Skip to content
CosmosExplorer
Chapter 01 · Before the Universe/Mathematical & Structural

Eternalism / Block Universe

1966 / 1967 · C. W. Rietdijk, Hilary Putnam, Albert Einstein (origin)
Speculative

All moments, past, present, future, coexist equally in a 4D spacetime block.

Skip 3D content

In one sentence

Eternalism holds that all moments in time exist equally. The universe is a static 4D block, and our experience of time passing is an illusion.

The claim

Eternalism is the metaphysical position that all events, past, present, and future, exist with equal ontological status, embedded in a four-dimensional spacetime "block." Einstein himself held this view, famously writing after a friend's death: "for us believing physicists the distinction between past, present, and future is only a stubbornly persistent illusion."

Rietdijk (1966) and Putnam (1967) developed independent arguments that special relativity logically implies eternalism: since observers in different reference frames cannot agree on what is "now," there can be no objective present, and all moments must be equally real.

This is technically a metaphysical position rather than a cosmological theory, but it has direct implications for "before the universe", in eternalism, the question is malformed. There is no temporal before in any privileged sense; the entire 4D block simply is.

The family stance

Either all mathematical structures (Tegmark Level IV), or a timeless 4D block where past/present/future coexist (Eternalism). In both cases, the notion of a temporal "before our universe" is rejected.

Predictions

  • Time is a dimension, not a flow
  • There is no objective "now" or arrow of time at the fundamental level
  • Free will is constrained or illusory

Evidence

  • Compatible with special and general relativity
  • Endorsed by Einstein, Gödel, Putnam, and many physicists/philosophers

Counterpoints

  • Conflicts with subjective experience of time
  • Free will and moral responsibility become problematic
  • Argument from relativity is itself contested (Stein 1968)
0votes
Go deeperTechnical detail with proper terminology

The Rietdijk-Putnam argument runs roughly: observer A sees event X as simultaneous with their "now." Observer B, in a different frame moving relative to A, sees event Y as simultaneous with their own "now," but Y is in A's future. By transitivity of simultaneity-with-the-real, Y must be real now for A. Therefore all events in the spacetime are equally real.

This argument has been criticized (Stein 1968, Saunders 2002) on the grounds that "real for X" is not transitive in special relativity. The debate persists.

In general relativity, there is no global notion of simultaneity, which arguably strengthens the case for eternalism, but the position remains philosophically contested.

References

  1. Established
    Rietdijk (1966). Philos. Sci. 33, 341
  2. Established
    Putnam (1967). J. Philos. 64, 240
  3. Debated
    Stein (1968). J. Philos. 65, 5, critique

Spotted an error? Have a source to add?

Prefer email?

You can also send a prefilled email with the variant URL already filled in.

Related theories