Existential relativism: As a potential solution, Sosa advances existential relativism. The central claim is that objects do not exist objectively as if some "supervenient entities [. . . objectively supervene on their requisite constitutive matters and forms." On existential relativism, composition is relative to a conceptual scheme. Conceptual schemes are mental collections of ideas of how the world exists and interacts. They can differ based on language, culture, personal utility, perspective, etc. A person's conceptual scheme helps select the things in the external world that resemble these mental ideas and then confers existence on them. Since conceptual schemes can differ, different persons may recognize different objects. Conceptual schemes are chosen based on how useful they are to the individual in understanding the world.