AMA | October 2025

What It Covers

Sean Carroll answers Patreon supporter questions covering quantum mechanics interpretations, early universe cosmology, political violence ethics, AI epistemic effects, consciousness and physicalism, fine-tuning debates, and practical advice on scientific communication and career development in theoretical physics.

Key Questions Answered

• •Everettian Branching Mechanics: Universe branches create "thinner" worlds with amplitude squared determining thickness, conserving total probability. Each branch has half the thickness of its parent when splitting 50-50, requiring no energy expenditure. Branches exist in Hilbert space, not physical space locations.
• •Scientific Proof Standards: Science never proves anything through deduction like mathematics. Instead, researchers use Bayesian updating to adjust credences based on evidence. Credences should never reach exactly one or zero, maintaining openness to new data. Classical logic easily proves negatives by redefining propositions.
• •Universe Age Measurement: The 14 billion year age uses clocks at rest relative to cosmic microwave background radiation. Relativistic effects negligible since matter moves under 0.1% light speed. Uniform curvature across space means all co-moving observers measure identical elapsed time from Big Bang.
• •Early Universe Black Holes: Dense early universe resembles white hole, not black hole, with singularity in past rather than future. General relativity allows matter expanding from past singularity as valid time-reversed solution. No requirement for black hole formation when density high if singularity precedes expansion.
• •Political Violence Justification: Revolutionary violence justified only when broad consensus exists that no other path works and consequentialist analysis shows clear benefit. Individual assassinations rarely achieve meaningful change. Most situations require demonstrating actual effectiveness rather than emotional catharsis before considering violence legitimate.