. This involves a preliminary comparison of the space of
with the space of
. Such a comparison can only be made by reference to events which are facts common to all observers, thus showing the fundamental character of events in the formation of space and time. The ideally simple event is one indefinitely restricted both in spatial and in temporal extension, namely the instantaneous point. We will use the term 'event-particle' in the sense of 'instantaneous point-event.' The exact meaning of the ideal restriction in extension of an event-particle will be investigated in [Part III]; here we will assume that the concept has a determinate signification.
8.2 An event-particle occupies instantaneously a certain point in the space of
and a certain point in the space of