Do You Exist In Infinite Universes? | Answers With Joe

this video is supported by Skillshare as many of you know I grew up in Texas and you know about this because I talk about it kind of a lot how do you know someone's from Texas just wait they'll tell you Texans are basically country vegans anyway growing up my grandparents had a ranch out in near Abilene Texas and it probably is not a surprise to you to hear that there were guns around I'm not really a gun guy these days but I definitely grew up around guns and if you're wondering why I'm talking about guns in a quantum physics video it's because hey that never splits a crowd actually it's because one of those guns almost killed me you know you don't need the sound it's it's dramatic enough but at one point we were out at the tank the tank is like a man-made pond a little reservoir where the cows come and drink and stuff like that but my cousin saw a bird on the other side of the tank so he went you know raised his rifle to take a shot at it I saw something about five feet to my left and I took one step toward it and that's when my cousin shot at the bird I heard the bullet ricochet off a rock and then go it literally passed inches behind my head like the shock wave of the bullet actually blew my hair up a little bit if I hadn't moved exactly when I did that bullet would have hit me in the head now granted it was a 22 that's very small caliber and it had already lost a lot of kinetic energy when it ricocheted off but that would have been a very bad day maybe a bad month the point is that's one of many dozens of days in my life that I can look back on and ask myself if I had done something even just the tiniest bit different how much would that have changed my life according to one interpretation of quantum physics there is a world out there a real world where I don't exist because I died that day and there's a world where I picked a different College there's a world where I didn't get on the plane where I crossed a different Street and that is true for every decision I've ever made in my life and every decision of every single human being on this planet this is the many worlds interpretation get a brain bucket ready consider the air we think of it as empty space we experience it as empty space but it's actually filled to the brim with atoms and molecules and trillions upon trillions of subatomic particles every time I wave my hand in front of the camera I'm interacting with trillions upon trillions of subatomic particles electrons and protons being forced out of position photons a little particles of light bouncing off of my hand into the camera just this little small space I can create as much chaos as Rian Johnson and a Star Wars convention I say chaos but of course the motion in my hand is controlling the path that these subatomic particles are taking but what if they took a different path according to quantum mechanics not only can particles take multiple paths they act as if they do and this shows up as interference like in the famous double slit experiment which I've covered before quick refresher though in the double slit experiment experimenters fire protons at a photographic plate through a barrier with two gaps the photons show up on the plate as an interference pattern which confirms that they travel as waves because they collide with each other once they get past the slits where the experiment really gets weird is when you only fire one photon through at a time because even though no two photons go through at the same time you still get an interference pattern which means the photon is colliding with something what exactly is going on here this has puzzled some of the greatest minds in physics for the last hundred years and several interpretations have come out because of it the most popular interpretation of quantum physics was developed by Niels Bohr in Berner Heisenberg in Copenhagen around the year 1925 this is why it's known as the Copenhagen interpretation Louie Dubrow came up with the pilot-wave interpretation of quantum mechanics about the same time I've also covered that in a video here both of these interpretations share the belief that the measured path of the particle is the only real path and all the other paths are only potentialities but about 30 years later a slightly drunk student at Princeton disagreed with this while sipping on sherry or so the story goes Hugh Everett the third started to ask the question what if all these other paths really are real and really do exist in other realities realities that then interfere with the paths in our reality it's the interference pattern this of course would mean that there are infinite numbers of realities for each path of every single particle and exist all the time why whatever do you mean that sounds crazy this sounds like it's time for a whoo-whoo alarm but wait perhaps reality as we know it only seems special to us because it's the one that we live in the many-worlds interpretation suggests that there are infinite possibilities out there and other realities that are just as real to other people in those realities there's a reality where a mouse sneezed and where they didn't sneeze in this reality and there's a reality where you did or did not get married Everett's ideas we're not well received let's just say Niels Bohr was still around at the time and he had a way of kind of shutting down anybody that challenged the Copenhagen interpretation after all this was just a paper by a PhD student and I'm Niels Bohr but you're messing with the borehole ain't never caught him something more whole but every did get a lot of pushback from his paper even his thesis advisor urged him to change it because he knew that it would not be received very well thanks to Niels Bohr out there being a bore hole so Evert took a hint and got out of the field with quantum mechanics and actually took a job advising the Pentagon on sort of doomsday scenarios and that was where the idea stayed relegated to the dustbin of history for the next two decades before Bryce DeWitt rediscovered it and thought it sounded kind of interesting Bryce DeWitt was the acting editor of the reviews of modern physics in 1973 and he ran across this paper and was just kind of blown away that nothing ever came of it he called it a new and refreshing take on reality do it publish the full paper in book form in 1973 with Everett's permission and this time with Niels Bohr along gone it was received much better and since the 1970s that many-worlds interpretation has gone from sort of a fringe science idea to something that many physicists are actually kind of starting to get behind Stephen Hawking was a fan Richard Feynman was a fan although to hear physicists tell that Richard Feynman was a fan of literally everything one of the most prominent proponents of many worlds interpretation right now is David Deutsch who is a quantum computer pioneer but