Full Idea
The parts of a lamp stay together when it is moved (which is one of Aristotle's criteria for objecthood).
Gist of Idea
Aristotle says an object (e.g. a lamp) has identity if its parts stay together when it is moved
Source
Hilary Putnam (Representation and Reality [1988], §7 p.110)
Book Reference
Putnam,Hilary: 'Representation and Reality' [MIT 1992], p.110
A Reaction
Metaphysics 1052a26 (just after the cross-reference) says a thing may be unified 'if its movement is single'.
Related Idea
Idea 16508 Things are more unified if the unity comes from their own nature, not from external force [Aristotle]