An Introduction to Ontology
One of the most influential papers in ontology is W. V. O. Quine’s “On What There Is?”, published in the Review of Metaphysics 1948/49. The paper has a critical and a constructive part. Quine criticizes a Platonist ontology for being far too rich: it contains entities that he finds it hard to accept as real, notably universals (properties like “being yellow”; relations like “being north of” and kinds like “being human”) and nonexistent objects like Pegasus, the winged horse of Greek mythology. This critical approach reflects Quine’s predeliction for “desert landscape ontologies” that he confessed to elsewhere. In the constructive part Quine develops a method to decide which entities we should believe exist—that is he develops a method for finding one’s “ontological commitments”. The method is to consider all the things you believe to be true, and then see what statements of ontological commitments follow, by the rules of logic, from these beliefs. Quine urges that many statements that seem to commit us to the existence of, say, Xs, don’t really do so, as those statements can be “paraphrased” into statements that have the same content but do not commit us to the existence of Xs. For example: the statement that there is a hole in the donut, seems to commit us to the existence of holes, which is puzzling, as holes are nothings. The statement, however, can be paraphrased in a way that has no such commitment: The donut is perforated.