Chapter 4 Possibility and probability: Value, conflict and choice

Consider now the set of all possible events that can occur in a given context. There is a distinction between an elementary event and a compound event. The set of elementary events is exhaustive, exclusive and elementary: the elementary events cover all the possible events; no two of them can occur at the same time; and all other events are constituted by compounds of these. Denoting the set of all elementary events by E , the set of all (possibly compound) events is the power set of E , S E . The set of events, S E , consists of pairs of events: for each event e there is its complementary event not- e ; and for the event not- e there is its complementary event not-(not- e )= e . In any given world only one event of any complementary pair can occur.