Assume you have all the luxuries of a modern life in your Tardis (toilet, hot showers, TV, books, game console, …) which doubles as a mini self-sufficient apartment with it’s own energy stores and generation.
Where in history would you go if comfort wasn’t an issue?
The end of time and the edge of the universe to have a good meal at the restaurant.
It might just be a bistro
i’d go to the first nuclear bomb test, after it went off i’d say they just created a rift in time, and i came back to stop them from destroying the world through paradoxes….
Just make sure you don’t accidentally become your own grandparent.
Put on fake ears and paint yourself green
Lol shit
The middle of the carboniferous, imagine forests growing for millions of years and wood not decaying. There should be mountains made of wood.
I’ve got a mountain made of wood…in my pants
Go back to before multicellular life evolved so nothing will bother me
No air
Lol gotcha
I’d go watch the pyramids being built, should be very interesting.
That’d take a long time unless you skip ahead a few years every now and then
I’ll visit past me and leave some letters that contain useful information. You know, don’t trust those people, avoid doing this mistake, know yourself etc. would be interesting to see how that timeline diverges from my own.
Actually. now that I’ve opened this door, might as well try influencing world history on a larger scale. How about I visit certain key moments where a dangerous person almost died, but survived to cause massive harm later down the line. Would be really interesting to see how history plays out after nudging Hitler a little bit closer than to that suitcase. History is just full of special moments like that.
I wouldn’t be a passive observer. I would actively change things to see what happens.
BTW, I believe in the many words interpretation of quantum physics, so all possibilities are equally real and they all exist simultaneously. No matter how hard you try to fix things or how badly you mess things up, that disaster branch was already there, always will be.
If you like fiction (and Stephen King for that matter), you should read 11 22 63. Main character goes back in time to change past events and things… sort of work out. It has a cool take on time travel and course of events in general, I was a big fan of reading it.
There is also a mediocre tv adaption of it as well if you’re not into fiction, but I didn’t finish it.
Some other books that handle time travel in fun ways and play with explicitly making changes to the past.
- Asimov’s The End of Eternity (might have gone without saying)
- Jack Finney’s Time and Again (read it as a kid, so might not actually be that good, but it’s illustrated which is fun!)
Many Worlds is an incredibly bizarre point of view.
Quantum mechanics has two fundamental postulates, that being the Schrodinger equation and the Born rule. It’s impossible to get rid of the Born rule in quantum mechanics as shown by Gleason’s Theorem, it’s an inevitable consequence of the structure of the theory. But Schrodinger’s equation implies that systems can undergo unitary evolution in certain contexts, whereas the Born rule implies systems can undergo non-unitary evolution in other contexts.
If we just take this as true at face value, then it means the wave function is not fundamental because it can only model unitary evolution, hence why you need the measurement update hack to skip over non-unitary transformations. It is only a convenient shorthand for when you are solely dealing with unitary evolution. The density matrix is then more fundamental because it is a complete description which can model both unitary and non-unitary transformations without the need for measurement update, “collapse,” and does so continuously and linearly.
However, MWI proponents have a weird unexplained bias against the Born rule and love for unitary evolution, so they insist the Born rule must actually just be due to some error in measurement, and that everything actually evolves unitarily. This is trivially false if you just take quantum mechanics at face value. The mathematics at face value unequivocally tells you that both kinds of evolution can occur under different contexts.
MWI tries to escape this by pointing out that because it’s contextual, i.e. “perspectival,” you can imagine a kind of universal perspective where everything is unitary. For example, in the Wigner’s friend scenario, for his friend, he would describe the particle undergoing non-unitary evolution, but for Wigner, he would describe the system as still unitary from his “outside” perspective. Hence, you can imagine a cosmic, godlike perspective outside of everything, and from it, everything would always remain unitary.
The problem with this is Hilbert space isn’t a background space like Minkowski space where you can apply a perspective transformation to something independent of any physical object, which is possible with background spaces because they are defined independently of the relevant objects. Hilbert space is a constructed space which is defined dependently upon the relevant objects. Two different objects described with two different wave functions would be elements of different Hilbert spaces.
That means perspective transformations are only possible to the perspective of other objects within your defined Hilbert space, you cannot adopt a “view from nowhere” like you can with a background space, so there is just nothing in the mathematics of quantum mechanics that could ever allow you to mathematically derive this cosmic perspective of the universal wave function. You could not even define it, because, again, a Hilbert space is defined in terms of the objects it contains, and so a Hilbert space containing the whole universe would require knowing the whole universe to even define it.
The issue is that this “universal wave function” is neither mathematically definable nor derivable, so it only has to be postulated, as well as its mathematical properties postulates, as a matter of fiat. Every single paper on MWI ever just postulates it entirely by fiat and defines by fiat what its mathematical properties are. Because the Born rule is inevitable form the logical structure of quantum theory, these mathematical properties always include something basically just the same as the Born rule but in a more roundabout fashion.
None of this plays any empirical role in the real world. The only point of the universal wave function is so that whenever you perceive non-unitary evolution, you can clasp your hands together and pray, “I know from the viewpoint of the great universal wave function above that is watching over us all, it is still unitary!” If you believe this, it still doesn’t play any role in how you would carry out quantum mechanics, because you don’t have access to it, so you still have to treat it as if from your perspective it’s non-unitary.
Thanks for the in-depth explanation.
The way I see it, MWI is more of a philosophical idea. As far as I know, it’s impossible to test it, so currently it’s still firmly outside the sphere of science.
