Meta-ontology is the metatheory of ontology, which is to say it comprises discussion of what ontology is about and its methods. According to Hofweber:
|‘||"it also isn't so clear what an ontological question really is, and thus what it is that ontology is supposed to accomplish. To figure this out is the task of meta-ontology, which strictly speaking is not part of ontology construed narrowly, but the study of what ontology is. However, like most philosophical disciplines, ontology more broadly construed contains its own meta-study, and thus meta-ontology is part of ontology, more broadly construed. Nonetheless it is helpful to separate it out as a special part of ontology. Many of the philosophically most fundamental questions about ontology really are meta-ontological questions."||’|
- ——Thomas Hofweber; Logic and ontology
The term 'meta-ontology' is rather new and became more used following a paper titled 'Meta-ontology' by Peter van Inwagen. He phrased the subject of 'meta-ontology' as follows:
|‘||Quine has called the question ‘What is there?’ "the ontological question." But if we call this question by that name, what name shall we use for the question, ‘What are we asking when we ask “What is there?” ’? Established usage, or misusage, suggests the name ‘the meta-ontological question’, and this is the name I shall use."||’|
- ——Peter van Inwagen; Meta-ontology
The question by Quine that Inwagen is referring to was posed in an essay On what there is.
The questions Inwagen referred to as 'meta-ontology' concerned a debate between Carnap and Quine about the structure of an ontology. So a logical starting point is the position of Carnap, followed by the critique by Quine, and then some more modern takes on the issues.
Carnap came from the school of logical positivism which was an outgrowth of some impatience of scientists with philosophy. Carnap's view was that an ontology consists of two parts: an 'internal' part and an 'external' part. The internal part consists of a logical combination of terms, definitions and formal relationships, and the observational data that the logical part intended to explain. He called this a 'linguistic framework'. The 'external' part consists of pragmatic or practical considerations about which framework to use. Carnap felt that the 'linguistic framework' was not interesting to philosophers because any analysis of this part amounted simply to questions about usage of terms. On the other hand, Carnap felt that the 'external' part was not interesting to philosophers either, because it turned upon merely practical matters, such as how accurate a description was useful, whether a specific linguistic framework was pertinent to a particular practical problem, and so forth.
His views were expressed in two major works: Meaning and necessity in which he presented the idea of the analytic-synthetic distinction, and Empiricism, Semantics, and Ontology in which he presented the internal-external distinction. The internal-external distinction has been described. The analytic-synthetic distinction was a separation between terms that were defined, analytic terms whose meaning was specified by the logical part of a linguistic framework, and synthetic terms whose meaning involved some empirical observation. An example of the analytic type that is very often presented is All bachelors are unmarried. An example of the synthetic type requiring some evidential input is John is a bachelor.
Quine critiqued Carnap's views in several major works. Possibly the most direct critiques are On Carnap's views on ontology and Two dogmas of empiricism. He first dismissed the 'internal-external distinction' as just a matter of how general a terminology one chose to use. So for example, one could choose a language that employed the category furniture, in which case one could talk about the subclasses tables and chairs and beds, or one could choose to use a narrower language in which furniture was not a concept, and chairs was the category. In that case one was restricted to speak of the subclasses of types of chair: arm chairs, lawn chairs and so forth; the choice of language being just a matter of convenience. A 'category question' would then be whether to use the language employing the concept of 'furniture' or the one invoking only 'chairs'. The 'external' questions of Carnap were viewed by Quine as simply these category questions, a matter of mere convenience, and essentially trivial. By simply choosing a more-encompassing language the existence of 'chairs' that appears problematic in the language involving only 'chairs', becomes simply a subclass question in the broader language that describes 'furniture'.
|‘||“It begins to appear, then, that Carnap’s dichotomy of questions of existence is a dichotomy between questions of the form “Are there so-and-so’s?” where the so-and-so’s purport to exhaust the range of a particular style of bound variables, and questions of the form “Are there so-and-so’s?” where the so-and-so’s do not purport to exhaust the range of a particular style of bound variables. Let me call the former questions category questions, and the latter ones subclass questions. ... The external questions are the category questions conceived as propounded before the adoption of a given language; and they are, Carnap holds, properly to be construed as questions of the desirability of a given language form. The internal questions comprise the subclass questions and, in addition, the category questions when these are construed as treated within an adopted language as questions having trivially analytic or contradictory answers.”||’|
—Willard Quine, On Carnap's views of ontology
This aspect of Quine's critique is not widely accepted today, as is discussed later. It basically ignores the possibility that the relations between terms can be quite different in the different languages, for instance, what grounds what? As an example, the choice between planar geometry and spherical geometry is not just a question of a more or less inclusive vocabulary.
