Institute for Advanced Study / Princeton University Joint Astrophysics Colloquium

The search for life in the Universe is frustrated by a single known example, ourselves - a data point loaded with selection bias. In such a data starved regime, priors have an outsized role and it's tempting to throw our arms in the air in despair. But objective Bayesianism and anthropic reasoning have made successful predictions in cosmology and here I discuss their implications for life. I'll discuss why M-dwarfs are improbable seats for observers such as ourselves, how Earth's chronology indicates that abiogenesis is a rapid process, and objective Bayesianism introduces a fine-tuning problem for SETI optimists. I'll next discuss epistemic problems facing the search for the life, such as the outrageous flexibility of the alien hypothesis undermining scientific norms. Finally, I'll discuss new, unpublished work on how planned surveys for biosignatures, such as HWO, have a catastrophic flaw and how a major strategy redesign might be able to salvage such surveys.