The strongest modern case for a simulated universe begins with an awkward fact: fundamental physics increasingly describes reality as information, not substance. Bekenstein showed that black-hole entropy scales with surface area rather than volume. From there, holographic duality, starting with Maldacena’s AdS/CFT correspondence and sharpened by Ryu and Takayanagi, showed that a gravitational spacetime can be represented by a lower-dimensional quantum system, with geometry tied directly to entanglement. Takayanagi’s 2025 review pushes the point further: gravitational spacetime can emerge from enormous numbers of entangled quantum bits. Once space itself can be encoded and reconstructed from information, calling the universe "physical" and calling it "computed" stop being opposites. [1]
The second step is computational capacity. Lloyd calculated that the observable universe can have registered about 10^90 bits and performed no more than about 10^120 elementary operations over its history. A universe with a finite bit budget and a finite operation budget looks far more like a bounded computation than an infinitely detailed continuum. Wolpert’s 2024 analysis goes further: under the physical Church-Turing thesis, the idea that physically realizable processes are computable, it is mathematically possible for us to be in a simulation, including a self-simulation. Modern science has not uncovered a computational impossibility here; it has uncovered a blueprint. [2]
Probability then stops this from being a mere curiosity. Bostrom showed that at least one of three things must be true: civilizations like ours almost always die before reaching technological maturity, mature civilizations almost never run large numbers of ancestor simulations, or observers like us are almost certainly simulated. If even a modest fraction of advanced civilizations survive and run such simulations, simulated observers will vastly outnumber biological originals. In that scenario, betting that we are in base reality is like betting that, in a library stuffed with copies, you are holding the unique first manuscript. Possible, yes. Rational, no. [3]
Most important, this idea has crossed into science because it touches observation. Beane, Davoudi, and Savage showed that a lattice-style simulated universe could leave detectable traces, including rotational-symmetry breaking in the highest-energy cosmic rays, and they derived a lower bound on the inverse lattice spacing from existing data. A sharper next test, extending their logic, would be to look for the same preferred symmetry across ultra-high-energy cosmic rays, neutrinos, and gravitational-wave backgrounds; if the same grid-like pattern appeared in all three, the case would become viciously strong. Put together, the evidence forms a coherent picture: spacetime behaves like encoded information, the universe has a finite computational budget, computer science allows self-simulation in principle, observer-counting strongly favors simulated minds, and physics offers possible detection channels. The strongest scientific inference is that reality is probably simulated and base reality is the exception, not the rule. [4]