Are we living in a computer simulation?

If you could change the laws of nature, what would you change? Maybe it’s that pesky speed-of-light limit on cosmic travel — not to mention war, pestilence and the eventual asteroid that has Earth’s name on it. Maybe you would like the ability to go back in time — to tell your teenage self how to deal with your parents, or to buy Google stock. Couldn’t the universe use a few improvements? That was the question that David Anderson, a computer scientist, enthusiast of the Search for Extraterrestrial Intelligence (SETI), musician and mathematician at the University of California, Berkeley, recently asked his colleagues and friends.

In recent years the idea that our universe, including ourselves and all of our innermost thoughts, is a computer simulation, running on a thinking machine of cosmic capacity, has permeated culture high and low. In an influential essay in 2003, Nick Bostrom, a philosopher at the University of Oxford and director of the Institute for the Future of Humanity, proposed the idea, adding that it was probably an easy accomplishment for “technologically mature” civilizations wanting to explore their histories or entertain their offspring. Elon Musk, who, for all we know, is the star of this simulation, seemed to echo this idea when he once declared that there was only a one-in-a-billion chance that we lived in “base reality.”

It’s hard to prove, and not everyone agrees that such a drastic extrapolation of our computing power is possible or inevitable, or that civilization will last long enough to see it through. But we can’t disprove the idea either, so thinkers like Dr. Bostrom contend that we must take the possibility seriously. In some respects, the notion of a Great Simulator is redolent of a recent theory among cosmologists that the universe is a hologram, its margins lined with quantum codes that determine what is going on inside. A couple of years ago, pinned down by the coronavirus pandemic, Dr. Anderson began discussing the implications of this idea with his teenage son. If indeed everything was a simulation, then making improvements would simply be a matter of altering whatever software program was running everything. “Being a programmer, I thought about exactly what these changes might involve,” he said in an email.

If the software was well written, tweaking it should be easy work, he reasoned. Modifications could change our laws of physics, or add new features to the universe: menu options, speed filters, closed captioning, pop-up blockers — buttons to push that would make our lives richer or more fun. Moreover, if the software running the universe was open source — publicly available for other programmers to inspect and manipulate — then these “meta-hackers” might be amenable to our feature requests, and might even be looking for them, Dan Werthimer, Dr. Anderson’s colleague in Berkeley, suggested. Think of it as a cybernetic version of prayer, a way to petition the Great Simulator.

Dr. Anderson recently polled his colleagues to ask how they would tweak the cosmic algorithm, which he calls Unisym. He posted the responses on his blog, along with comments on how these changes might be put in effect and how well they might work.

“This was during Covid, when I was filling my ample free time by writing various essays on philosophy, politics and music and putting them on my website,” he said. The emphasis was not on eliminating war and injustice but on features that might help us cosmic small fry to navigate the vicissitudes of “life.”

For example, Dr. Anderson would like to be able to click a button and view all of the footsteps he has ever taken, glowing orange on the ground. “I can see where I’ve been in Berkeley and go to the Sierras and I can see all the hikes I’ve taken there,” he said. Clicking another button would highlight all of the footprints ever made. “Are there places no one has ever been?” he wondered. His son, he added, would like to know if a joke he was about to tell would get a good laugh.

Some feature requests from his other respondents: the ability to pause the simulation long enough to think up a snappy retort in conversation, or a rewind option to undo a regrettable remark or revisit a missed opportunity, something I would definitely up-vote.

Simple as these requests may sound, Dr. Anderson noted, using such features might require a fair bit of computational engineering behind the scenes. For instance, briefly pausing the universe to collect your thoughts would require branching your own existence into a temporary parallel simulation; then, when you knew what you wanted to say, you could hit the escape key and revert to the original simulation. Rewinding to correct the past would also cause the simulation to branch, but in this case, Dr. Anderson said, you would continue in the parallel simulation “and never hit escape.”

Of course, he added, “the usual time-travel weirdness applies.” Stepping into the future and returning would endow your present self with memories of things that hadn’t happened yet. This, in turn, would change the future, such that when you got there it wouldn’t be quite what you had remembered from your first visit.

Likewise, stepping into the past could alter what you remembered happening in the future. It might even obviate your own existence, as with the time traveller in Ray Bradbury’s classic story “A Sound of Thunder” who steps on a butterfly and returns to a future in which the Nazis run the world. (Or, as with Homer in the “Time and Punishment” episode of “The Simpsons,” who inadvertently creates a world unfamiliar with doughnuts.) Apparently, time travel is about the most dangerous thing you can do.

For my part, I’d like to be able to hit a button upon entering a restaurant that would drop a cone of silence over every other table. (My hearing isn’t what it used to be.) My wife said she would like for a hologram of her to appear whenever she was late to some appointment, and then disappear when she actually arrived, so that nobody would know she had been absent.

A popular modification is what Dr. Anderson calls “the look of death,” the ultimate expression of road rage: With a blink of your eyes, you could doom offending drivers and their cars to be incinerated by a powerful laser. “Each such request should fork a new universe, for obvious reasons,” Dr. Anderson writes on his blog. “It’s a safe bet that someone would give me the look of death within a day or two,” he writes. “And within a few weeks nearly all drivers would be incinerated. So it’s probably best to implement this so that each look of death forks a new universe where the requested incineration happens, but the original universe continues without it.” What’s on your cosmic wish list? How would you tweak the supreme algorithm? The year 2023 is still young; there’s plenty of time to petition the cosmic hackers for a better deal. Just look out for the butterflies, and be careful what you wish for.