In semantics employing possible worlds, the identification of a single object that appears in the domains of several distinct possible worlds. Typical instances of such identities are found in statements such as:

• • John F. Kennedy could have been a journalist, but chose another line of work.

A standard translation of this sentence into the context of possible worlds is that although Kennedy in the actual world did not pursue journalism, there exists a possible world (call it $w$) in which Kennedy became a journalist. Identifying Kennedy in actuality with Kennedy in $w^{\prime }$ literally posits the existence of the individual Kennedy in both worlds $w$ and $w^{\prime }$. Formally, in semantics for modal logics with variable domains, the notion of transworld identity corresponds to the overlap of two distinct domains, i.e., the existence of two possible worlds $w$ and $w^{\prime }$ such that $D_w\cap D_{w^{\prime }}\ne \varnothing$.