Full Idea
Given a prior commitment to cats, a commitment to cat-fusions is not a further commitment. The fusion is nothing over and above the cats that compose it. It just is them. They just are it. Together or separately, the cats are the same portion of Reality.
Gist of Idea
Given cats, a fusion of cats adds nothing further to reality
Source
David Lewis (Parts of Classes [1991], 3.6)
Book Reference
Lewis,David: 'Parts of Classes' [Blackwell 1991], p.81
A Reaction
The two extremes of ontology are that there are no objects, or that every combination is an object. Until reading this I thought Lewis was in the second camp, but this sounds like object-nihilism, as in Van Inwagen and Merricks.
Related Ideas
Idea 15522 The one has different truths from the many; it is one rather than many, one rather than six [Lewis]
Idea 17861 Two men do not make one thing, as well as themselves [Aristotle]