Full Idea
I accept the principle of Unrestricted Composition: whenever there are some things, no matter how many or how unrelated or how disparate in character they may be, they have a mereological fusion. ...The trout-turkey is part fish and part fowl.
Gist of Idea
I say that absolutely any things can have a mereological fusion
Source
David Lewis (Mathematics is Megethology [1993], p.07)
Book Reference
-: 'Philosophia Mathematica' [-], p.7
A Reaction
This nicely ducks the question of when things form natural wholes and when they don't, but I would have thought that that might be one of the central issues of metaphysicals, so I think I'll give Lewis's principle a miss.