"Upstairs" II and Conceptual Issues.
Two possible accounts of a lifetime and an awareness in Alan Moore's Jerusalem:
Assuming Four Spatial Dimensions And One Extra Temporal Dimension
A lifetime extends in four dimensions.
It extends along the fourth dimension as a tunnel.
An awareness is a three dimensional ball of light.
It moves along the tunnel.
Having left the tunnel and looked back, it should see the tunnel but not itself in the tunnel, any more than we see ourselves still walking along the road when we glance back.
Assuming Only Four Spatial Dimensions And No Extra Temporal Dimension
First two propositions as above.
An awareness is a four dimensional tube of light extending along the tunnel.
The awareness views not the entire tunnel but only each three dimensional cross-section.
Having left the tunnel and looked back, it will see itself still in the tunnel.