Objet roles are temporary specializations where the object can go through, possibly more than once. An example is a person who can be a patient at times. There may be several roles like patient, employee, tax payer, etc., the phase of which may be entered and left independently, in any order.
In this paper we outline a theory which captures objects roles and phases. The theory is based on a temporal logic extended by a specific enabling predicate and a in-scope predicate. While the latter is to cope with visibility of attributes and actions as governed by creating and destroying objects as well as entering and leaving roles, the former captures nondetermism as introduced by hiding.