on the most fundamental level there exists only one thing: the world as a whole. This thesis doesn't deny our common-sense intuition that the distinct objects we encounter in our everyday affairs like cars or other people exist. It only denies that these objects have the most fundamental form of existence. Comparison According to Schaffer, an important difference between the two approaches is that the Quinean approach leads to a flat ontology while the neo-Aristotelian approach leads to an ordered ontology. In a flat ontology, there is no difference in fundamentality between the different objects: they are all on the same level. In an ordered ontology, on the other hand, the entities are part of a complex hierarchical structure with different levels. The higher levels of this structure are grounded in the more basic levels. Schaffer also distinguishes a third type of ontology which he calls sorted. Sorted ontologies classify entities into different exclusive ontological categories. But this classification doesn't entail any hierarchical relations between the entities of the different categories. It has been argued that neo-Aristotelianism is not a genuine alternative to Quineanism. So theories in ontology may combine elements from both approaches without becoming inconsistent. Anti-realism The meta-ontological anti-realist holds that there are no objective answers to the basic questions of ontology. One example of such an approach is Rudolf Carnap's thesis that the truth of existence-claims depends on the framework in which these claims are formulated. The choice between frameworks is guided by pragmatic considerations but there is no definite fact about which framework is correct. Quine disagreed with his teacher Carnap on these points, which lead to the Carnap-Quine debate. Amie L. Thomasson summarizes the disagreement underlying this debate with reference to the distinction "between existence questions asked using a linguistic framework and existence questions that are supposed to be asked somehow without being subject to those rules—asked, as Quine puts it 'before the adoption of the given language'." Carnap refers to this distinction as the internal-external distinction. See also Grounding (metaphysics) Metametaphysics Metaphilosophy References Further reading Chapter 2: Composition, Colocation and Metaontology" (Karen Bennett); Chapter 6: The Metaonology of Abstraction (Bob Hale, Crispin Wright) To be published in Ontology after Carnap Stephan Blatti & Sandra Lapointe (eds.) External links PhilPapers metaontology Scholarly papers on metaontology David Chalmers: Ontological Anti-Realism Cian Dorr: What We Disagree About When We Disagree About Ontology The connection of meta-ontology to