What does the multiverse theory implicate for the free will vs determinism debate?

I understood that you were a physicist (or at least educated in the field), so I'm a little confused about what you're saying re knowing all the states of all particles. According to uncertainty principles, it is not possible to know the exact state of any one particle, let alone every single particle, no?

Similarly, I was under the impression that Bell's theorem had effectively ruled out the idea of hidden variables unless we reject locality? I thought it was generally understood in the field that the universe was either stochastic or not restricted by the principle of locality?

Free will exists.

Quantum theory etc; basically stuff happens randomly.

Been thinking about this, does the multiverse theory support the notion that free will exists?

I've never quite got to grips with this 'multiverse' theory - does it posit that there are an infinite or near-infinite number of universes existing in parallel each one being probabilistically different? If so, does that mean there is at least one universe in which I have the head of a fish?

The uncertainty principle states that we cannot know both the exact location and the exact speed of a particle at the same time. The more we know about one the less we know about the other. Just because we cannot measure the state with 100% precision this does not mean that the state of the particle is uncertain.

That is why I said philosophically free will does not exist because if we did know the state of all the particles with 100% accuracy then we could predict the outcome of an otherwise random event.

So for all intense and purposes because of this uncertainty with measurement we cannot ever know the exact speed and location of a particle thus we cannot ever predict with accuracy what will happen next giving the illusion of free will.

Sorry to be so blunt, but what exactly is your academic background? I remember in a different thread you were talking about working on quantum loop gravity (or something similar) so I assume you are a physicist or a mathematician. Yet in my introduction to QM last winter my lecturer made sure to emphasise that the UP wasn't just a limit on what we can measure or know but an "actual" limit on those properties. He also covered Bell's theorem and a "recent" experiment involving polarised light over a distance of 18km, and the implication was that either there were no hidden variables and the universe is either part of a greater multiverse or actually probabilistic.

Incidentally this wouldn't save free will since a decision caused by stochastic processes is no more free that one caused by deterministic ones.


I'm also intrigued about your above post regarding the multiverse and infinities.. I'm not sure if you've just dumbed it down for we TSR users, but I don't see how an infinite number of possibilities entails that every hypothetical possibility is true somewhere. For example, the constant pi is infinite (non-terminating) and non-repeating, yet AFAIK this doesn't mean it contains all possible patterns of numbers at some point.

Can you explain how the random nature of objects at the quantum level results in my having free will?

A great question! Please allow me to answer although I have a feeling 6th formers won't agree with me

The multiverse theory suggests that there are an infinite number of universes where the laws of physics could be different or the same. If there are an infinite number of universes, there will exist a universe where me and you are having this exact same conversation, but I'm wearing a pink unicorn outfit and you were born with 7 fingers.

There exists a universe where Newton failed Math, Einstein became a drug addict and you're serving life in prison for assassinating the president of the united states.

To make things less complicated... Assume all infinite universes have the same laws of physics, then anything that can ever be true, has, is or will eventually happen including the infinite repeating set itself.

Imagine holding a camera that was able to take a photo of every single particle in the universe. There will be an infinite amount of universe that have that exact same arrangement of atoms.

To relate it to something a little more meaningful. If you had an infinite number of inbiased monkeys all spamming on a keyboard, there will be an infinite number of universes where the monkeys type out the full works of shakespear complete with punctuation and immediately after finishing shakespear the monkeys would start typing out each Happy Potter book in order as they were written without making a single spelling or punctuation error.

tl;dr With infinite universes comes infinite possibilities. If it can happen it 100% will happen and it will happen an infinite number of times.

You're completely missing the point of what your lecture told you. The "actual" limit you speak of is not bound to the particle. If we measure a particles location with 100% accuracy then the speed is simply unknown. We have 0% accuracy on its speed.

Predictability and determinism are not mutually exclusive. Chaotic systems are a class of deterministic systems that are inherently unpredictable. If you actually read what I'm saying I'm agreeing with you that there is a limit but the limit IS NOT defined by the particle, the limit is defined by our measurement. In fact accuracy goes out the window when you measure elementary particles and you have to use just statistics and averages. The very act of measuring the particle affects its properties.

I know what you're trying to say but you seem to think that the particle carries along with it only a portion of the information relating to that particle. For example no matter how accurately we measure, we can only be 30% certain of where a particle is in space. This simply is not true... It's the act of measuring that particle that reduces the accuracy in either speed or location.

Your professor is right in what he is saying but I think you interpreted it incorrectly. Let me just reiterate that it's the effect of measuring / observing the particle that directly effects its properties. See double split experiment.

In regards to your last paragraph remember that I said "If it can be true." This does not mean that PI will contain repeating number sequences because as you've rightly said PI is a non-terminating non-repeating number.

So it would be wrong to suggest that at some point PI will repeat and this is clear because I mentioned if it can be true. If all laws are the same in all universes, there can never be a universe where I circle will have a repeating value of PI. For universes which have the same laws of physics and I assume the same laws of mathematics as us then anything that can be true in our universe, will be true in all other universe and moreover any and all things that could ever be true will be true at some point.

Again it was totally possible in our universe for Einstein to have committed murder and newton to have failed maths. That could have happened, so that means in an infinite number of universe, it did, is or will happen.

