 The examples we have seen so far involve coincidence between objects of different kinds: a cat and a tail-complement, a statue and a lump of clay. According to some versions of the standard account, constitution is always a one-way relationship: the lump constitutes the statue, but not vice versa. Accounts without this restriction can be sympathetic to coincidence between objects of the same kind. This may occur, for example, if objects of the same kind can ‘merge’ without losing their identity, or if what looks like a single object can ‘divide’ into two of the same kind (some versions of the ‘ship of Theseus’ problem have this form). The most intriguing imagined cases of fusion and fission involve people, and will be discussed briefly in  section 9.  (The claim that same-kind coincidence is impossible is sometimes called ‘Locke’s thesis’.)