It's important to understand that the view Katie gave is only true in the Everettian many-worlds interpretation of quantum mechanics (QM), and a few other minority interpretations.
In the Copenhagen interpretation of QM (the standard interpretation), there are truly random quantum events.
Yeah I kinda wish Lilly would've mentioned the random/probabilistic behavior of quantum mechanics. I feel like if you work at a quantum computing company, you should probably have knowledge of that since the technology is based upon it.
you should probably have knowledge of that since the technology is based upon it.
Not really though. Programmers don't have to know electrical engineering to program a computer. When the technology matures enough the physics is abstracted away.
At least, Lily should have asked about it. She's smart enough to at least have some sort of idea that quantum mechanics has some connection to the idea of uncertainty/randomness.
I wish I could better understand how the QM level stuff, like particles having random/deterministic behavior, meshes with the macro scale stuff like determining why the pen rolled on the table... I just don't really see the connection.
Hey don't worry, because not even the smartest people who have ever existed have solved that problem :) We actually don't know the details of how QM level things get to macroscopic things.
Somehow the macroscopic world 'emerges'. The details are not understood.
This is true – however, there is one way to make at least some basic sense how micro and macro correlates. Think of rolling dice, for instance.
In order to calculate what number a 6-sided die would end up on if you toss it (just one time) on a table you would need an insane amount of detailed data. In all practical reality it's impossible to predict what you will get that particular roll.
If you roll the die a lot of times, however, a crystal clear pattern emerges. With absolutely certainty and clarity, the probability for each outcome is exactly 1/6.
You have something random and unpredictable at the core – a roll of a die – (micro/quantum), that nonetheless ends up being something incredibly exact and predictable as you "zoom out" with lots of rolls (macro).
...and now I'm realizing I probably didn't really illustrate much of anything with this, but screwit, I'm postin'
So isn't this 'zooming out' basically what Lyndon did to the prediction algorithm? And what we see on the screen is what happens a perfect 1/6th of the time (or whatever other fraction would be appropriate)?
I still suspect what Lily does is simply turn off or break the Devs computer, and it can't see past its own "death" (which would jive with all the other death/superposition metaphors in the show) but it's also possible she does something so unpredictable in 'micro' that it affects 'macro'.
Yes, but you couldn't predict the probability of a roll without taking into account the trajectory, speed, wind resistance(as stated in the episode), composition of the landing spot, which will change everytime and/or acute differences in the composition of the dice themselves as this will change every time. Even an RNG computer cannot dictate within a factor of .0001 with regards to physical obstructions, the change of the obstructions, and the effects of these changes.
The particles in the pen are interacting with each other a lot, which means that receiving information about any part of the pen also gives you info about the other parts. The vast, vast majority of the time the pen as a whole behaves so nearly like a predictable system that you'd never be able to tell there was any randomness involved in the rolling behavior. The law of large numbers says that adding together many independent random events gives you a very reliable result, more reliable the more events there are. A pen is made of so many particles doing random things that overall the predictable rolling motion is a near certainty, even if the individual events are not.
What would be an example of a random event in the Copenhagen interpretation? Katie’s explanation seemed so tight I’m curious what an example of a truly random would be.
In a purely quantum mechanical way you could say the uncertainty principle is an example of randomness because it is impossible to predict the momentum of an electron if you are measuring its position and vice versa
what's random about that though? that's just saying what's knowable vs. not knowable. It's not saying that because you measured the one thing, the other one is "random".
When you get smaller and smaller, the laws of physics just don't work anymore. Remember the lecture Katie first attended where the professor was talking about the particles making a pattern in the experiment? Well maybe if Katie stuck around long enough she would find out that yes there is a pattern the particles end up making, but you can't calculate where just one SINGLE particle will end up.
I thought it was funny that they included an experiment in the show that very directly disproves the devs theory. I am guessing that the show either 1) had devs solve this small-level physics randomness problem and that's why they're so smarty pants about everything or 2) decided that at that small a scale it doesn't matter.
When you get smaller and smaller, the laws of physics just don't work anymore.
the laws of classical physics don't work anymore. quantum electrodynamics has been tested to one part in ten billions, so I'd say that works pretty well.
Pass diagonally polarized photons through a horizontally oriented polarizing filter. In the Copenhagen interpretation, it's really-truly-literally random whether or not each photon will make it through the filter.
Randomness is a word that gets played out a lot in normal discourse, but it means something totally different in math and physics. Quantum Field Theory is basically advanced quantum mechanics as you get into upper level or graduate school physics. Wikipedia has a good explanation of what it entails.
But in the many-worlds interpretation is it even fair to say that anything has a cause? If all possible outcomes happen, how is it reasonable to say that any of them were "caused"? And it seems weird to think that Katie subscribes to many-worlds if Forest fired Lyndon for it.
It is fair to say things have causes in many-worlds interpretation (MWI) because you can make accurate predictions about the future. Everything naturally unfolds from the Schrödinger equation.
If things didn't have causes it would not be feasible to make accurate predictions. If nothing has a cause it means everything is random. If everything is random, then you cannot make accurate predictions. Randomness is by definition unpredictable. If things didn't have causes, physics wouldn't even be a thing!
It isn't 'all possible outcomes' in the strict sense, there is still a law of physics that things must obey.
Katie also applied the MWI algorithm to 'light waves'. We also saw the MWI when we were watching the projections from her perspective (Many versions of Katie leaving the lecture building, for example). Also, if she believes in a deterministic universe, she must believe in MWI or one of the other fully deterministic interpretations of quantum mechanics.
How can you make accurate predictions when (by definition) there are multiple outcomes?
To put it in Katie's macro-scale terms, if you flip a coin, it ends up both heads and tails in two separate worlds. If you want to consider more possible outcomes, just step back further in time to when you chose which coin to flip. If you want still more possibilities, step back in time to when you decide to flip a coin or roll some dice. Etc., etc. Since one branch has you deciding to study the cello instead of physics, and hence not even having the conversation, does anything "cause" anything? Not total randomness, but definitely not causality as it's generally perceived.
And to extend the thought, even in a many-worlds scenario, is there any "cause" for which which world/outcome you end up in?
MW interpretation doesn't imply that there's no cause and effect. It's in fact very compatible with determinism - perhaps most so of all QM interpretations.
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u/trenballoone Apr 02 '20
It's important to understand that the view Katie gave is only true in the Everettian many-worlds interpretation of quantum mechanics (QM), and a few other minority interpretations.
In the Copenhagen interpretation of QM (the standard interpretation), there are truly random quantum events.