If digital physics is true and physical reality consists of computations, then what could possibly be the computational platform, i.e. where could the computations be run on? What are possible answers explored in digital physics?
That question cannot, even in principle, be answered by experiment or the methods of empirical science. Thus, it has the same status as Phind's rhetorical question (which was, I expect, the point he making by asking it) and is out-of-scope for Physics Forums.Option (2) is interesting but of course very speculative. It stands or falls with the acceptability of mathematical platonism.