The simulation hypothesi.., p.15
The Simulation Hypothesis, page 15
Parallel Lives and Future Selves: The Great Game
If parallel universes are being created each time we make a major decision (or a minor one, in the realm of quantum physics), then there is a directed graph of multiple universes that are branching out, as shown in Figure 23.
This would imply that each branch gets branched again, and we end up with an ever-increasing number of universes each time a quantum decision is made. However, one theory, which was the subject of one of Stephen Hawking’s final papers, is that the actual number of parallel universes may not be infinite but limited to a smaller number.
This idea of a limited number of parallel universes—based on a limited number of different configurations of particles (and/or at a higher level) and a limited number of choices—implies that even though every quantum decision spawns a universe, some of these universes are similar.
Taken at a macro level, this means that certain universes are actually the same. This makes more sense intuitively if, for example, you decide to have eggs for breakfast rather than toast but then have eggs tomorrow. These two universes may be similar enough from your perspective, especially compared to the universe where you ended up marrying someone else, or lived in another country, or were never born!
Figure 23: A directed graph of branching possibilities, or World Map.
One way to express this is that while each choice might take you to a different place, some of these choices will see you end up in a similar state of the universe. The result could be thought of as a grid of “possible futures” as shown in Figure 23. It is actually a directed graph of different possibilities—a “future map” for an entity or particle starting at point A.
Point A is the choice we are making today, with two possible outcomes (of course you can generalize this for any number of choices, but since we are dealing with quantum superposition here, let’s start with two). Each choice then branches out and creates two different universes, and so on. However, some of those choices may come back to the “substantially similar” universe. You can see that it’s possible to get from point A to point C by following two different paths and different sets of choices.
When thought of at a higher level rather than at the level of atomic particles, interesting metaphysical questions are raised about free will versus pre-determination and the range of possibilities that are available to us. If we think of this kind of “world map” of the choices that we might make now or in the future, we get into another philosophical question:
Do all of these parallel universes actually exist? Or are they just “possibilities” based on choices that we can make—whether at a quantum level or at a macro level—in our lives? Similarly, are these future selves really just “probable future” selves sending us back information or are they actually physical versions of ourselves?
Of course, these are exactly the kinds of metaphysical questions that Wheeler and others were hoping to avoid with the many worlds interpretation, but they crop up nevertheless. And they are not easy questions to answer.
Fringe and a Parallel World
Almost as soon as the idea of parallel worlds became popular, it was picked up by science fiction writers and has become extremely popular. In fact, most people probably first think about parallel universes through science fiction.
One of the best-known examples in recent years was the TV show Fringe, which aired from 2008–2013. It became famous for exploring the idea of a parallel world. The show’s protagonist, Olivia Dunham, is an FBI Agent who enlists the help of Walter Bishop, an archetypal mad scientist who begins the series in a mental institution, and Walter’s son, Peter Bishop.
As the series progresses, we learn that Walter, a brilliant scientist, along with his scientific and business partner, Dr. William Bell (played by Leonard Nimoy, in one of his last roles before his death in 2015), has discovered the ability to view an alternate universe that contains alternate versions of ourselves. By developing a screen that functions as a window into the alternate universe, the characters can view what is happening in this alternate world and what their alternate selves are doing. Peter is dying of a rare disease, so Walter rushes against the clock to find a cure. When his son dies, Walter finds a way to go into the alternate universe and cure the “other” Peter. We then find out what makes Peter unique—he is not from our universe, but is the Peter from the “other” universe!
Many TV shows have explored the idea of alternate universes. Fringe did a great job of depicting a world like ours but with some subtle and not-so-subtle differences. The alternate versions of the main characters, though looking exactly the same, had very different personalities resulting from their different experiences.
Game Theory, Simulations, and the Directed Graph
Let’s come back to the idea of the simulation hypothesis. As I was exploring the graph of “possible universes,” I was reminded of the AI that I was building as a video game developer.
Is there a limit to the number of physical universes? If, on the other hand we are not in a physical but rather in a simulated reality, then this question of whether the probable future selves or parallel worlds are real or simulated becomes a little more palatable. A computer can simulate a large number of possibilities very quickly—in fact, this is one of the major ideas behind running simulations. Monte Carlo simulations, for example, run a large number of “random” possibilities in order to understand which are the most likely scenarios that may emerge.
It turns out that video games, particularly AI within video games, are pretty good at branching out possibilities and measuring them, and bringing this information back into the present to decide what to do next. Depending on which choices are made in the game, the simulation may run to the point of actualizing one or more of these, but from the current point in time, they remain future possibilities.
