The variables of quantification, 'something,' 'nothing,' 'everything,' range over our whole ontology, whatever it may be; and we are convicted of a particular ontological presupposition if, and only if, the alleged presuppositum has to be reckoned among the entities over which our variables range in order to render one of our affirmations true.
Willard Van Orman Quine, Roger F. Gibson (2004). “Quintessence: Basic Readings from the Philosophy of W.V. Quine”, p.187, Harvard University Press