Does science support the multiverse and a persistent past and future? Think again.
In an Multiverse-Eternalist world, what is a One-Universe-Presentist to do?
In an Multiverse-Eternalist world, what is a One-Universe-Presentist to do?
Ask yourself if you agree with these statements:
My life is predetermined.
The past and future exist all the “time”.
There are many copies of me out there somewhere.
Anything that could happen, does happen somewhere.
If you agree with all of these, you might be a Multiverse-Eternalist.
Eternalism is the belief that the past and future exist “out there” somewhere. I have written about this in two articles now here and here. The idea is that, while you are only conscious of one moment at a time, all the past yous and future yous exist already. Yet, somehow, your consciousness has left the past you and has yet to enter the future you.
The multiverse is the idea that at every moment the universe is splitting into multiple copies of itself and many copies of you exist in other universes. Each copy is a distinct conscious being. They all share your past but not your future.
If you believe in both these like many physicists, you believe in what I call the multi-me point of view.
If you disagree with both ideas, you are a One-Universe-Presentist. I call this the one-up point of view, and it is rare among scientists.
Some do still hold out though.
One counter to multi-me modernist meta-physics is post-modernism, a subjectivist philosophy that can easily degenerate into solipsism. While modernism wants a completely objective picture of the universe where the self isn’t part of it, post-modernism argues that there is no such thing as objective knowledge. Rather each person can only see things through the lenses of their own perceptions and biases.
A post-modernist can cling to the one-up ethos because other times and places are not part of my subjective experience. Now is the only time. Here is the only place. I am the only one.
This can be a slippery slope. Consider this statement:
I can obtain objective knowledge about reality beyond myself.
If you said no to this, you might be a solipsist.
As a solipsist you live happily in one universe in one moment in time. This universe has population one: you. All knowledge, you believe, is subjective and ultimately is just self knowledge. You live your truth because that’s the only truth that exists. You are just an ape looking in a mirror.
Needless to say, post-modernism and solipsism in particular give many scientists the willies. To get away from it and back to objective knowledge, many of them insist that the cosmos must contain many different realities at once: the past, the future, and all the outcomes of random chance like whether you forgot your keys or not today. Nothing can be left out.
It’s the multi-me way or solipsism, they say.
It turns out that science has a lot less to say about metaphysical questions than many science writers would have you believe. To prove my point, I am going to show that the one-up perspective can be made objective with two ingredients:
1. Aspects of reality are hidden from us.
2. The entire universe is in constant contact with itself.
All of this can be made to agree with modern physics as well, provided we reject the prevailing philosophical paradigm.
How did Eternalism and the Multiverse become part of the dominant zeitgeist? Two reasons: General Relativity, Einstein’s theory of gravity, space, and time and quantum theory, the theory of the bizarre world of the very small. Together these theories comprise the realm of “modern physics” which are any physical theories developed past about the 19th century.
These, combined with certain philosophical (I would say religious) notions of determinism and positivism (the tendency to focus only on what is observed and not what may be hidden), form the multi-me point of view.
Einstein himself was an Eternalist (though not a positivist) and imprinted his philosophy on his theory of gravity. Through General Relativity, the idea of time as a separate, universally shared experience was done away with and time and space were shown to be inseparable. The new four-dimensional physics of relativity forced us to accept that each of us has a different experience of the present moment and the only thing we share is this four dimensional universe with time stretching back to the Big Bang and forward to the heat death of the universe.
Even the notion of events being simultaneous was challenged, as Einstein and others showed that two events could appear simultaneous to one person or “observer” but not simultaneous to another who is in a different state of motion.
If simultaneity didn’t exist, then how could the present moment be anything but an illusion? To maintain an objective reality, Eternalism was seen as the only option to avoid solipsism.
Einstein was pretty happy with himself until quantum theory started to challenge his own viewpoint of a single objective but four dimensional universe. Experiments such as the double slit and thought experiments such as Schroedinger’s famous cat told us that multiple realities could exist in “superposition”. The cat is both alive and dead until you look at it.
Clinging to the idea of a single objective universe, physicists for decades believed in the idea of wavefunction collapse (the so-called “Copenhagen” interpretation), that the act of observing the dead or alive cat in the box caused a fundamental shift in the universe towards one reality or another.
Recently physicists have turned away from this orthodoxy to embrace the multiverse. The multiverse proposes that all realities exist. The cat is alive in one universe and dead in the other, and it is we who are only seeing half of the outcome, not the universe.
When the box is opened, the universe splits in two and one universe has a dead cat and a scientist observing a dead cat and the other universe has a live cat and a copy of that scientist observing the live cat. Each copy has a different experience and thinks theirs is the only one.
Eternalism and the multiverse satisfy certain philosophical and even religious urges that I think explain why they have become so popular. Eternalism removes non-deterministic free will because it suggests that all our actions and the outcomes of those actions are predetermined. That includes moral action. Some of us are good people, determinism would say, while others are not good. They have no choice over whether they are or not. Even if we can make our own choices, we cannot affect the desires and motivations that lead to them and so the future is certain. Thus, Eternalism helps to absolve anyone of responsibility for anything.
