With respect to time, some of the basic relations are simultaneous, before, and between. Whether this list is essentially complete, or perhaps redundant in some respects, are questions that we shall not try to answer at this point. (The answers may seem obvious to the reader now, but this impression may change as we follow the history of the problem.) At least, a theory of time must give an account of these relations and thus explicate such common assertions as (1) and (2). With respect to space, it is not easy even to make a plausible preliminary list of basic relations. It is hard to believe that such
relations as north of and east of—though they are clearly spatial relations—can be in any way basic to the subject.