Reality is Ultimately Digital and its Program is still Undebugged

Reality is ultimately digital, and all the complexity we observe in the physical universe, from subatomic particles to the biosphere, is a mani- festation of the emergent properties of a digital computation that takes place at the smallest spacetime scale. Emergence in computation is an immensely creative force, whose relevance for theoretical physics is still largely underestimated. However, if the universe must be at all scien- tifically comprehensible, as suggested by a famous einsteinian quote, we have to additionally postulate this computation to sit at the bottom of a multi-level hierarchy of emergent phenomena satisfying appropriate re- quirements. In particular, we expect 'interesting things' to emerge at all levels, including the lowest ones. The digital/computational universe hy- pothesis gives us a great opportunity to achieve a concise, background independent theory, if the 'background' - a lively spacetime substratum - is equated with a finite causal set.