Mathematical Universe Hypothesis

The mathematical universe hypothesis is the proposal, put forward by the Swedish-American cosmologist Max Tegmark, that the physical universe is not merely described by mathematics but is itself, in its entirety, a mathematical structure, so that physical existence and mathematical existence are the same thing. Tegmark first set out the idea in a 1998 paper and developed it further in later work, arguing that this would explain why the universe appears to run on precise mathematical laws: because the universe simply is one particular abstract mathematical object among the full space of possible ones. The hypothesis is closely tied to Tegmark's related proposal of a hierarchy of parallel universes, in which every mathematical structure that is logically self-consistent corresponds to some physically existing universe, our own being just one member of that vast ensemble. Critics have objected that the hypothesis is not falsifiable in the way ordinary scientific theories are expected to be, and that it is unclear how a mathematical structure alone, without any further physical ingredient, could give rise to subjective experience or the felt passage of time.