Theoretical physicist Sabine Hossenfelder does not like the notion that we are living in a giant computer sim. Elon Musk likes it (“Elon Musk says there’s a ‘one in billions’ chance reality is not a simulation”) and so does Neil deGrasse Tyson (“Neil deGrasse Tyson says it’s ‘very likely’ the universe is a simulation”). Philosopher of science Nick Bostrom advanced that view in a seminal 2003 paper in Philosophical Quarterly. Former Astronomer Royal Martin Rees is sympathetic to it. Some call it the Planetarium hypothesis, when it is cited as a reason we do not see intelligent extraterrestrials.
We can probably all think of reasons for doubt but Hossenfelder has put some thought into a response. Some of her approaches work better than others.
First, she says, the simulation hypothesis assumes a superintelligent being, which amounts to “mixing science with religion, which is generally a bad idea.” The difficulty is, if there is evidence that a superintelligent being does exist, awareness of that being’s effects — whatever they are — cannot simply be discarded as “religion.” In that case, the being and the effects are just a fact, and science can make what it likes of the fact.
She doesn’t think that the difficulty of simulating human consciousness is a good argument against the simulation hypothesis because
… for all we currently know, consciousness is simply a property of certain systems that process large amounts of information. It doesn’t really matter exactly what physical basis this information processing is based on. Could be neurons or could be transistors, or it could be transistors believing they are neurons. So, I don’t think simulating consciousness is the problematic part.Sabine Hossenfelder, “The Simulation Hypothesis is Pseudoscience” at BackRe(Action)
Actually, human consciousness is, generally speaking, still a complete mystery, termed politely the The Hard Problem of consciousness. Whether it could be simulated is a “problematic part.” But no need to quibble. Hossenfelder moves on to more interesting, computer-based reasons for doubt. Computers, after all, are a subject we can really know something about:
Some, like Oxford philosopher Nick Bostrom, assume that it is possible to reproduce the laws of physics on a machine. But, she says,
… nobody presently knows how to reproduce General Relativity and the Standard Model of particle physics from a computer algorithm running on some sort of machine. You can approximate the laws that we know with a computer simulation – we do this all the time – but if that was how nature actually worked, we could see the difference. Indeed, physicists have looked for signs that natural laws really proceed step by step, like in a computer code, but their search has come up empty handed. It’s possible to tell the difference because attempts to algorithmically reproduce natural laws are usually incompatible with the symmetries of Einstein’s theories of special and general relativity… The bottomline is, it’s not easy to outdo Einstein.Sabine Hossenfelder, “The Simulation Hypothesis is Pseudoscience” at BackRe(Action)
Apparently, quantum computers wouldn’t help because we would face the same problem. An even bigger problem is how the simulated universe is supposed to work, if it includes a large number of humanly conscious beings (seven billion on this planet alone) who may themselves try to simulate conscious beings. Bostrom appears to think that the great simulator can just fill in the blanks when problems arise. But Hossenfelder asks:
What kind of computer code can actually do that? What algorithm can identify conscious subsystems and their intention and then quickly fill in the required information without ever producing an observable inconsistency. That’s a much more difficult issue than Bostrom seems to appreciate. You cannot in general just throw away physical processes on short distances and still get the long distances right.Sabine Hossenfelder, “The Simulation Hypothesis is Pseudoscience” at BackRe(Action)
She uses some interesting facts from climate change studies as an illustration of the problem.
Computers probably can’t handle a simulated universe because, for one thing, much human thinking is non-computational, which means it is something computers can’t, by definition, do. Neurosurgeon Michael Egnor puts it like this:
Computation is syntax, whereas thought is semantics. If we were living in a computer simulation, and our mind were computation, the one thing we couldn’t do is think.
We couldn’t ask the question “Are we living in a computer simulation?” if we were living in a computer simulation. The irony here is that, of all the possible fundamental truths of reality, the notion that we are living in such a simulation is the one we can rule out simply because it’s self-refuting.Michael Egnor, “Of Course You Aren’t Living in a Computer Simulation. Here’s Why.” at Evolution News and Science Today
Perhaps the most significant fact of this debate is that so many thinkers are talking about the fact that our universe looks designed:
The main point here is that the “simulation hypothesis” shows that the possibility that the universe was intelligently designed is increasingly a serious topic of conversation among scientists and other respected thinkers. A recent article by Jack Butler at National Review covers a new documentary, A Glitch in the Matrix, which provides a “fair and evenhanded” treatment of the simulation hypothesis.Casey Luskin, ““Simulation Hypothesis” and Star Trek — Intelligent Design by Another Name” at Evolution News and Science Today
In Star Trek Q & A (2019), the young Dr. Spock contemplates the idea that the universe is designed, thinks it is reasonable, and then asks “Am I becoming an annoyance?”
Maybe, but it is an annoyance we may need, in order to understand our world better.
Sabine Hossenfelder often raises and responds to very interesting questions:
A theoretical physicist asks, was the universe made for us? She says no. But the question is more complicated than it appears at first. It is true that we have only one universe to go by but then each of us is a unique individual too. What if you had an experience no one else has had?
A theoretical physicist grapples with the math of consciousness Looking at the various theories, she is not very happy.
Can physics prove there is no free will? No, but it can make physicists incoherent when they write about free will. Sabine Hossenfelder insists that people must change their minds and realize that there is no free will even though, according to her theory, that is just what they cannot do. (Michael Egnor)