When represented in a directed graph, the “World Map” shown in Figure 23 reminded me of the video game I made for our class project back at MIT. The way that the computer chooses the next move is to project the possible futures and then use a certain algorithm to “rank” those futures using an “evaluation function.” Then it brings those values back to the present, and the AI chooses the path to follow based on the best value of the evaluation function. This is referred to as the “minimax” algorithm, which is shown pictorially in Figure 24.
Did the possible futures the AI was calculating in our game actually exist? Or were they just probabilities?
The nature of the evaluation function that is being used to evaluate the possible futures is relatively simple in a game like chess or checkers. In the quantum realm, or even in the macro realm, is there some AI or part of us that is spinning off different possible futures and then evaluating them in some way using an evaluation function?
How would this evaluation be done? We would need to represent the state of the universe using some kind of information and then compute it using an evaluation function. You can see that while we started with physical universe, the more we delve into the quantum realm, the more we are reminded of information and computation. If we can define our “game state” as the state of all particles in our current physical universe, then the game state can be varied and evaluated by a computer program very easily.
Figure 24: The minimax algorithm: a simple AI for evaluating future outcomes and choosing the best path.34
Or, as Fred Alan Wolf suggests, another way to think about it is that each possible future is sending us back information on the evaluation function if that possible future was “spun up.”
In simulations involving a large number of independent variables or “simulated beings,” the nature of the evaluation function is not so easy to define. What evaluation function could be used to evaluate possible futures in a multiplayer shared online simulation?
This is also not a simple question to answer. The evaluation of the best path would depend on the nature of the “game,” how we keep score, and how those running the game define what is most optimal in a given set of circumstances.
Let’s look at some scientific possibilities in this chapter, but we’ll revisit the idea of evaluating multiple timelines in the chapters on Eastern mystics, karma, and reincarnation, which provide an elegant answer from well beyond the realm of physics.
Campbell’s Fundamental Process and Profitability Function
Physicist and defense weapons contractor Thomas Campbell has been advocating the simulation hypothesis as part of his “big TOE” (Theory of Everything) since the publication of his book, My Big TOE, in 2003. In this book, he describes a possible model for an evaluation function that could be used to evaluate possible futures and choose the best possible future.
Campbell posits that there is a “Fundamental Process” that drives evolution of consciousness, biology, and even inanimate objects. The Fundamental Process, as he defines it, is a process that tries out every possibility, through trial and error, and gravitates toward the possibilities that are evaluated as the “most profitable.” In his book, he writes:
The Big Picture Fundamental Process of evolution (or fundamental process for short) is as follows. An entity starts from any point (level) of existence or being, spreads out its potentiality into (explores) all the available possibilities that are open to its existence, eventually populating only the states that are immediately profitable while letting others go.35
The most profitable states depend on the nature of the entity or object we are talking about.
Campbell asserts that for carbon-based biological entities, the assessment of profit has been based on survival, and thus it aligns closely with the natural process of evolution. For non-biological entities, Campbell asserts that the most profitable is the state which requires the least amount of energy—the easiest and cheapest to achieve. For conscious entities, like humans and other living beings, the most profitable usually means to reduce entropy, move toward greater order.
Moreover, Campbell asserts that the fundamental process is recursive and that it continues as long as there are profitable states to explore. Campbell believes this process happens at all levels, from the subatomic level to the level of our biological cells to the levels of our consciousness and even to the universe outside of what Campbell calls the Physical Matter Reality (PMR), meaning the physical universe we can observe.
Campbell asserts that the universe spins up possible universes and outcomes, evaluates them using his profitability function and then comes back and chooses the universe that is most profitable. This is similar to how video game AIs choose which path to follow—by evaluating possible future states based on some evaluation function.
Parallel Worlds Must Be Computed
There is some debate among physicists and philosophers on whether the parallel universes posited in the MWI are actually real, physical worlds, or if they are just probabilities tracked by some type of computer.
For these copies of the universe to be real, someone or something would need to create a “copy” of the current universe each time a decision is made. In a physical world, this would require copying every single particle in the universe and then allowing that new universe to move forward. In computation we could call this an “expensive” operation!
This sounds like a needlessly complicated process. Which brings us back to the idea of optimization—the heart of computation in the world of video games.
Physical copying is not a process that is easy in the physical world. In biology, cloning at the level of cells or organisms may be a good analogy. However, even in biological processes, clones take time and must be grown—they can’t be done instantaneously!
