Mereology
From the Quicksilver Metaweb.
Mereology is the study of parts and wholes, and the relations thereof. Is, for example, a bicycle an object in its own right? Or would it be more correct to say that it is a collection of other, smaller, complicatedly connected objects? Set Theory is closely connected with this study, and Russell's Paradox (Is a set of all sets not members of themselves a member of itself?) is an example of the intellectual problems an unsound or inappropriate mereology can produce.