Any implementation of memory that's ever existed uses measurable physical quantities/states to represent information, not the other way around. Also, (in class

Any implementation of memory that's ever existed uses measurable physical quantities/states to represent information, not the other way around. Also, (in classical mechanics to keep it simple) it all comes down to position, momentum, and fields. E.g "size" and "composition" is determined by the positions of particles, etc. So in a way the answer to where those properties are stored is right there. If you don't think the universe can intrinsically have its own state, but it needs to be stored elsewhere, then there are a couple of issues. If this memory can only have the properties of the universe and no more, and can't be observed, it might as well not exist. If it has other possible states, then it's circular, and you'll need some memory one level up to store the state of the memory. So if you believe in nested simulations, I suppose your questions could be answered up to the "root" universe. Whether there is some "external" memory that actually stores all the state in the universe is at least for now pure metaphysics. Do you think anyone on Earth could possibly answer this question today?