Do We Live in a Simulation? Implications for Morality and the Beauty of Physics.
There’s been a lot of fuss lately about Nick Bostrom’s ideas that we live in a simulation as a result of an article in the New York Times. Here I’ll provide some analysis of Bostrom’s bold claim, including a proposed mechanism to explain my grandfather’s assertion that mathematical simplicity and beauty were indicators of underlying truth. I’ll also explore the implications of this possibility to our daily lives, and show why this is another reason to follow Transhuman Morality.
Simplified Simulation or Complete, Accurate Model?
The simulations Bostrom describes would not be precise to the subatomic level, but rather use abstractions to simplify the computation. Instead of simulating every electron, proton, neutron, quark, etc in each person’s body and everything around us, it might only simulate synapses and neurons in our brains. Such short-cuts would be extremely useful to accomplish the goals he describes of virtually resurrecting ancestors. (A convenient version of heaven.) Just simulating the brains of the inhabitants of a virtual world is drastically easier than accurately simulating an entire universe down to the subatomic level. For many purposes, including the ones we are likely to engage in anytime soon, it is sufficient.
The software to run a simplified simulation like this would put its designer in an interesting predicament whenever the simulatees decide to build a new particle accelerator or perform some other experiment that pushes the limits of their understanding of fundamental physics. Would a dialog box appear on the simulation screen asking the designer to make decisions about how to treat a new class of quark that had never been observed? Then once the designer answers this question the simulation moves on? Moreover, so many trappings of modern life are the result of applications of scientific breakthroughs like this? For example, we could have never built semiconductors and thus computers without a solid understanding of quantum mechanics since they take advantage of quantum effects. So closing the dialog box would require not only require describing the results of this experiment, but also coding up a bunch of new high-level abstractions that represent things like semi-conductors. The simulation would need to know when it could use the molecular mechanics model, and when it would have to substitute a more detailed model or a coding abstraction that simplifies the results of more base laws.
If we lived in such a simplified simulation, it seems likely that chinks in the armor of reality would periodically appear. Modern science has few inconsistencies like this. (The big bang and quantum randomness being the two biggest two exceptions IMHO.) I would wager that if we live in a simulation it is a completely accurate physical model that started with the big bang and covers the entire universe including our own evolution from primordial soup. It’s not clear to me whether or not our universe has enough matter/energy to build a computer powerful enough to run such a simulation. I should dig up my notes from Yael Maguire’s excellent talk at Foo Camp on the fundamental limits of computation to be sure, but I know it would chew through at least solar systems worth of our universe if not galaxies or more to simulate a comparable universe. It seems more likely to me that if our world is simulated then the “host world” is governed by a different set of physical laws. This point is debatable and important, but I’ll assume from here that the host world is governed by different laws.
Motivations of the Simulation Designers and Implications for Personal Morality
As the NY Times article points out, the simulators might just be bored, doing the equivalent of playing video games with us. Or they might be scientific researchers investigating how changes to fundamental laws affect how worlds evolve. Whatever their goals are in running a simulation of this scale, they are almost certainly interested in the complexity that we are creating here and now. But how should we behave?
Robin Hanson suggests that as individuals living in a simulation we should try to lead the most interesting, impactful lives that we can. This goal attempts to optimize for the case that the simulators will pick individuals from this simulated society to do something special with. I think it extremely unlikely that the designers care about individuals at all. If they’re looking at anything, I’d bet it’s entire societies. So, if we are living in a simulation, I argue that we should do our best to advance technology as an insurance policy against extinction. I have written a fair bit about the transhuman morals that such a guiding principal implies, but basically it boils down to being a geek and/or a hippie – advance technology as fast as possible and conserve natural resources so that the world doesn’t end before we reach the next level of technology. Thinking that somebody might hit the “stop” button on the entire simulation puts a new twist on the idea of the world ending because as a society we failed to reach a certain level of technological sophistication.
A Simulation Argument for Truth in Mathematical Beauty and Simplicity
If our world is a simulation running inside a massive computing device, then something must have programmed this simulation. The programmers of the simulation chose the physical laws that we live by, perhaps to see what would happen. This puts an interesting spin on evaluating fundamental physical laws. Which of these two equations below is more likely to be an accurate representation of the way the simulation designer wrote the code? These are two different mathematical representations of P.A.M. Dirac’s eponymous equation, which is AFAIK believed to be a completely accurate representation of our physical world.
By this logic, the second one is almost certainly closer to how the simulation programmer understood the concept. This perspective puts an interesting twist on Occam’s razor – the principal that the simpler explanation is probably true. My grandfather believed that the simpler a physical law was, the more likely it was to be correct. In this way he saw a certain beauty in math and physics. If our world exists only as a simulation, then the simpler a physical law is, the more likely it is to be an accurate representation of the way the simulation was coded.