How likely are we to live in the REAL world and how many in a perfect computer simulation. According to the latest Matrix studies and reality have the same probabilities.

Man's thirst for knowledge has always led him to wonder about the nature of reality. Knowing is discovering reality, but what guarantees us that what we experience is really real and not just a simulation? It is a doubt that since ancient times has made its way into the mind of man, with Plato and his cave myth, or even with the Cartesian "evil genius", also inspiring novels with dreamlike nuances such as Lewis Carrol's Alice Adventures and finally finding space in mass cinematography in works such as The Truman Show or the more sci-fi Matrix.

The theme was also addressed by the contemporary philosopher Nick Bostrom who in 2013 published an essay in which he explored the possibility that the reality we live daily is a computer simulation recreated by a society more advanced than ours. Bostrom in particular focused on the fact that of the following three hypotheses, at least one should be the real one:

A civilization dies out before developing the ability to create simulations of reality.

An advanced civilization has no interest in creating simulations of reality.

We're almost certainly living within a computer simulation.
Finally, more recently, the visionary entrepreneur Elon Musk also touched on the subject when, during a press conference in 2016, he said perhaps a little superficially that "the chances that we are in the basic reality are one in the billions".

It is instead of these days a speech by the astronomer David Kipping of Columbia University who returns to the subject on Scientific American raising some doubts about Musk's statement and taking the opportunity to offer his vision on a topic that continues to tickle the deep thought and imagination of man.

"Musk is right if the first two trilemma hypotheses are assumed to be false, but how can this be assumed?" asks Kipping. The astronomer then decided to reconsider Bostrom's "trilemma" with a Bayesian approach, i.e. calculating the probability of a thing happening (ex-post probability) making the first hypothesis about the analyzed thing (assigning an ex-ante probability).

"It is sufficient to assign an ex-ante probability to each of these two hypotheses. We assume the principle of indifference, which is the default assumption when you do not have data or inclinations for the hypotheses that arise": with this reasoning Kipping simply means that apriorily the two hypotheses have equal probability of being true.

Kipping's reasoning then continues to consider the realities "pluripare" from those "nullipare": the first, that is, that can generate other simulated realities and the latter instead of that can not create any simulation. If we were to actually take the first of the two hypotheses (there is no simulation), then the probability of living in a nulliparous universe would be easy to calculate and would be 100%. However, Kipping then showed that even if you lived in a simulation, most of the simulated realities would be null and void, because when the simulations stratified, at the same time the resources available to a hypothetical computer used for simulation would decrease.

In other words, the deeper you go into the "hawthorn lair", the less computing power you would have available to create a convincing simulation. This is to say that even if we lived in a simulation, we would most likely perceive it as a nullipara reality. But if the reality is nullipara and even the simulation has a high probability of being nullipara, then according to Kipping there are no elements that can suggest for one or the other hypothesis and therefore even the ex-post probabilities of living in the basic reality are almost equal to the probabilities of living in a simulation.

But if civilization could create a simulation with conscious beings within it, the odds would change dramatically. "The first of the two hypotheses can simply be ruled out immediately, so only the simulation hypothesis remains. When we invent that technology, the odds of 50-50 are unbalanced towards the hypothesis that we live in a simulation. That day would be a very strange celebration of our genius."

So downstream of Kipping's reasoning, Musk would be misled about the chances of one in billion living in basic reality. Bostrom also agrees with Kipping's result, but disputes the decision to assign equal probabilities to the two hypotheses at the beginning of the reasoning: "Invoking the principle of indifference in this case is a gamble. My three originaire hypotheses could be considered just as well, with a third of the probability of each. Or you could carve out the space of possibilities in any other way and get whatever result you want."