Part/Whole : Clippings on Mereology

"(1)	The handle is part of the mug.
(2)	This cap is part of my pen.
(3)	The left half is your part of the cake.
(4)	The cutlery is part of the tableware.
(5)	The contents of this bag is only part of what I bought.
(6)	That area is part of the living room.
(7)	The outermost points are part of the perimeter.
(8)	The first act was the best part of the play."

"(12)	The conclusion is part of the argument.
(13)	The domain of quantification is part of the model.
(14)	The suffix is part of the official file name.
(15)	Rationality is part of personhood."

"regardless of how one feels about matters of ontology, if ‘part’ stands for the general relation exemplified by (1)-(8) and (12)-(15) above, then it stands for a partial ordering—a reflexive, transitive, antisymmetric relation:

(16)	Everything is part of itself.
(17)	Any part of any part of a thing is itself part of that thing.
(18)	Two distinct things cannot be part of each other."

"As it turns out, virtually every theory put forward in the literature accepts (16)–(18), though it is worth mentioning some misgivings that may, and occasionally have been, raised."

- Stanford Encyclopedia of Philosophy