Specialization is a Driver of Natural Ontology

Part of what makes a pencil a good object is that all its parts share approximately the same rotational velocity - i.e. it's a rigid body object. Part of what makes a squirrel a good object is that its parts share approximately the same genome. Part of what makes the water in a cup a good object is that its parts share approximately the same chemical composition - i.e. it mixes quickly. General pattern: part of what makes many objects good objects (i.e. ontologically natural ) is that their parts all share approximately the same, given time to equilibrate.