It is important to distinguish between the different definitions of “now” that arise when studying special relativity:
- The “observer’s” past light cone.
- The “observer’s” orthogonal slice across the block.
“Observer” is in quotes because both it and an event are idealizations. One chooses a frame of reference, then three spatial coordinates and one time coordinate. This gives a four-dimensional vector. At the tip of that cone is a 4d-coordinate.
However, an actual observer, in the common sense of the word “observer,” is composed of many brain events and hence many 4d-coordinates.
The events are not on the same hyper-surface of the present. This forces us to conclude that consciousness is not defined by an intuitive, single 2d-structure of information which maps on to the experienced now.