When the sci-fi film "The Matrix" first hit theaters back in 1999, it inspired a whole new generation of amateur philosophers to ponder whether the world really is as it appears. In the film, sentient machines have subdued humanity by plugging everyone's brains into a sophisticated computer network that convinces them to believe in a simulated reality.

The film is a play on a philosophical conundrum as old as philosophy itself: How can we know whether the world really is how we perceive it to be?

Now a group of physicists led by Silas Beane of the University of Washington think they have accomplished what centuries of philosophy could not, according to Discover. They believe they have discovered a solution to this age-old mystery. Or at least, they believe they have devised a test that can determine, once and for all, whether we live in a computer simulation like the one in "The Matrix" or not.

Their proposed experiment has been deemed the "cosmic ray test." It assumes that any simulation of the universe would need to be constructed out of a lattice, or grid, much as television images are built from pixels. The researchers then calculated that such a simulation would require that the fastest particles — or cosmic rays — would always bombard the Earth with a maximum energy amount.

Beane and colleagues surmise that if we do indeed observe a maximum energy amount for the cosmic rays that bombard the Earth, that this should provide confirmation that we really are living in a simulation. (In case you're wondering, this is what has been observed: cosmic rays always arrive at Earth with a specific maximum energy of about 1020 electron volts.)

So does that decide it then? Is Beane's experiment proof that we're living in a simulated universe? Beane himself doesn't think it matters one way or another: "Learning we live in a simulation would make no more difference to my life than believing that the universe was seeded at the Big Bang," he suggested. To him, the issue is a mere scientific curiosity.

Philosophers aren't likely to be so easily sated, however. Beane's test makes a lot of unnecessary assumptions. For instance, it assumes that any simulation of the universe would need to be constructed from a lattice or grid. Perhaps our supergenius simulator overlords have discovered some more advanced way of constructing a simulation.

Beane's test also can't rule out the possibility that the universe might actually happen to function like a latticed simulation. In other words, it's possible that reality and simulated reality are simply perceptively indistinguishable. If such were the case, then no test would suffice. We'd be right back at square one — a place where the scientist must, incontrovertibly, give way to the philosopher.

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