Full Idea
It is common in mereology to hold that there is something of which everything is part, but few hold that there is a 'null entity' that is part of everything.
Gist of Idea
There is something of which everything is part, but no null-thing which is part of everything
Source
Achille Varzi (Mereology [2003], 4.1)
Book Reference
'Stanford Online Encyclopaedia of Philosophy', ed/tr. Stanford University [plato.stanford.edu], p.14
A Reaction
This comes out as roughly the opposite of set theory, which cannot do without the null set, but is not keen on the set of everything.