 The primary operation in Royce’s logic is the exclusive  disjunction[6],  an operation or possible operation that divides actions into two “obverse” or incompatible categories where if one action from a category is taken, it eliminates the possibility of taking an action in the other. For example, an exclusive disjunction is present when an agent selects a candidate on a ballot. To select the candidate is to lose the option to choose another or to simply opt out of voting. Put another way, actions are exclusively related when they are incompatible, that is, they cannot be taken together. Royce’s logic is founded on the relation that expresses the operation of judgment, that is, the selection by an agent of one alternative over another where the alternatives are incompatible. System \(\Sigma\) is a logic of modes of action and a logic of agency.