The universe is a computer, and time is the process of it running. This is the core claim that Stephen Wolfram has been developing for more than four decades, and in a recent interview with New Scientist, the physicist and computational thinker made his most accessible case yet.
“Time is the irreducible doing of computation,” Wolfram told New Scientist’s Leah Crane. “What we perceive as time is our experience of the process of the universe computing its successive states.”
Time, in this view, is not a fundamental background coordinate against which events unfold. It is not a dimension of spacetime in the conventional sense. It is something generated by the ongoing, stepwise execution of the universe’s state from one moment to the next. Wolfram uses a flipbook analogy: each page is a state of the universe, and you must physically turn each page to see the motion, and you cannot jump to the last page and know what happened in between.
The pi principle
The reason you cannot jump ahead, Wolfram argues, is a phenomenon he calls computational irreducibility. First identified in the early 1980s during his work on cellular automata, it describes systems for which there is no shortcut formula, no way to determine the outcome of N steps without explicitly simulating each of those steps.
“You can’t calculate the 1200th digit of pi on its own,” Wolfram explained. “You have to calculate the first 1199 digits first.”
This is fundamentally different from classical physics, where equations like Newton’s laws allow you to plug in a time value t and directly compute any future state. Under computational irreducibility, many natural systems have no such shortcut. The only way to know what happens is to let it happen.
Why we can’t time-travel
If the universe’s evolution is an irreducible computation, time travel becomes categorically impossible. Jumping to an earlier or later point in time would require shortcutting the computation, running it out of order or skipping steps, which is mathematically forbidden.
Wolfram’s argument extends to prediction as well. “Any computer we build is made of matter inside the universe. It cannot run faster than the universe itself computes,” he said. This places a fundamental limit on what can be predicted: a sufficiently complex system (the weather, the economy, the human brain) cannot be fully simulated in advance because no simulator inside the universe can outrun the universe’s own computation.
Free will in a determined universe
The most provocative implication involves free will. Wolfram’s universe is deterministic; each state rigidly determines the next according to fixed rules. But because the computation is irreducible, even a fully determined system feels unpredictable to us.
“Because of computational irreducibility… if we could always predict what we’re going to do a year in the future, then we wouldn’t imagine that it’s up to us to figure out what we do,” Wolfram said. “We would just be sitting here as passengers.”
He elaborated in his 2002 book A New Kind of Science: “If the evolution of a system corresponds to an irreducible computation, then this means that the only way to work out how the system will behave is essentially to perform this computation, with the result that there can fundamentally be no laws that allow one to work out the behavior more directly. And it is this, I believe, that is the ultimate origin of the apparent freedom of human will.”
If we had truly random free will with no underlying laws, Wolfram noted, science would be impossible. “The fact that science works implies underlying laws, but computational irreducibility preserves the feeling of free will.”
A theory without experimental predictions
The interview, part of New Scientist’s Lost in Space-Time newsletter series, draws on Wolfram’s essay “On the Nature of Time” (October 2024) and the broader Wolfram Physics Project, which he announced in 2020. It arrives just weeks after a separate experimental demonstration by Giovanni Barontini at the University of Birmingham, who built a Bose-Einstein condensate “mini-universe” to show that time can emerge from entropy exchange between quantum systems. Wolfram’s approach is theoretical rather than experimental: he offers a metaphysical framework, not a testable hypothesis.
This remains the central criticism of Wolfram’s project. MIT physicist Daniel Harlow, commenting on the Wolfram Physics Project in 2020, told Scientific American: “The experimental predictions of quantum physics and general relativity have been confirmed to many decimal places, in some cases, to a precision of one part in 10 billion. So far I see no indication that this could be done using the simple kinds of computational rules advocated by Wolfram. The successes he claims are, at best, qualitative.”
Wolfram’s interview includes no direct response to such criticisms. The piece is structured as a Q&A that gives him the floor.
Sources
1. New Scientist, “Does time come from the entire universe running computations?” (7 July 2026). https://www.newscientist.com/article/2532871/does-time-come-from-the-entire-universe-running-computations/
2. Wolfram, S., “On the Nature of Time” (Wolfram Media ePubs, October 2024). https://writings.stephenwolfram.com/2024/10/on-the-nature-of-time/
3. Wolfram, S., A New Kind of Science (Wolfram Media, 2002).