Metaphors
Five images that carry the argument
§ 2.375
The Rectangular Prism
A cross-section of a prism is a square. The square is real; it possesses every property of that location. Nevertheless the square is not the prism. The prism is the complete structure: the ordered collection of all its cross-sections.
Now let two prisms share an identical sequence of cross-sections and diverge only later. Drag the slice back through the shared region. Every square there is identical — and yet there was never one prism that became two. There were always two structures overlapping for part of their extent.
An instantaneous conscious state is a cross-section. It is not the person.
§ 2.25
The Red Star and the Blue Star
Two individuals share every experience, memory, thought and physical state up to a moment. Then one observes a red star and the other a blue star. It is tempting to say that one person became two.
Under the block universe both futures are already real. The red-star future belongs to one complete structure; the blue-star future to another. The structures differ, so the persons differ — from the outset. No later event creates the distinction; the distinction is already in the structure.
Two roads may share a route before separating, yet they are not the same road.
§ 6 — 6.5
Recurrence, Not Copying
Recurrence is not one life ending, vast time passing, and an identical life appearing later. If the universe recurs, spacetime itself recurs. The recurrence is not something that happens inside time; it is a recurrence of the structure that contains time.
Nor is it a copy. A copy is something that resembles an original while remaining numerically distinct from it — a description that presupposes a person standing behind the worldline. There is no such person. The worldline exists wherever it is instantiated.
Occurrence number is a label applied from outside. It is not a property of the person.
§ 2.5 — 9
The Absent Observer
“Who is having the experiences?” The conscious worldline. “Who is experiencing the worldline?” The question assumes an experiencer standing behind the experiences. There is none. The conscious life is not possessed by a subject; the conscious life is the subject.
The same emptiness answers death. Nonexistence contains no experience. It is not a darkness that is lived through — it is simply the absence of experience, and so no interval is ever experienced between one instantiation of a worldline and another.
Experience exists where the worldline exists. Nothing more is required.
§ 3.5
The Open Book
A character at page 100 knows only what happened on the pages before it. Page 200 is real, fully written, and complete — yet the character cannot read it. The book as a whole exists; the character’s knowledge is limited to the part of the book that has been revealed to it.
We are outside observers of the book. We can see page 1 and page 200 at once, because the entire structure lies open before us. But there is no such outside observer for us. No reader stands above the worldline. The worldline itself is the subject of the experiences it contains.
The block universe is the book; the self is not a page, but the whole written line.
We can see every page at once. The character cannot.