Full Idea
Mereological essentialism says that an object's parts are necessary for its existence. ....It is literally never correct to say that an thing survives a change in its parts.
Gist of Idea
Mereological essentialism says an object's parts are necessary for its existence
Source
Theodore Sider (Four Dimensionalism [2001], 5.7)
Book Reference
Sider,Theodore: 'Four Dimensionalism' [OUP 2003], p.181
A Reaction
Chisholm is well known for proposing this view. Sider adds a possible toughening clause, that the parts are also sufficient for the object's existence. This is a philosophers' notion of identity, not the normal English language concept.