The two prominent, competing material models of mereological essentialism are endurantism and perdurantism.
It is important to note that neither endurantism nor perdurantism imply mereological essentialism.
Within an endurantist framework, objects are extended within space; they are collections of spatial parts.
Objects persist through change (endure) by being wholly present at every instant of time.
Within a perdurantist framework, objects are extended through space-time; they have parts in both space and time.
Additionally, X ceases to exist if it gains a new part, c. Mereological essentialism is a position defended[by whom?]
For instance, several answers have been proposed regarding the question: "What is the relationship between a statue and the lump of clay from which it is made?"
Coincidentalism is the view that the statue and the lump of clay are two objects located at the same place.
Michael Jubien and Mark Heller defend mereological essentialism for perduring objects.
Some are more formal; others use mereological essentialism as a solution to various philosophical puzzles or paradoxes.
But mereological inessentialism means that a table would survive replacement or loss of any of its parts.
Because it is difficult to justify a clearly defined point at which the table is destroyed and replaced by the chair, the best solution to this puzzle may be mereological essentialism (Chisholm 1973).
Defending this view is rejecting the principle of arbitrary undetached parts (Van Inwagen 1981).