What if reality isn’t real? Scientists think we might be living in a computer simulation

For us, the life we live feels very real. We know that the universe includes stars and planets, and on one of those planets, we live our lives normally. But physicists and philosophers have now raised a question about what we think is real. What if none of what we know is physical at all, and we're actually living inside an extremely advanced computer simulation?

This might sound like a story from science fiction, but this idea is being seriously debated in academic circles. Here’s why scientists believe our universe could be fake altogether.

Philosopher Nick Bostrom, who directs the Future of Humanity Institute at Oxford University, describes a simulated universe as a "richly detailed software simulation of people, including their historical predecessors, by a very technologically advanced civilization." 

His 'Simulation Argument' paper claims that there are three options, and at least one has to be true. It could be that every civilization goes extinct before it can build such simulations, every advanced civilization chooses not to build one, or we're actually already in it. He says that it only takes a single civilization anywhere in the cosmos to build simulations for them to multiply rapidly. According to this, we're statistically more likely to be inside one than not.

Adding to this idea, famous futurist Ray Kurzweil suggests that our universe already qualifies as a computer. This is because "physical laws are sets of computational processes" and "information is constantly changing, being manipulated, running on some computational substrate."  

He also joked that "maybe our whole universe is a science experiment of some junior high school student in another universe." Kurzweil describes himself as "a patternist," explaining, "I think patterns, which means that information is the fundamental reality."

Let’s say, for the sake of argument, that we are already inside a simulation. But how would we even know? For this, space scientist David Brin says that there might be some "back doors" left in the code. Cognitive scientist Marvin Minsky added that these can be noticed when the laws of physics aren’t quite right, or there are some mismatches in our reality. 

In an episode of Closer to Truth, Brin said, "If we are living in a simulation, then everything is software, including every atom in our bodies…and there may be 'back doors' that the programmers left ajar."

Martin Rees, U.K. Astronomer Royal, points out that scientists already simulate cosmic events on computers because they can't run real experiments on stars and galaxies. "We can't do experiments on stars and galaxies," Rees said, "but we can have a virtual universe in our computer, and calculate what happens if you crash galaxies together, evolve stars, etc." 

This raises the question of how much more we might be able to simulate as computing power keeps growing. "It's not crazy to believe that some time in the far future," he said, "there could be computers which could simulate a fairly large fraction of a world." Still, Rees is far less certain that something like human consciousness could ever be replicated by code.