Are you real? What about me?

These used to be questions that only philosophers worried about. Scientists just got on with figuring out how the world is, and why. But some of the current best guesses about how the world is seem to leave the question hanging over science too.

Several physicists, cosmologists and technologists are now happy to entertain the idea that we are all living inside a gigantic computer simulation, experiencing a Matrix-style virtual world that we mistakenly think is real.

Our instincts rebel, of course. It all feels too real to be a simulation. The weight of the cup in my hand, the rich aroma of the coffee it contains, the sounds all around me – how can such richness of experience be faked?

But then consider the extraordinary progress in computer and information technologies over the past few decades. Computers have given us games of uncanny realism – with autonomous characters responding to our choices – as well as virtual-reality simulators of tremendous persuasive power.

It is enough to make you paranoid.

The Matrix formulated the narrative with unprecedented clarity. In that story, humans are locked by a malignant power into a virtual world that they accept unquestioningly as “real”. But the science-fiction nightmare of being trapped in a universe manufactured within our minds can be traced back further, for instance to David Cronenberg’s Videodrome (1983) and Terry Gilliam’s Brazil (1985).

Over all these dystopian visions, there loom two questions. How would we know? And would it matter anyway?

Elon Musk, CEO of Tesla and SpaceX (Credit: Kristoffer Tripplaar/Alamy)

The idea that we live in a simulation has some high-profile advocates.

In June 2016, technology entrepreneur Elon Musk assertedthat the odds are “a billion to one” against us living in “base reality”.

Similarly, Google’s machine-intelligence guru Ray Kurzweil has suggested that “maybe our whole universe is a science experiment of some junior high-school student in another universe”.

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