The complexity that would be involved in the cloning of universe, placing all of the particles in the exact same position, is astronomical. In fact, this process doesn’t fit well into any known physical, biological, or chemical process.
However, branching and copying are common structures—with algorithms in computation particularly in the area of computer graphics. In fact, in early video games, as was mentioned in the last chapter, the world was defined as a series of pixels that were laid out as a series of bitmaps, and showing that part of the screen was a matter of copying those pixels from disk to memory and then rendering the display of those pixels onto the screen.
As computers and video games have evolved, the processors used for these games, GPUs and CPUs, have evolved to provide functions that are optimized for the task at hand. It’s not at all unreasonable to assume that if the universe gets “copied” or “branched” that there are optimizations for accomplishing this—and that what is being copied is actually information and not physical particles. Like a video game or a simulation, this information exists only in digital form in some kind of cyberspace, and particles (or pixels) are rendered only when necessary!
Stephen Hawking suggested that the number of universes may not be infinite after all but limited to the number of particles. This implies that many of the particles in the copied universes are in “similar” configurations.
This is a common optimization technique used in computers in general and computer graphics in particular. In fact, most images are compressed based on the fact that many pixels are actually the same—in a picture of the night sky, for example, most of the pixels are black.
As we think about a computational structure that could support multiple universes, many of the universes will have particles in the exact same location. A computational model of the universes as information allows for significant compression and optimization, and computation provides a mechanism that might actually be able to produce this kind of result: a giant computer system crunching numbers with a rendering engine that only renders when it’s needed (a form of quantum indeterminacy only when it is needed!).
Parallel Universes and the Simulation Hypothesis
The theory that all reality is in fact an artificial or virtual simulation might be the only practical way that the many world interpretation (MWI), the delayed-choice experiment and the idea of future probable scenarios could be true or implemented. If the universe is seen as a virtual world with a game state, then we can envision how multiple probable futures can be generated (as information, not as physical worlds), and then choices can be made through this branching tree of possibilities using some evaluation function.
In particular, the simulation hypothesis provides a better model for how these aspects of our reality could actually work:
Branching. Spinning off multiple probable realities, while extremely difficult for a physical reality, is almost a trivial matter if we are in a simulated reality. The nature of simulations is such that you can branch off multiple simulations using the same computing power and without requiring additional physical resources. This is true whether you subscribe to the “real” or the “unreal” interpretation of many worlds. Obviously if it’s the “real” interpretation, then the physical universes need to be copied. If it’s unreal, then these are probabilities and are really a type of computation that can be done like AI in video games.
Optimization. As we look at the maximum number of universes as something less than infinity, we can start to think about how to optimize creation and storage of all the information in the “universe.” While originally thought of as a physics problem, this is actually a computation problem and one that has been solved to get our video games into the state that we have them today. We optimize based on sameness of pixels in graphics, tilling, reducing duplication of information, and caching what’s needed. Similarly, the only way to have so many different universes may be to optimize based on the sameness of universes—which are near each other and which branch out.
Retrocausation. The idea that the future can influence the past is non-intuitive and provides for the ability of paradoxes. However, if the futures are possible futures rather than actual futures that are sending back information to the present based on an evaluation function, then this becomes a more understandable process.
Once again, we see that what seem like unexplainable findings of quantum physics start to make more sense when we consider them in the context of the simulation hypothesis. In the next chapter, we’ll explore other topics in physics that start to make more sense when we view reality as a pixelated simulation rather than a physical reality all around us.
Chapter 7
Pixels, Quanta, and the Structure of Space-Time
In the previous chapters, we looked at some of the confounding aspects of quantum physics and showed how the simulation hypothesis could provide a more coherent explanation for these mysteries. In this chapter, we’ll bring together various concepts in relativistic and quantum physics to explore the fundamental fabric of the physical world and show how our physical world may not be as “physical” as we thought—that we actually live in a pixelated, quantized reality.
In Newton’s classical model, as we discussed in the introductory chapter on physics, motion was thought to be continuous. For example, the planets move in smooth orbits or lines around the sun according to Newton’s equations of motion. In fact, it was assumed that both space and time were continuous.
In the years since, we have found space and time are more variable than we thought, with the discovery of the atom and the strange behavior of subatomic particles, not to mention Einstein’s theory of relativity.
These characteristics of the real world—the structure of space-time itself—are actually more explainable if we live inside a pixelated reality, just like the virtual worlds that exist inside video games. This idea of “discrete” quanta of space (and theoretically of time), rather than continuous values, are very similar to how video games work.
