- Example:
- Volume Weighting: Prefers bubbles with fast expansion (large ).
- Anthropic Selection: Only bubbles with small are relevant.
- Partial Solution: Bayesian measurement approach with entropic constraints (Bousso, 2011).
5.2.2 Reliance on Unconfirmed String Theory Parameters
- Unconstrained Parameters:
- The flux charge \( q_i \), number \( n_i \), and potential moduli \( V(\phi) \) depend on details of the unobserved Calabi--Yau compactification.
- Example: The value \( f \) (axion decay constant) must be set \( \sim 0.1 M_{\text{Pl}} \) to produce \( r \sim 0.003 \), but this does not come from first principles.
- Criticism from Community:
- The model is accused of "moving fine-tuning from to string theory parameters" (Cicoli et al., 2019).
5.3 Next Steps