyvffshyyl prnfr gb unir rire rkvfgrq, qhr gb pbagnvavat n cnenqbk.
Abj, Uneel vf n fzneg xvq. Ur cebonoyl unf fbzr vqrn bs ubj dhnaghz vzzbegnyvgl jbexf, fb ur rkcrpgf gb or va gur fgnoyr ybbc gunaxf gb “cnenqbk vzzbegnyvgl”. Qhevat uvf fghqlvat, ur nofrag-zvaqrqyl erzrzoref naq zhygvcyvrf gur gjb arj ahzoref ur jebgr qbja, naq frrf gung gurl, gbb, nera’g gur snpgbef bs gur cevzr. Ur ortvaf gb jbeel. Vs, rira jvgu gur cbjre bs vzzbegnyvgl ba uvf fvqr, ur vf fgvyy va na hafgnoyr ybbc, gung zhfg zrna gurer ner bayl hafgnoyr ybbcf. Ur vafgnagyl ertergf abg gevcyr-purpxvat Greel’f jbex jvgu fbzrbar ryfr! Jung vs Greel unf n flfgrzvp synj va uvf zhygvcyvpngvba fxvyyf? Ol erylvat fbyryl ba Greel, ur unf dhvgr cbffvoyl pnhfrq uvzfrys gb jvax bhg bs rkvfgrapr ragveryl, genccvat rirel irefvba bs uvzfrys va na hafgnoyr ybbc gung vf irel fubegyl nobhg gb raq. CBGGRE, LBH CEVPX!
Abj, Uneel vf n ernyyl fzneg xvq. Ur jvyy nyzbfg pregnvayl or guvaxvat nobhg nyy gur vasbezngvba ur xabjf nobhg Gvzrghearef. Vg jba’g gnxr zhpu vqyr gubhtug sbe gur zrzbel
naq vg jvyy bpphe gb uvz gung lbh pna qryrgr nyy gur crbcyr nssrpgrq, lbh pna punatr gvzr, vg’f whfg gung abobql rire svaqf gung bhg, orpnhfr gurl unir nyy orra yvivat va n fgnoyr ybbc. Naguebcvp ovnf, ohg abg va gur jnl ur rkcrpgrq. Boivbhfyl, gur punaprf bs cebqhpvat n fgnoyr ybbc va bar tb ner ybj, ohg n ybat frevrf bs urnqf qbrfa’g zrna gur arkg bar pna’g or gnvyf. Uneel xabjf gung.
Naq abj ur xabjf gung uvf sbezvqnoyr vagryyrpg jnf nccyvrq gb ratvarrevat n fvghngvba gung sbeprf Gvzr vagb vafgnovyvgl, naq va qbvat fb dhvgr cbffvoyl qrfgeblf gur jubyr havirefr, fgnoyr naq hafgnoyr ybbcf or qnzarq. Fb abj ur unf bhgjvg uvf cerivbhf frys. Ur pna’g punatr gur cncre onpx gb gur bevtvany ahzoref, orpnhfr gura gur arkg Uneel gb pbzr nybat jbhyq punatr vg, naq vg jnf bayl enaqbz svevat bs arhebaf gung cebqhprq gung cnegvphyne pbaarpgvba, gur Gvzrgheare zvtug abg unir gur erfbyhgvba gb cebqhpr gur rknpg fnzr cnggrea, gur arkg Uneel zvtug abg ernyvfr ur vf nobhg gb qrfgebl nyy bs rkvfgrapr -
Znal irefvbaf bs Uneel ernyvfr guvf, naq senagvpnyyl frg nobhg nggrzcgvat gb snpgbe gur cevzr ol unaq va haqre na ubhe, jvgu gur jubyr bs rkvfgrapr evqvat ba vg, gvzr vf ehaavat qbja, ur’f fpevooyvat znqyl, ur’f abg tbvat gb znxr vg, ur’f qrfgeblrq gur ragver havirefr!-
Bayl n srj irefvbaf bs Uneel jbhyq ernyvfr, ng fbzr cbvag qhevat gur znq fpenzoyr gb zhygvcyl snfgre, gung “QB ABG ZRFF JVGU GVZR” jbhyq jbex. Gurfr irefvbaf jbhyq jevgr gung qbja, gura fcraq gur erfg bs gur gvzr fcrphyngvat ba ubj znal oenapurf bs uvzfrys qba’g guvax bs gur “QB ABG ZRFF JVGU GVZR” zrffntr.
