Martin Rees

Background

Sir Martin Rees (b. 1942) is a British cosmologist and astrophysicist, Astronomer Royal, and author of Just Six Numbers (2000), the best-known popular exposition of anthropic multiverse cosmology. Rees frames the apparent fine-tuning of the physical constants not as evidence of design but as an artifact of observer selection within a vast ensemble of universes: if the constants vary across a multiverse, then a life-permitting universe somewhere is unsurprising, and, necessarily, that is where observers find themselves.

Rees is not in this public-domain corpus; his position is presented through the Stanford Encyclopedia's careful summary of the multiverse literature. He is treated in this wiki as the representative popular voice of the multiverse response to the fine-tuning argument.

Positions held in this wiki

• The Fine-Tuning Argument — grants that our universe is "life-friendly to an astonishingly precise degree" but denies this raises the probability of design, because observer-selection over an ensemble absorbs the surprise (SEP 'Fine-Tuning' §4). The article flags that "our corpus does not contain Rees, Carr, Tegmark, or Susskind directly."
• Origin of the Universe — the inflationary-ensemble reading in which our universe is one member of a larger cosmological population.

Key works in our corpus

Corpus gap: Just Six Numbers (2000) is not ingested. The multiverse response it popularizes is represented via SEP 'Fine-Tuning' §4. See meta/ingestion-queue.md.

Principal critics

• Robin Collins — the leading contemporary defender of the fine-tuning design inference, who argues the multiverse merely relocates the need for explanation (the generating mechanism must itself be fine-tuned).
• William Lane Craig — presses that a multiverse posited ad hoc to defuse fine-tuning faces both the Boltzmann-brain problem and the charge of being unobservable.

See also

• Bernard Carr — anthropic cosmologist and frequent co-author.
• Alan Guth — inflationary theory, the physical basis often invoked for multiverse generation.