Is Everyone Probably Elsewhere?

Abstract It has been widely discussed whether the existence of other universes than known universe is a purely metaphysical consideration. This paper argues to contrary that meaningful hypothesis, which can be tested based on observable data. The applies perspective observer bias as an approach for assigning probabilities mutually excluding hypotheses vs. multiverse, i.e., only universe, or just one in ensemble universes, so-called multiverse. basic idea relies following In vast majority observers would live are more life friendly. Thus, conditional there being we should expect find ourselves with values fundamental parameters provide particularly fertile grounds life. contrast, if single it may well case still few even far from ideal life, and case, those will not intelligent that, among all parameter configurations allow at least somewhere, outnumber Based this elementary consideration, proceeds propose quantitative framework determine either hypothesis. particular, described how future ab initio determination some factors Drake equation used infer two likely. A end proposed. Expressing these context hypotheses, general likelihood first described. Then, support intuition, example computations provided, illustrating actual hypothesis test work practice.