Everything you have ever done or will do could simply be the product of a highly-advanced computer code. Every relationship, every sentiment, every memory could have been generated by banks of supercomputers.
This was the terrifying theory first proposed by British philosopher Nick Bostrom.
The shocking hypothesis was penned four years after Andrew and Lana Wachowski wrote and directed The Matrix, a film set in a dystopian future in which humans are subdued by a simulated reality.
In his paper, Dr Bostrom suggested a race of far-evolved descendants could be behind our digital imprisonment.
The futuristic beings - human or otherwise - could be using virtual reality to simulate a time in the past or recreate how their remote ancestors lived.
Sound crazy, right?
Well, it turns out some high ranking NASA scientists think Dr Bostrom might be onto something...