Bayl bar irefvba bs Uneel jbhyq trg gur “QB ABG ZRFF JVGU GVZR” zrffntr gb ortva jvgu. Ur zvtug guvax vg jnf gur fpnevrfg rkcrevzragny erfhyg va uvfgbel, ohg ur’f abg rira pybfr. Rirel bgure irefvba bs uvz jbhyq cbvag bhg gung gurve erfhyg vf beqref bs zntavghqrf zber greevslvat.
That’s a great description, but it’s not from the inside of reality. I mean, if I experience something (such as multiplying two numbers and getting the wrong answer), then it exists, pretty much by definition. (Even if I’m hallucinating, the hallucination exists.) To some extent, this is a matter of semantics, but if my usage of ‘exists’, ‘real’, etc are to match ordinary language, then they have to come out this way. Within the fictional story, I use the viewpoint character instead of myself, so if Harry experiences something (while he’s the viewpoint character), then it’s real within the story.
However, I catch your reference to Greg Egan’s Permutation City. (If you made a reference to anything else, then I missed it.) So there is a flaw in my reasoning here: I’m assuming that everything that we see in MoR is from within a single consistent (albeit fictional) history, just as in the canonical books. But that might not be so! We could be seeing things from within various unstable loops (somewhat as in PC, although there the instability wasn’t a matter of looping), even though the canonical books only showed us stable loops. Since EY (like Egan) accepts the many-worlds interpretation of quantum mechanics (even though not of probability), it’s only more likely that he would do something like this. On the other hand, we haven’t so far seen anything that directly suggests this.
I’m assuming that everything that we see in MoR is from within a single consistent (albeit fictional) history
I agree with this assumption: that’s why MoR only shows you the consistent history of the usage of Timeturners. The Timeturner itself is the only point of possible divergence from consistent history (assuming no magic lets us mess with causality, although it seems like Weasley’s “opposite reaction wards” at least have a chance), and EY is writing a story about a rationalist Harry Potter, not a story about wizards using Timeturners, so he won’t bother to show all the inconsistent histories.
And “inconsistent histories” from the perspective of a consistent history is a contradiction in terms; it is no wonder it clashes with the meanings of real, exists, and so forth.
All this stuff about iterating unstable loops to a stable limit (assuming that one even exists) can be a good way to think about time travel from the outside, but that can’t be how it appears to the people on the inside.
Harry, for example, already sees ‘reality’ as a quantum waveform. He is not limited to naive models of the world. “Iteration to stable loops” isn’t a concept that is particularly important when considering time travel of the kind in evidence in HP and in the presence of a complete physics that does include quantum mechanics.
“My brain will be hacked” is not actually the most simple or likely outcome except in the sense of “narrative simplicity given naive author”.
Canon itself agrees that the canon risk is exaggerated; Harry and Herminone did see their past selves, and Harry even saw his future self (but thought that it was his father). Nothing bad happened.
However, the canon warning can be justified: If you attempt to change what you remember from your past, then the time-consistency force will stop your contradiction, and that can be dangerous. If the easiest way to enforce consistency is to mess with your memories, it just might drive you mad!
All this is trivially circumvented. Remember those instruments Dumbledore regretted inspecting? Well, just build a backdoor into them to modify their readings, and make sure that you’re the only one that the backdoor lets through. Messing with sensory input is less dangerous than messing with the mind. Can’t use rely on some vague instruments when you are an active participant of events? What about plain old glasses or a mask? Can’t unsee your future self? Well, as long as your previous self knows that your future self is able to make glasses show you anything they wish, you’re free not to believe your eyes. Might throw an extra hallucination once in a while just to make sure. Plausible deniability FTW!
The force isn’t so simple. While the time turner use will increase the prevalence of a stable loop involving distorted memories this is far from the easiest way for a stable loop to result. It is far more likely to ensure that the world of which you are a part to not to have ever existed, with the measure diverted to the possible stable loop that is the result of iterating from the effects of your new interference.
The way I use the word ‘exist’, the world that I’m a part of necessarily exists. In any case, it’s the only world that I care about.
