 Bechtel and Mundale (1999) note that proponents of multiple realizability often appeal to different amounts of “granularity” in how they individuate mental versus neurobiological kinds. Proponents often analyze psychological states at a coarse-grained level, in which only the loosest input-output similarities across species are deemed sufficient for mental kind identities. Yet they insist on very fine-grained individuation for brain states, in which small differences across species are sufficient for neural type-differences. But psychological ascriptions admit of finer grains and neural ascriptions admit of coarser grains. Bechtel and Mundale insist that when a common grain is chosen for both, mental-neural type-identities holding across species are found.