"Elon Musk believes the universe is simulatable. It's just a matter of having the right inputs."
"Musk's comments are fascinating, in part because it highlights a particular worldview. Rather than scientific equations aiming to describe the world as observed, Musk suggests that there are knowable "true" equations that govern the universe waiting to be discovered. It's just a matter of finding the right ones."
Even if you would find the "true equations", and we might never find them, we might still not be able to solve them. Knowing equation doesn't mean we can solve it. Often we can only approximate solution.
Further from article:
Musk is not exactly alone in this: Robbert Dijkgraaf, director of the Institute for Advanced Study, explained in Quanta Magazine how Albert Einstein believed that there was a single, unique way to construct a functional universe. But Dijkgraaf also explained that the Standard Model of particle physics would suggest that the universe has a series of free parameters, ones that need to be measured in experiments, which "can be seen as the polar opposite of Einstein’s dream of a unique cosmos."
Concluding that there must be "series of free parameters" - that's a little strong statement. We might be estimating parameters only because we are going after the approximation of the solution rather than the exact solution.
While Musk was claiming that the universe could be simulated, he's claimed before that this reality is the simulation itself.
We might never be able to simulate exact universe even if we know equation, because solution is hard to find and we will be only improving its approximation. Also, do we really need to find the exact equation and the exact solution to it? Walt Whitman comes to rescue.
Walt Whitman: "Happiness, not in another place but this place... not for another hour, but this hour."