 According to the eternalist, temporal location does not affect ontology. But according to a somewhat less popular version of non-presentism, temporal location does matter when it comes to ontology, because only objects that are either past or present exist. On this view, which is often called the growing block theory, the correct ontology is always increasing in size, as more and more things are added on to the leading “present” edge (temporally speaking). (Note, however, that the growing block theory does not involve any commitment to four-dimensionalism as discussed in  section 7.  In this way, the name “growing block” is somewhat misleading and the view is probably better described as the growing universe theory.) Both presentism and the growing block theory are versions of the A-theory.