Questions about personal identity and materialism with QM and spacetime

Question

Let's assume for a moment that the materialistic view of the universe is correct. There exists a universe that contains energy in various states spread out in the dimensions of space and time that is responsible for our existence. And let's adopt the view of time where the particle states of our brains creating the moments of experience do not disappear into nothingness once they are experienced, but continue to exist eternally as tiny slivers of the universe. Our brains are made up some form of energy in particular states at various times in space. The present moment has always existed as part of the universe, we just were not aware of it in other moments. Our brains are made of neurons connected together interacting with various other chemicals inside our skulls, creating the little reality that we experience with other people, objects, feelings, beliefs, thoughts, etc.

Now in this view, the reason I am experiencing what I am experiencing is that the matter-energy making up my brain is arranged in some particular order. When constructing memories of the past, the brain activates a network of neurons that are arranged in particular way that somewhat resemble previous states, or are perhaps connected in some way to other moments in the past.

So we can think about your whole life as a fixed object in spacetime made up of the whole collection of brain states of your life spread out in spacetime. The apparent movement and change is only an illusion. If the universe is destroyed, it would destroy all the objects and energy in it, past, present, and future. Yet we are here now, so we know that the universe is never destroyed. In this view, it would not make sense to say that you ever die, you just don't exist everywhere in the universe. You are contained in your little time-space, forever. It has no beginning or end. The whole thing just exists at once, but the moments of consciousness are spread out. Each moment contains a short-term memory buffer of the recent past, creating the illusion that you have somehow just moved your consciousness from another moment, when in fact the You in this moment has always been in that moment like the single frame of a movie. This is a static view of the spacetime. In this view, we would be eternally stuck with whatever way the universe just happened to exist.

One problem with this is that it seems from quantum mechanics that the universe does not exist in only one state, but many states at once. We only see a small sliver of the present state at any time, but there could be more to it that we aren't seeing. If the world I am experiencing is just one particular state of atomic particles in my brain, there could be many other life stories that are a part of the universe and the one I am living in this moment is only one of many possible storylines. This comes from one interpretation of quantum mechanics that I read in David Albert's book Quantum Mechanics and Experience, which he referred to as the many-minds interpretation of quantum mechanics. Please correct me if I do not seem to be understanding something correctly.

Now let's say that each particular state of matter-energy in my brain has a certain identity. Any arrangement of matter in the exact same way would create an identical existence/experience. There could be clumps of matter elsewhere in the universe somewhere else in time or at the present moment just like mine arranged the same way, experiencing exactly what I am experiencing. It could be far in the future in another galaxy. It would see the same thing I am seeing, with hands stretched out in front of it taping on a keyboard looking at letters appear on a monitor and believe the universe has existed for the same amount of time as about 13.799 billion earth trips around the sun. It would see the same weather outside and the same stars I see. If this clump of matter happened to be like my brain it would be observing everything that I am observing.

But does the brain need to be exactly the same to be me? My brain has existed in many states in this body in various stages of development, with my current memories and with others. I can experience a brain injury any day and lose much of my brain, memories, and ability to function, but still, experience the universe in some way, even with a completely different personality. So the brain does not need to be identical to mine to be me. It could morph into something like your brain and still be me. I experience one moment at a time perhaps in each of the brains, unaware of the other mes out there. Constructing a coherent sense of what we mean by personal identity can become difficult in this view. Perhaps I would have to identify with just this particular instance of matter in this particular state.

Perhaps as a side question here, does justice become irrelevant if materialism is true?

Could it be that there is only one brain state of the many that experiences the consciousness that is somehow the optimal state?

If that is right, then perhaps we all get our own little optimal universe, and perhaps the other people we observe with various brain states are not actually the real conscious states of their brains or perhaps we all exist as part of some superbrain to keep us on the same page observing the same things. Or the other people may actually exist in some other state, perhaps not associated with the story you are living in your conscious brain state. Or perhaps the past present and future are all in some sort of dynamic state at once. I'm having trouble with this, keeping it all together. It just seems odd that we have this universe exists as it does in these matter-energy states and whatever story we are living has nothing to do with it. If all we are is a jumble of chemicals making our experiences, how could we ever be confident that anything we believe is true? The particles in our brains could arrange in any such way to make us believe anything. It seems unlikely that they would arrange in such a way to hit on the truth.