Sorry for the long reply and sorry if I wasn't clear in my previous posts I have a habit of getting information across poorly. Also sorry for the long post

2. An infinite number of universes implies that there will be a sub-set of infinite universes that are exactly the same. Unless your use of 'infinite' really means a very large but ultimately finite number.

3 An infinite variation of events in these universes (whether the laws of physics are always the same or always different) invokes an 'absurd consequences' objection. i.e. there will be universes where I have the head of a fish and scientists can't explain it, where my girlfriend gives birth to a TV and scientists can't explain it, and so on.

This is false. There is an infinite number of integers and yet each is distinct. Hence there can in principle be an infinite number of distinct universes (or, rather, you have not demonstrated that there cannot be).

Except all possible universes was specified. If it is not possible under any physical laws for your girlfriend to give birth to a TV, there will not be a universe where she does. There can still be an infinite number of them.

But if each 'universe' is finite, i.e. has only a finite number of possible variations, then it stands to reason that should universes be infinitely occurring then each variation will end up manifesting an infinite number of times. Imagine that the potential variation in a universe is either one egg in a frying pan or two eggs in a frying pan. Generate an infinite number of 'frying pan universes' and you'll have an infinite number of one egg frying pans and an infinite number of two egg frying pans - at least that's how I see it.

On your second point, let's assume you're right and the laws of physics don't allow my girlfriend to give birth to a TV, what about nose length? Under the multiverse rubric surely there will be an infinite number of universes in which everything is the same save for the length of your nose - at what point does you nose length become impossible? I mean, there's nothing in the laws of physics which would prevent you having a nose half a mile long, is there?

I have three immediate problems with this kind of thing:

1. An infinite number of universes requires an infinite amount of energy.
2. An infinite number of universes implies that there will be a sub-set of infinite universes that are exactly the same. Unless your use of 'infinite' really means a very large but ultimately finite number.
3 An infinite variation of events in these universes (whether the laws of physics are always the same or always different) invokes an 'absurd consequences' objection. i.e. there will be universes where I have the head of a fish and scientists can't explain it, where my girlfriend gives birth to a TV and scientists can't explain it, and so on.

But if each 'universe' is finite, i.e. has only a finite number of possible variations, then it stands to reason that should universes be infinitely occurring then each variation will end up manifesting an infinite number of times. Imagine that the potential variation in a universe is either one egg in a frying pan or two eggs in a frying pan. Generate an infinite number of 'frying pan universes' and you'll have an infinite number of one egg frying pans and an infinite number of two egg frying pans - at least that's how I see it.

On your second point, let's assume you're right and the laws of physics don't allow my girlfriend to give birth to a TV, what about nose length? Under the multiverse rubric surely there will be an infinite number of universes in which everything is the same save for the length of your nose - at what point does you nose length become impossible? I mean, there's nothing in the laws of physics which would prevent you having a nose half a mile long, is there?

If each universe only has finitely many possibilities then there are only finitely many universes by the definition of the multiverse. But there can be infinitely many possibilities (ie infinitely many universes) without every possibility being satisfied in some universe.

I'll leave your objection to my second point alone for now since I'm waiting on keepyourchinup to explain something to me. I was under the impression that the only possible universes were those that could be achieved had wave functions collapsed differently to how they did in this universe. As far as I know, this does not necessitate the existence of universes where everything hypothetically possible is true. Hence there could only be a universe where I have an arbitrarily long nose if this could be achieved through possible different wave function collapse.... but like I say, I'll step back for now

You are completely right but take a step back for a second and picture this in terms of infinitely many universes. Assume for simplicity that we have an infinite amount of big bangs all ready to go off. From this moment forward, anything that can happen will happen. I really don't know how to put it any simpler. Forget wave functions and probability... when you have infinite universes probability goes to 1. If you could map every single event our universe has undergone sinse creation and compared it's state at every given moment in time, you would find another universe, and infinitely many of them which have the exact same state. Compare the states 1million years later and again you will find infinitely many universes which hold the same state.

You start to ask yourself sooner or later as more and more events occur we'll eventually become unique? The answer is no. We might take the current state of our universe and peer out the window as it were for another universe that looked like ours, not just visually but particle for particle. We might look through (grahams number) $g^{g^{g}}$ universes and find they're all different, but we still have infinitely many universes to look through. Don't you see it's impossible NOT to have infinitely many universes which are exactly the same as ours... not only that but if it can happen, it will happen and there will be an infinite amount of those.

This isn't a dig personally to you Implication but I think people, myself included don't really understand infinity, we like to think we do but when it really boils down to it, our brains just can't handle it.

I don't even believe in the multiverse theory. I believe our universe has always existed in one form or another but this carries along infinity so for the moment I just have to accept infinity even if it leaves me kicking and screaming.

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3.I'm not a biologist ok but I'm pretty certain it is physically impossible for your girlfriend to give birth to a television... Would you say it's physically impossible for a person to have an arm that is 3miles long? Again I'm not a biologist but I strongly believe it is impossible. If it's impossible in this universe, it's impossible in all universes...

Free will exists.Quantum theory etc; basically stuff happens randomly.