All this stuff about iterating unstable loops to a stable limit (assuming that one even exists) can be a good way to think about time travel from the outside, but that can’t be how it appears to the people on the inside. (The world isn’t going to notice that I’m a mind with a right to existence and change around me while preserving my unusual memories, despite what Doc Brown told Marty would happen to Jennifer in Back to the Future II.)
Potential nightmare fuel ahead. ROT13′d for your sanity.
Jung vg ybbxf yvxr sebz vafvqr: Uneel jvyy bcra gur cncre, svaq gjb ahzoref gung qba’g zhygvcyl gb gur cevzr, naq nggrzcg gb pnhfr n cnenqbk ol fraqvat onpx n qvssrerag cvrpr bs vasbezngvba.
Abj, Uneel vf qrafr ng gvzrf. Ur xarj guvf jnf ‘hafgnoyr’ nppbeqvat gb ZpTbantnyy, gung vg jnf nyy cerpnyphyngrq naq gung lbh pna’g punatr nal vasbezngvba. Ur fghqvrq sbe bar ubhe naq gura sbyybjrq guebhtu jvgu uvf pbhefr bs npgvba, naq bapr ur unf zvffrq uvf nofbyhgr ynfg punapr ng punatvat gur cncre, Uneel naq guvf cnegvphyne ybbc bs gur havirefr oyvffshyyl prnfr gb unir rire rkvfgrq, qhr gb pbagnvavat n cnenqbk.
Abj, Uneel vf n fzneg xvq. Ur cebonoyl unf fbzr vqrn bs ubj dhnaghz vzzbegnyvgl jbexf, fb ur rkcrpgf gb or va gur fgnoyr ybbc gunaxf gb “cnenqbk vzzbegnyvgl”. Qhevat uvf fghqlvat, ur nofrag-zvaqrqyl erzrzoref naq zhygvcyvrf gur gjb arj ahzoref ur jebgr qbja, naq frrf gung gurl, gbb, nera’g gur snpgbef bs gur cevzr. Ur ortvaf gb jbeel. Vs, rira jvgu gur cbjre bs vzzbegnyvgl ba uvf fvqr, ur vf fgvyy va na hafgnoyr ybbc, gung zhfg zrna gurer ner bayl hafgnoyr ybbcf. Ur vafgnagyl ertergf abg gevcyr-purpxvat Greel’f jbex jvgu fbzrbar ryfr! Jung vs Greel unf n flfgrzvp synj va uvf zhygvcyvpngvba fxvyyf? Ol erylvat fbyryl ba Greel, ur unf dhvgr cbffvoyl pnhfrq uvzfrys gb jvax bhg bs rkvfgrapr ragveryl, genccvat rirel irefvba bs uvzfrys va na hafgnoyr ybbc gung vf irel fubegyl nobhg gb raq. CBGGRE, LBH CEVPX!
Abj, Uneel vf n ernyyl fzneg xvq. Ur jvyy nyzbfg pregnvayl or guvaxvat nobhg nyy gur vasbezngvba ur xabjf nobhg Gvzrghearef. Vg jba’g gnxr zhpu vqyr gubhtug sbe gur zrzbel
“juvpu jbhyq cerggl zhpu QRYRGR NYY GUR CRBCYR NSSRPGRQ”—“Bu, lbh pna’g punatr gvzr!”
gb pbaarpg gb gur ernfbavat oruvaq
Vs lbh qvq pbzzvg gur cresrpg pevzr, abobql jbhyq rire svaq bhg—fb ubj pbhyq nalbar cbffvoyl xabj gung gurer jrera’g cresrpg pevzrf?
naq vg jvyy bpphe gb uvz gung lbh pna qryrgr nyy gur crbcyr nssrpgrq, lbh pna punatr gvzr, vg’f whfg gung abobql rire svaqf gung bhg, orpnhfr gurl unir nyy orra yvivat va n fgnoyr ybbc. Naguebcvp ovnf, ohg abg va gur jnl ur rkcrpgrq. Boivbhfyl, gur punaprf bs cebqhpvat n fgnoyr ybbc va bar tb ner ybj, ohg n ybat frevrf bs urnqf qbrfa’g zrna gur arkg bar pna’g or gnvyf. Uneel xabjf gung.