By dropping the 'internal-external' distinction, Quine reduced Carnap's structure for an ontology to simply the 'analytic-synthetic distinction' and he proceeded to argue that this division was untenable, that any attempt to define 'analyticity' inevitably was either completely circular and meaningless or dragged in some empirical aspect that made the supposedly analytic actually synthetic. The problem is that any explanation of a analytic statement that is more than just a restatement in terms of defined synonyms, that is, any explanation that is not circular, is a statement about usage, and any non-circular approach to usage inevitably draws in a context that invokes empirical matters. Quine's approach to this issue also has been questioned, as discussed later, but it is a much more subtle matter than it appears. There is some doubt whether Carnap actually would dispute this matter, which he would see as an internal question about the connection between the observational and the logical structure of a particular linguistic framework.
In any event, in Quine's meta-ontological view, there is one all-encompassing ontology that includes all possible subdivisions made for practical convenience and entertains no analytic-synthetic partition. Price calls this "Quine's move to homogenize the existential quantifier" and an argument for monism. Monism is in contrast to pluralism and asserts the unity of reality, although there are differences between monists over just how this unity is expressed.
It has been said that Quine is important not for settling matters but for providing the tools for discussion. Inwagen referred specifically to Quine's elaborate technique for uncovering just what basic items a theory required for its construction, be that explicit or only implied; the various 'such-and-such' used in expressions like there is at least one such-and-such. Quine referred to these objects and the connections between them as the 'ontological commitment' of the theory.
Wittgenstein also felt that the division of reality into narrow independent linguistic frameworks for special purposes was artificial, but differed from Quine in thinking that there was no over-arching, single, fundamental ontology, but only a patchwork of overlapping interconnected ontologies inextricably leading from one to another.
The evolution of the analytic-synthetic distinction can be found in Ryan. Here the development of the internal-external distinction is examined. The separation of this matter from the analytic-synthetic distinction is discussed elsewhere.
The upshot of the assessment of the internal-external distinction is often called a 'deflationary' meta-ontology, that is, a view that ontology has not much to say about 'what exists?', that this question is answered by science and the scientific approach to 'reality'. Rather, ontology is properly concerned with clarifying a scientific theory as to its consistency, its posited internal relations, and its usage of terms. The basic view is that of Carnap, namely, to “replace the ontological theses about the reality or irreality of certain entities [expressed in answer to external questions], theses which we regard as pseudo-theses, by proposals or decisions concerning the use of certain languages. Thus realism is replaced by the practical decision to use the reistic [thing-] language, [and] phenomenalism by the decision to use only the phenomenal language, …, and so forth.” [italics added] This view is called 'easy ontology' by Thomasson.
- Thomas Hofweber (Aug 30, 2011). Edward N. Zalta, ed:Logic and ontology. The Stanford Encyclopedia of Philosophy (Spring 2013 Edition).
- Peter van Inwagen (1998). "Meta-ontology". Erkenntnis 48: 233–250. reprinted in Peter van Inwagen (2001). “Chapter 1: Meta-ontology”, Ontology, Identity and Modality, paperback. Cambridge University Press. ISBN 0521795486. On-line version found here.
- Willard van Orman Quine (September, 1948). "On what there is". Review of metaphysics 2: p. 21 ff. Reprinted in Willard van Orman Quine (1980). “Chapter 1: On what there is”, From a logical point of view, 2nd. Harvard University Press. ISBN 0674323513. On-line version is found here.
- Rudolf Carnap (1946). Meaning and Necessity: A study in semantics and modal logic. Chicago University Press.
