Simple (philosophy)

In contemporary mereology, a simple or indivisible monomere (in mereology, not in chemistry) is any thing that has no proper parts. Sometimes the term "atom" is used, although in recent years the term "simple" has become the standard.

Simples are to be contrasted with atomless gunk (where something is "gunky" if it is such that every proper part has a further proper part; a potential omnidivisible). Necessarily, given the definitions, everything is either composed of simples, gunk or a mixture of the two. Classical mereology is consistent with both the existence of gunk and either finite or infinite simples (see Hodges and Lewis 1968).