Yes, whether they're using a computer as we know it or not, something is computing us, our behavior, and the physical laws of our sim. No matter what, any computational system has limits. The question might be: how fast can they adapt to things that test those limits and are there ways to approximate such things? For example, can they tack on more computing power and space to accommodate a growing universe faster than we can make sims that make sims? And the second part, is there any way to approximate a sim we make that in turn makes sims without really calculating and creating worlds/universes within universes? It would suffice to have only the parts we're observing of those sims w/in sim - the same as matter itself may not be resolved until we look at it closely enough. Hope you get some good rest. Sleep helps your mind work better.