Does this quickly become incoherent or spell trouble for materialism?

Help me out.

Answer 1

Several questions going on here, but let me try to separate them and answer them each in their turn.

Determinism / Materialism and Fate
In its mathematical construction, it can easily be argued that a deterministic universe (one in which Materialism is the guiding construction) means that our past, present and future are all mapped out according to the rules you've mentioned in your OP. That would indeed mean that free will, choice and the other aspects of our psyche that we experience which indicate that we are masters of our own destiny are in fact illusion and that the choices we make are set (and always have/will been/be).

Is justice irrelevant in such a case? Perhaps. BUT, I'd argue 2 things for keeping it going.

1) Our experience does not intuitively align with Materialism. I feel like I do make choices and I'm prepared to take the consequences of those choices. I believe that I have free will so I act in accordance with that. If I don't, then the knowledge of that may affect how I react but that would only be because that knowledge acts as an additional variable in the life set for me. In any respect, because I don't KNOW whether materialism is right or not, I'm going to act in accordance with my own empirical observations of myself, and that means I believe I have the ability to make (and responsibility for) my own decisions.

2) Justice has historically led to my choices. I cannot experience the universe as a single static 'blob' of spacetime the way we perceive it mathematically as per your OP. But, I can learn from the history of the past and know that the rest of my life is better if I don't make certain poor choices. If we all decide that fate is real and that therefore we're not responsible for our actions, then justice still has a role to play as a limiting factor for our choices. Put another way; if I have free will then I choose to do the right thing because its ethical and because I feel better as a result. If I don't, then even if I don't have any responsibility for my choices I still know that making the right choice is likely to have the best outcome for me, so I still choose it. One could argue that in a deterministic universe, justice is MORE necessary because ethics is removed as a motivator.

Multiple Mes
Yes, it's entirely possible that my brain configuration can exist in different times and places in the universe. In point of fact, this is the very argument behind the concept of a Boltzmann Brain, which exists as a point in time simulation of... well, you. Statistically speaking, it's more likely that you're a Boltzmann brain than you are a real human because a single brain with key information encoded in it is a simpler structure than an entire universe which has evolved to create you, but I digress.

Does this call into account the concept of soul, personal identity, etc.? Most definitely, but I see this more as an opportunity to understand that there's a lot about our existence that we don't (and possibly cannot) know. This question however ties into Formalism, which in AI circles at least expresses the concept that consciousness is merely a by-product of a sufficiently complex algorithm.

If that is the case, then the Boltzmann brain would be identical to you in every respect and would be the same identity as the one you have now.

The Muddle of Materialism
All this doesn't really spell trouble for Materialism per se; what DOES spell trouble for it is our own perception of our life experience. Materialism gives us the idea that fate (however it's expressed through the ages) is correct and our lives are pre-determined and our choices are not our own. That just isn't our experience.

It IS however the experience of scientists (mathematicians, physicists, cosmologists, etc.) studying the universe.

So; either the universe is determinstic, which means that physicists CAN predict the future and extrapolate back through a past we were never present for BUT free will is an illusion, OR

The universe is NOT deterministic, which means that most physical laws MAY not be accurate (because non-determinism means that laws don't always have to be obeyed) BUT it's possible that humans may indeed have free will and be able to impact their future (meaning that they would also be responsible for their actions).

Closing Summary
This is a large and complicated subject, but your OP is one of the better laymen's descriptions of the topic that I've seen and it does spell out the conundrum at the heart of the matter. If space-time is a static object then we have to call our own sense of free will into account, but if humans do have free will, then the ability of the universe to accommodate that ability means that our current understanding of physical laws and the universe has to (by definition) be incomplete.

What do I personally believe? As an empiricist, I observe the fact that some of what I do I do on auto-pilot; my instincts and emotions drive me down set paths. BUT, I also experience myself making choices which I'm prepared to accept any consequences for as well. As a mathematician and scientist, I've seen that certain physical laws are so consistently applied that they HAVE to be accepted without question unless some exception to them is discovered.

Put all that together, I personally believe that the universe is mostly deterministic, but that there is the capacity within it to allow for changes to the program as such. I believe that we have inside us that capacity. Why? That's the bit I can't explain but I do believe that space-time is NOT static, even though it mostly follows a program.