Transient Observers and Variable Constants, or Repelling the Invasion of the Boltzmann's Brains

Abstract

If the universe expands exponentially without end, ``ordinary observers'' like ourselves may be vastly outnumbered by ``Boltzmann's brains,'' transient observers who briefly flicker into existence as a result of quantum or thermal fluctuations. One might then wonder why we are so atypical. I show that tiny changes in physics--for instance, extremely slow variations of fundamental constants--can drastically change this result, and argue that one should be wary of conclusions that rely on exact knowledge of the laws of physics in the very distant future.

4 pages, LaTeX; v2: added references; v3: more discussion of setting, alternative approaches, now 5 pages; v4: added discussion of the effect of quantum fluctuations on varying constants, appendix added, now 7 pages; v5: new reference, minor correction

References in corpus (6)

• Sinks in the Landscape, Boltzmann Brains, and the Cosmological Constant Problem
• A Universe Without Weak Interactions
• Limit on the Temporal Variation of the Fine-Structure Constant Using Atomic Dysprosium
• Freak observers and the measure of the multiverse
• Susskind's Challenge to the Hartle-Hawking No-Boundary Proposal and Possible Resolutions
• Composition-dependent long range forces from varying m_p/m_e

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• Agnesi Weighting for the Measure Problem of Cosmology
• No-Bang Quantum State of the Cosmos
• Spacetime Average Density (SAD) Cosmological Measures
• Gravity can significantly modify classical and quantum Poincare recurrence theorems
• Disentangling the Cosmic/Comoving Duality: The Cognitive Stability and Typicality Tests