his cool factor went through the roof when his name was mentioned in avengers endgame the many-worlds interpretation has sort of evolved over the years as all theories do do it actually he's the one who coined the term mini worlds and other people who have refined on the as well there are a lot of things worth knowing about many worlds but for the sake of simplicity I have narrowed it down to five number one many worlds respects Schrodinger the big debates about quantum theory back in the day fell into two camps really there were the realists which were supported by Einstein and the instrumentalists which Bohr was the leader of Einstein and Bohr famously clashed over this at the Solveig Conference in 1927 it was basically Wrestlemania for nerds and both of these stances are basically different ways of looking at Schrodinger's equation which predicts that particles can take many paths an instrumentalist would argue that it's helpful for us to predict all the different possible paths while a realist would say that there's only one path and we're just missing something so the many-worlds interpretation kind of falls in line more with the realist camp because what it says that we're missing is all these other paths in these other actual realities so it doesn't conflict with Schrodinger's equation number two many worlds depends on a universal wavefunction what the Schrodinger equation describes is the change over time in a wavefunction speaking generally the wavefunction describes the state of a quantum particle or a set of quantum particles and this can mean momentum spin and position in many worlds there's a theoretical wave function that describes the state of the entire universe at a specific time this makes it kind of a deterministic idea so there's no fundamental randomness or any hidden variables that pulls an actual state from a possible state all possible states and all possible paths are real three in many worlds wave functions don't collapse wavefunction collapse is a feature of the Copenhagen interpretation where particles in superposition determined by a wavefunction until that position is measured and then the wavefunction collapses that doesn't happen in the many worlds interpretation now granted we see a wavefunction collapse but that's only because we inhabit the same reality as the path that was taken in that reality so this collapse is only relative to our point of view believers in the Mandela effect kind of rely on this interpretation to explain why things that they remember to be true or not true now they think that maybe they have crossed from one reality to another number four worlds are created by measurement this is the pop science idea that spawned a million movie scripts in many worlds the entire universe is in a superposition of States and when we measure something we kind of diverge into that reality essentially we've created a new world for ourselves in that measured state to live in so for every value that measurement could have shown a universe exists where that value was shown but it's important to note that no matter what universe you live in it is still governed by that universal wavefunction now I've been careful to use the word world in universe when I'm talking about diverging realities many movies that use this as a plot device are not quite so careful I mean after all from my perspective the world that I live in is Universal in scope and consistent you know I can I can look back through time and trace back the entire history of the world through cause and effect so it stands to reason that somebody in a different reality could do the same thing in that they have a universe all to themselves here's the thing though and you might want to be sitting down for this five there is only one universe the concepts were on the Schrodinger equation implied that the universe is in a superposition of States and if the universe is in a superposition of States then so are we my state including the state of my memories is in a superposition so are your memories so are your mom's memories so are your dogs memories maybe that's why my dog always forgets what come inside means there's no reason for another universe because everything that can happen does happen simultaneously in this one universe so while it might be tempting to think of these other worlds as other universes and the strict everett D Witten sense the word worlds might be plural but universe is singular the universal wavefunction changes over time according to the Schrodinger equation but the fact that the universe is in a superposition does not change and we remain in superposition as well from the universal perspective we exist in all possible States 100% of the time so if your brain feels kind of scrambled from trying to understand the many worlds interpretation that's because it kind of is really the biggest question that comes out of all this is what does all of that mean many worlds is a fully deterministic interpretation which means that our choices are only as real as the choices we didn't make does that mean there's no free will does that mean there's another universe out there where I didn't take that one step over and a bullet ripped through my head or maybe didn't rip through my head but caused me to miss half a semester of school or or maybe just bounced right off of me and I'm bulletproof maybe I'm immortal in that world that sounds badass I want to go to there truth is you could run down a million rabbit holes of different things that you could have done in your past and how that could have changed your present but the fact of the matter is if you are still breathing you still have choices and you can still affect your future and for that one thing that's always good for you to work on is to get better at productivity and develop better habits and that's something that you can learn at Skillshare Skillshare of course is an online learning platform where you can learn just about anything that you're interested in from teachers around the world who've done 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please do subscribe I come back with videos every Monday and science a and futuristic topics like this and other things as always t-shirts are available at the store answers with Jo comm slash shirts they're cool they're fun they're nerdy people will look at and go hey and you want people to do that alright thanks again for watching you guys go out now have an eye-opening week and I'll see you next Monday love you guys take care

Channel: Joe Scott

Views: 332,142

Keywords: answers with joe, many worlds interpretation, pilot wave theory, copenhagen interpretation, quantum physics, double slit experiment, einstein, neils bohr, werner Heisenberg, solvay conference, bryce dewitt, parallel universes, mandela effect, david deutsch, schrodingers equation

Id: xies3jrFGpA

Length: 13min 23sec (803 seconds)

Published: Mon Jun 10 2019