Most physics treats mathematics as a description of nature. Digital physics takes a stranger position: that nature is not described by computation but is computation. Under this view the universe is not like a computer. It is one — a vast process that holds a state, applies rules, and produces the next state, over and over, with everything we call matter and motion emerging from the run.

The idea is older than modern computing. Konrad Zuse proposed it in the 1960s. Edward Fredkin built it out. Stephen Wolfram spent a career arguing that simple computational rules, iterated, can generate the full complexity of the physical world. The appeal is economy: instead of continuous fields described by infinite-precision numbers, you get discrete states and a rule that moves between them. Finite. Computable. Cheap.

The evidence is suggestive rather than decisive. Quantum mechanics is discrete where classical intuition expected smoothness. Information appears to be conserved and physical. There seems to be a smallest scale. None of this proves the universe is a computation. All of it is consistent with one.

The honest reading is that digital physics is a framework, not a result. But it reframes the simulation question usefully. If reality is already a computation, then "is it a simulation" stops being a question about whether reality is computed. It becomes only a question about who, if anyone, started the program.