You can subscribe to free will interpretations of Eternalism (such as the half-block theory which is also semi-Presentist that only the past exists but the future does not) and deterministic interpretations of Presentism, so it is by no means the only urge that it satisfies. It also satisfies the desire that many of us have for the past to exist somewhere “back there” behind us. Our lost loved ones, for example, are forever encased in the amber of the four dimensional universe. They are there just not visible because our consciousness has moved on. Perhaps one day we will even travel in time and be able to visit that past, as some have suggested is possible in Einstein’s relativity.
Like Eternalism, the multiverse satisfies a desire for determinism. For decades, since the discovery of quantum theory, a single objective universe required it to be random and for that randomness to have a mysterious mechanism to decide which outcome of a random process to choose. God had to play dice. Every time we measured the state of some subatomic particle, God had to roll. The multiverse does away with that. Instead, every outcome on the die happens, just in different universes.
Besides satisfying the determinism urge, the multiverse explains coincidences in a more satisfying way. Many scientists don’t like it that the universe seems so well suited to human beings. It implies something mysterious, almost divine, about its creation. If, however, all possible universes exist somewhere, then there is no mystery. This is simply the universe that worked.
Some philosophers have fought back against the multi-me with solipsistic arguments. If you accept that you have one place in space and time and can only access your own self, they reason, then you can get rid of past, future, and other universes. Rather, everything I observe is simply a result of my own internal model of the universe and how I interpret what I experience.
There is some sense to this. After all, the universe doesn’t know what a cat is, so why would it make one for a live cat and one for a dead cat?
But is solipsism the best we can do for the one-up philosophy? I argue no.
There is a third option, one that can support both Presentism and a single universe without falling into solipsism. It is the “hidden information” approach that I talked about in my article on Bohmian theory.
Rather than accept Einstein’s point of view that the universe is a four dimensional block where everyone has a different idea of the present, we can say that the universe as a whole is “foliated”. This means that it has a definite present moment throughout the entire universe. The four dimensional block is imaginary. The universe is only three dimensions. As the universe evolves in time, its three dimensional structure actually changes.
The key point here is that, for all this to work with Einstein’s relativity, the present moment cannot be determined by measurement. It is a hidden piece of information. Therefore, while two observers can’t agree on what simultaneous means, there is a hidden notion of simultaneity in quantum wavefunctions for particles and forces.
The reason this works is because of the other aspect of Bohm’s theory, that all particles and forces have an exact hidden state and influence one another instantaneously. This instantaneous connection between everything implies a single present moment, but not one we can use to send or receive information in violation of relativity.
Likewise, because every particle in the universe has an exact hidden state, there are no other universes containing different outcomes. Rather, the outcomes already exist and are only observed when they are measured. The cat is already dead or alive before you open the box. The universe evolves in time and all the hidden states evolve with it, influencing one another throughout the universe all at once.
While this may seem strange, it is backed up by mathematics that show that it is equivalent to standard quantum theory. The difference is that it allows a single present moment and an exact, hidden, instantaneously communicating state of the universe. It is a one-up perspective but also objective. We can all share this reality. It is only hidden.
Why does the universe appear to be four dimensional?
We already know and have measured in countless experiments that quantum phenomena violate Einstein’s relativity. Yet, for us non-quantum beings, the universe obeys Einstein perfectly. There is a reason for that.
The four dimensional character of the universe comes from how quantities that have a direction like velocity and momentum transform in a four dimensional way. But that doesn’t imply that the fourth dimension exists “out there”.
Let’s explore this idea in a thought experiment:
Suppose you and a friend are in a room. Everything is completely dark except exactly where you are. You are in a motorized chair with a single fixed speed that is not under your control. You can only turn. You and your friend can move in different directions from one another, but not at an angle greater than 180 degrees from one another.
By observing the area around your chair, it seems like you are moving around a large room.
(Your friend is a solipsist, however, who thinks that only the point where his chair is exists. Go figure.)
You turn on the lights.
You see now that you and your friend are on a long roller and what you thought was an infinite room is just a long corridor with black non reflective walls. It turns out that when you change direction, your chair just speeds up or slows down to compensate. That way you stay centered on the roller. This is why neither of you could tell you were on the roller.
Bohmian theory works the same way with time and space. The universe is three dimensional (sometimes called a “hypersurface”) but, because of our ignorance of what that hypersurface is, we have to describe velocities, energies, force fields, and particles as if they were four dimensional. These transform in a four dimensional way according to what is call “Lorentz” invariance which is sort of like the motorized chairs speeding up or slowing down when they turn. As long as everything transforms that way, you can’t tell what the present moment is.
Why would I want to believe this?
Part of my reason for making this argument is to counter the erroneous idea that physics points to a particular interpretation: the multi-me. You can believe whichever you want but you can’t argue that physics is backing you up. In this case the consensus is philosophical not scientific.
If you like this article, you might like this one:
Bohmian Mechanics: the past and future may not exist
A 70 year old interpretation of quantum mechanics challenges everything we think we know about the universe.medium.com