.
It follows from (i) and (iv) that
and
are inconsistent. Properties (ii) and (v) and (vi) together postulate something like the existence of an ether; but it is not necessary here to pursue the analogy.
[28. Intersection,Separation and Dissection]. 28.1 Two events 'intersect' when they have parts in common. Intersection, as thus defined, includes the case when one event extends over the other, since
is transitive. If every intersector of