block-world--past, present, and future events all exist, like the parts of a spatially extended block
presentism--only things that exist in the present exist, and there is some notion of temporal becoming
Mark walks from a room described by a block-world into a room where presentism holds true. What, if anything, happens? 'When' does it happen?
There are 3 cases:
case 1: time, outside of both rooms, is presentist
case 2: time, outside of both rooms, is block-world
case 3: neither case 1 nor case 2