Page "Ontological commitment" Paragraph 3

For example, the sentence involving Napoleon can be rewritten as “ any group of people that includes me and the parents of each person in the group must also include Napoleon ,” which is easily interpreted as a statement in second-order logic ( one would naturally start by assigning a name, such as G, to the group of people under consideration ).

Formally, collective noun forms such as “ a group of people ” are represented by second-order variables, or by first-order variables standing for sets ( which are well-defined objects in mathematics and logic ).

Since these variables do not stand for individual objects, it seems we are “ ontologically committed ” to entities other than individuals — sets, classes, and so on.

As Quine puts it,