- Rudolf Carnap (1950). "Empiricism, Semantics, and Ontology". Revue Internationale de Philosophie 4: 40-50.
- Willard van Orman Quine (October, 1951). "On Carnap's views on ontology". Philosophical Studies II: 65 ff. Reprinted in W v O Quine (1976). “Chapter 19: On Carnap's views on ontology”, The ways of paradox: and other essays, 2nd. Harvard University Press, 203 ff. ISBN 0674948378.
- Willard Van Orman Quine (1980). “Chapter 2: Two dogmas of empiricism”, From a Logical Point of View: Nine Logico-philosophical Essays, 2nd. Harvard University Press, 20 'ff. ISBN 0674323513. See this on-line version.
- Stephen Yablo (1998). "Does ontology rest upon a mistake?". Proceedings of the Aristotelian Society 72: 229-261. “The usual charge against Carnap’s internal/external distinction is one of ‘guilt by association with analytic/synthetic’. But it can be freed of this association...”
- M Allspector-Kelly (2001). "On Quine on Carnap on Ontology". Philosophical Studies 102: 93-122. “Quine’s and Carnap’s views are much closer than Quine ever suspected.”
- Graham H. Bird (1995). "Carnap and Quine: Internal and external questions.". Erkenntnis 42 (1): 41-64. Reprinted in: Graham H. Bird (2003). “Carnap's internal and external questions”, Thomas Bonk, ed: Language, Truth and Knowledge: Contributions to the Philosophy of Rudolf Carnap. Springer. ISBN 1402012063. "I want to argue that Quine's criticisms leave Carnap's central points quite untouched."
- Jonathan Schaffer (2008). “Chapter 12: On what grounds what”, D. Chalmers, D. Manley, & R. Wasserman, eds: Metametaphysics: New Essays on the Foundations of Ontology. Oxford University Press. ISBN 0199546045.
- Frank X Ryan (2004). “Analytic: Analytic/Synthetic”, John Lachs, Robert B. Talisse, eds: American Philosophy: An Encyclopedia. Psychology Press, 36-39. ISBN 020349279X.
- Graham H. Bird (1995). "Carnap and Quine: Internal and external questions.". Erkenntnis 42 (1): 41-64. Reprinted in: Graham H. Bird (2003). “Carnap's internal and external questions”, Thomas Bonk, ed: Language, Truth and Knowledge: Contributions to the Philosophy of Rudolf Carnap. Springer. ISBN 1402012063. "He [Carnap] might not definitely deny the application of the analytic/synthetic distinction, but even choose to be agnostic about it."
- See Metaphysics After Carnap: the Ghost Who Walks?, p. 10.
- Schaffer, Jonathan (March 19, 2007). Edward N. Zalta, ed:Monism. The Stanford Encyclopedia of Philosophy (Fall 2008 Edition).
- Peter van Inwagen (2008). “Chapter 6: Quine's 1946 lecture on nominalism”, Dean Zimmerman, ed: Oxford Studies in Metaphysics : Volume 4. Oxford University Press, pp. 125-144. ISBN 9780199542987.
- Ludwig Wittgenstein (2001). Philosophical Investigations. Blackwell Publishers. ISBN 0631231595. Quoted in Morton White (1957). The Age of Analysis. George Braziller, pp. 231-232. For a discussion see Daniel Hutto, particularly p. 143.
- Huw Price (2009). “Chapter 11: Metaphysics After Carnap: the Ghost Who Walks?”, David Chalmers, Ryan Wasserman and David Manley, eds: Metametaphysics: New Essays on the Foundations of Ontology. Oxford University Press, 320-346. ISBN 0199546045.
- Amie L Thomasson (to be published). “Carnap and the prospects for easy ontology”, Ontology after Carnap. Oxford University Press.
- Amie Thomasson (2012). “Chapter 1: Research Problems and Methods in Metaphysics”, Robert Barnard & Neil Manson, eds: The Continuum companion to metaphysics. Continuum International Publishing Group, 14-45. ISBN 978-1-4411-3022-8.
- Rudolf Carnap (1963). Paul Arthur Schlipp: The Philosophy of Rudolf Carnap. Open Court, p. 869.