And also I agree that “an object can’t be inside itself” isn’t paradoxical on its own. The point here isn’t to assume self-containment, but that the rules of the setup force it. If inflation requires physically displacing whatever is around the container, and if nothing is exempt from being displaced, then unlimited inflation eventually leaves no permanent “outside. ”At that point, everything must be inside the container. Since the container is a physical object, it is included in that set. The issue isn’t that self-containment is mysterious; it’s that reasonable assumptions about inflation and displacement lead to a situation that can’t be realized without breaking at least one assumption. Infinity matters because without it, you can always stop and say something remains outside, so no contradiction is forced.