Naq abj ur xabjf gung uvf sbezvqnoyr vagryyrpg jnf nccyvrq gb ratvarrevat n fvghngvba gung sbeprf Gvzr vagb vafgnovyvgl, naq va qbvat fb dhvgr cbffvoyl qrfgeblf gur jubyr havirefr, fgnoyr naq hafgnoyr ybbcf or qnzarq. Fb abj ur unf bhgjvg uvf cerivbhf frys. Ur pna’g punatr gur cncre onpx gb gur bevtvany ahzoref, orpnhfr gura gur arkg Uneel gb pbzr nybat jbhyq punatr vg, naq vg jnf bayl enaqbz svevat bs arhebaf gung cebqhprq gung cnegvphyne pbaarpgvba, gur Gvzrgheare zvtug abg unir gur erfbyhgvba gb cebqhpr gur rknpg fnzr cnggrea, gur arkg Uneel zvtug abg ernyvfr ur vf nobhg gb qrfgebl nyy bs rkvfgrapr -
Znal irefvbaf bs Uneel ernyvfr guvf, naq senagvpnyyl frg nobhg nggrzcgvat gb snpgbe gur cevzr ol unaq va haqre na ubhe, jvgu gur jubyr bs rkvfgrapr evqvat ba vg, gvzr vf ehaavat qbja, ur’f fpevooyvat znqyl, ur’f abg tbvat gb znxr vg, ur’f qrfgeblrq gur ragver havirefr!-
Bayl n srj irefvbaf bs Uneel jbhyq ernyvfr, ng fbzr cbvag qhevat gur znq fpenzoyr gb zhygvcyl snfgre, gung “QB ABG ZRFF JVGU GVZR” jbhyq jbex. Gurfr irefvbaf jbhyq jevgr gung qbja, gura fcraq gur erfg bs gur gvzr fcrphyngvat ba ubj znal oenapurf bs uvzfrys qba’g guvax bs gur “QB ABG ZRFF JVGU GVZR” zrffntr.
Bayl bar irefvba bs Uneel jbhyq trg gur “QB ABG ZRFF JVGU GVZR” zrffntr gb ortva jvgu. Ur zvtug guvax vg jnf gur fpnevrfg rkcrevzragny erfhyg va uvfgbel, ohg ur’f abg rira pybfr. Rirel bgure irefvba bs uvz jbhyq cbvag bhg gung gurve erfhyg vf beqref bs zntavghqrf zber greevslvat.
That’s a great description, but it’s not from the inside of reality. I mean, if I experience something (such as multiplying two numbers and getting the wrong answer), then it exists, pretty much by definition. (Even if I’m hallucinating, the hallucination exists.) To some extent, this is a matter of semantics, but if my usage of ‘exists’, ‘real’, etc are to match ordinary language, then they have to come out this way. Within the fictional story, I use the viewpoint character instead of myself, so if Harry experiences something (while he’s the viewpoint character), then it’s real within the story.
However, I catch your reference to Greg Egan’s Permutation City. (If you made a reference to anything else, then I missed it.) So there is a flaw in my reasoning here: I’m assuming that everything that we see in MoR is from within a single consistent (albeit fictional) history, just as in the canonical books. But that might not be so! We could be seeing things from within various unstable loops (somewhat as in PC, although there the instability wasn’t a matter of looping), even though the canonical books only showed us stable loops. Since EY (like Egan) accepts the many-worlds interpretation of quantum mechanics (even though not of probability), it’s only more likely that he would do something like this. On the other hand, we haven’t so far seen anything that directly suggests this.
Omake files? :P
I agree with this assumption: that’s why MoR only shows you the consistent history of the usage of Timeturners. The Timeturner itself is the only point of possible divergence from consistent history (assuming no magic lets us mess with causality, although it seems like Weasley’s “opposite reaction wards” at least have a chance), and EY is writing a story about a rationalist Harry Potter, not a story about wizards using Timeturners, so he won’t bother to show all the inconsistent histories.
And “inconsistent histories” from the perspective of a consistent history is a contradiction in terms; it is no wonder it clashes with the meanings of real, exists, and so forth.
Oh boy.
Harry, for example, already sees ‘reality’ as a quantum waveform. He is not limited to naive models of the world. “Iteration to stable loops” isn’t a concept that is particularly important when considering time travel of the kind in evidence in HP and in the presence of a complete physics that does include quantum mechanics.
“My brain will be hacked” is not actually the most simple or likely outcome except in the sense of “narrative simplicity given naive author”.