You pointed out some valid reasons why the future of MWI looks shaky, and I’m fine with that. If MWI falls apart, I’ll just move on to the next best thing. I just find MWI intuitively appealing, but I don’t have any strong reasons to believe it or reject it. As you mentioned, MWI doesn’t change the way you would carry out quantum mechanics, so currently it has no practical impact.
I would give John Hinckley Jr some shooting lessons.
Exactly! That’s the sort of time travel I’m talking about!
Next stop: 1095, the office of Alexios I Komnenos. Who wants to see what the world looks like without the crusades?
I wouldn’t mind being there at the end of the children’s crusade, at the edge of the Mediterranean, as scores of kids wait for it to part. I’d just be there with a table and a chair, selling them Yo-yos
Bring some ice cream too. Those kids will never be the same after that.
Bring him back to the future with you
No need, he’s still alive and making youtube videos lol https://www.youtube.com/watch?v=U4Lr5zMgE08
I’ve given this a lot of thought but I’d love to meet oppressed historical figures. I’d love to see people autonomously standing up for themselves like at Stonewall and The Battle of Cable Street. I assume that they are both more brutal than anything I can imagine but it blows my mind to realize how many people came together.
I’d love to see the parts of town where the post-WW2 “slum clearings” took place. Gentrification is having a real impact here at the moment and its a shame. We recently lost a shabby 80s community centre and the building that replaced it never got the community back. Honestly, I just want to walk around here before the cars arrived.
A stranger thing that I would want to see is the old wood-paneled stock on the Metropolitan line of the London Underground in service at its peak. I generally would just want to explore transport systems as a whole. Getting to ride a 1910s tram on the street would probably feel surreal.
Oh WW2 London is a fave of mine. I’ve always wondered what the slums of Deptford looked like. Right now it’s an overly gentrified rich person’s suburbia, but back then it was the rotted lungs of the shipping industry. It would be also nice to know what it was like hiding out in the tube with a bunch of strangers. Did anyone play music? Was there singing above the praying? Did people trade books and cigarettes?
…A bit of a non-chill reply here, but apparently Unreal Engine can complete that wish.
Like, there was this captain America game set in 1943 Germany written by, I think, Uncharted’s writer, that was presented at State Of Unreal 2024. It looks insanely real and you can like, feel smoke in a burning barrel and all, so London could be modelled there as well.
State Of Unreal 2024
https://www.youtube.com/live/Z_DssjLeGa0&t=1162
Looks half decent, I’d love it to be a Assassin’s Creed Style open world set in WW2 London
first things first.
i would relax in my new Tardis, with all the needed luxuries, and take that in for a while. take care of me
“what would you do if your basic needs were met?”
“chill the fuck out”seems like a solid answer to me no joke
I would stop my kid self from taking the concerta I was prescribed and instead get him to drink a cup of coffee every morning, and would also give him advice for when he stops being a Christian and his parents go apeshit and try to desperately bring him back into the fold.
Also I would prefer to use a DeLorean
I genuinely think I fixed my ADHD with coffee. I know exactly how dumb that sounds, but I genuinely think it’s true. Sorry about your shitty parents. Hope they had their good moments.
Having both autism and ADHD, Concerta overstimulated me way too much. Kids probably shouldn’t be taking Concerta anyway
It’s not dumb, stimulants are stimulants.
Hard stimulants like Concerta and Adderall are better more for pure ADHD than for Autism+ADHD like I have. Anything stronger than caffeine overstimulates me too much, I wish I didn’t go years before realizing I was better off without it
Absolutely nowhere. I’ll spend rest of my life enjoying myself in the tardis.
Go back to various ancient cities and just sit in the equivalent of the town square and watch a day go by. See the food! So many lost recipes. See the clothing??? We only know what the wealthy wore for the most part, I want to see what the majority of people ate, drank, wore, what their homes looked like. What did they do to pass the time??
right? walk a mile in the average person’s footsteps.
Though I’m now imagining some weird guy bursting into my house in strange garb, just as I’m about to go to work, excitedly pointing at my vacuum cleaner, and the bills on my table, and exclaiming “this is brilliant!”
Haha, I’d ask! If it’s a tardis, it should be translating and making me look like I fit in, yeah? At least clothing wise. I’d be a pale weirdo in a lot of places, but it should work! I’ll ask if I can visit, and bring them…wine works, right? That’s pretty ancient and won’t raise questions. That I’d answer with “it’s a gift from far awaaaaaaay” very awkwardly.
*Teleports into the middle of the Black Plague. Starts handing out lifesaving antibiotics in plastic pop pill sachets*
“Uhhh, a normal product from the East… yes…”
“Take care” of Christopher Columbus.
Possibly Ghengis Khan too. And a handful of Roman Emperors and European royalty.
Give all the natives AK-47s and tons of ammo
Ah yeah, spa treatments work wonders. I often wonder what path Hitler would have taken if he had a decent steam room, instead of all those amphetamines he was taking…
I would probably look at a few interesting years I am aware of, but after a while I figure it would devolve into “I dunno man, what the fuck was going on in 1111?”
Or 1337?
I’d love to see the future, because I really am hopeful for humanity to move beyond all this bullshit to some post scarcity utopia :)) Failing that, I’d probably go watch Phineas Gage’s big moment, because, woah.
I don’t think you’d want to go into the future after the point time travel was invented because then other time travellers will have been messing with the timeline back and forth a million ways.
I’d love to witness the Chixilub impact. Or Pompeii, or any huge natural disaster. The bigger the better. I’d also like to figure out how the moon was actually created. Then see the sun swallow the earth at the end.
Those last two might require some careful planning on where to be to witness those events safely
