 A strategy for the sender (what Lewis called a “communicator’s contingency plan”) consists of a function specifying what signal he sends given the state of the world. It is, as Lewis notes, a function from the set of states of the world into the set of signals. This means that it is possible that a sender may send the same signal in two different states of the world. Such a strategy makes no sense, from a rational point of view, because the receiver would not get enough information to be able to identify the correct response for the state of the world. However, we do not exclude these strategies from consideration because they are logically possible strategies.