four-dimensional block
Compiled with AI assistance and selectively reviewed. Please consult the cited passages; the books remain the authoritative source. About this companion
Editorial synthesis · provisional
Definition
The four-dimensional block is the eternalist picture of spacetime as a fixed totality in which past, present and future equally exist and temporal passage is perspectival rather than genuine becoming. The books present it as an opponent of an unfinished reality, while distinguishing relativistic description and the absence of a universal now from proof that all events already exist.
Explanation
AB describes the block's appeal through relativity and the spacetime diagram, then objects that a completed representation need not establish a completed world. Its critique retains relativity's denial of a cosmic now and expressly declines to prove that becoming runs all the way down. The narrative note separately addresses symmetric equations, observer-dependent simultaneity and fears of signals from the future.
PB opposes the frozen all-at-once to an eternal present understood as continuing presencing, not an enduring instant. RB1 attributes the rejection to Kastner's transactional account and cites Unger and Smolin against inferring timeless ontology from time-symmetric descriptions. Its native note calls the block eternalism and contrasts it with real indeterminacy resolved in particular transactions. RB2 independently develops the criticism: mathematical description does not establish completion, and rejecting a universal present need not deny real, heterogeneous time. Its actual is a growing record, not a completed block.
Scope and attribution
AB, PB, RB1 and RB2 own direct critical treatments. These descriptions preserve the manuscripts' interpretation and objections rather than purporting to settle debates about relativity or eternalism. RB3 ordinary building-block and blocking language does not supply a block-universe treatment.
AB — The Actual Book
AB argues against turning the spacetime map into a completed ontology, while conceding that relativity supplies no cosmic now and that the argument does not prove fundamental becoming.
Occurrence locators: 38, 39, 40; Thinker register: 228; Notes: 238.
PB — The Possible Book
PB contrasts the block's frozen all-at-once with the making of events at an eternal present; its commentary insists that what persists is presencing, not a moment.
Occurrence locators: 92, 167.
RB1 — The Real Book, Volume I: The Possible Is Real
RB1 defines the block as eternalism in a native note, attributes its rejection to Kastner, and invokes Unger and Smolin against treating temporal symmetry as proof of timelessness.
Occurrence locators: 66, 70, 99, 139, 159; Notes: 66.
RB2 — The Real Book, Volume II: Becoming Is Being
RB2 opposes completed totality to unfinished reality and argues that observer-dependent simultaneity denies a universal present, not necessarily becoming. Its growing actual record is explicitly not a completed block.
Occurrence locators: 210, 232, 265.
Background used in the editorial explanation
Domain-specific mechanisms and wider analogies remain distinguished. Original definitions retain their scope; local cross-references do not rewrite them. Named theories and mechanisms are distinguished from neighboring background, homonyms and the author’s own synthesis. Reproduced AI passages retain their separate voice.