From the Search for Extraterrestrial Life to Interstellar Civilizations: A Stepwise Logical Analysis of Astrobiological and Technological Uncertainties

The search for extraterrestrial life has transitioned from speculative philosophy to an observationally driven scientific endeavor. However, the inference chain connecting abiotic conditions to detectable interstellar civilizations remains conceptually fragile. This paper presents a structured Bayesian analysis of the logical progression from habitability to technology. By integrating exoplanet statistics, evolutionary bottlenecks (such as the eukaryotic transition and the "oxygen bottleneck"), and civilization scaling models, we argue that each step introduces compounding uncertainties.