A Computer Scientist's View of Life, the Universe, and Everything

Is the universe computable? If so, it may be much cheaper in terms of information requirements to compute all computable universes instead of just ours. I apply basic concepts of Kolmogorov complexity theory to the set of possible universes, and chat about perceived and true randomness, life, generalization, and learning in a given universe. Preliminaries Assumptions. A long time ago, the Great Programmer wrote a program that runs all possible universes on His Big Computer. \Possible" means \com-putable": (1) Each universe evolves on a discrete time scale. (2) Any universe's state at a given time is describable by a nite number of bits. One of the many universes is ours, despite some who evolved in it and claim it is incomputable. Computable universes. Let TM denote an arbitrary universal Turing machine with unidirectional output tape. TM's input and output symbols are \0", \1", and \," (comma). TM's possible input programs can be ordered alphabeti-A k denote TM's k-th program in this list. Its output will be a nite or innnite string over the alphabet f \0",\1",\,"g. This sequence of bitstrings separated by commas will be interpreted as the evolution E k of universe U k. If E k includes at least one comma, then let U l k denote the l-th (possibly empty) bitstring before the l-th comma. U l k represents U k 's state at the l-th