It’s easy to prove "we don’t know that" since maybe it is possible to introspect our universe. For example, suppose someone interacts with some quantum system a

It’s easy to prove "we don’t know that" since maybe it is possible to introspect our universe. For example, suppose someone interacts with some quantum system and it unexpectedly outputs a binary string. It turns out that this string can be interpreted as a command-line interface where one can access the states of individual particles and inspect the running process. Given the program code of our universe is reasonably short, we could possibly fully understand the system from within.