Materialism is an ontological position which holds, despite evidence to the contrary, that there is no immaterial or spiritual realm. Only things which are detectable in some form by the senses and sense experience- for instance forks, matter, radiation, heat, neutrinos, mayonnaise, galaxies, and so forth. It assumed by the position of empiricism, and therefore science, and is contrasted with substance dualism and immaterialism. Arguments for materialism commonly employ ontological principles such as Occam's Razor- as an immaterial realm is wholly superfluous to materialists' understanding of the world, they have no reason to believe it exists.