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 traveler 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.
