Physical Constants Indicate Fine-Tuning for Life

This article reviews evidence that physical laws, constants, and early-universe conditions are finely tuned to permit life, citing examples such as gravity, the strong and weak forces, quark masses, and the cosmological constant. It also discusses constraints on early parameters like the critical density, density fluctuation amplitude Q (~2×10^-5), and exceedingly low initial entropy. The constraints imply small parameter changes would prevent stars and heavy-element formation.