At the Concerned Philosophers for Peace Annual Conference, PACS Institute Director Anders Reagan presented When Peace Fails: Typologies Under Scientific Scrutiny, tackling peace studies’ core problem: there’s still no shared definition of “peace.” He presented a paper aiming to test leading definitions against Fiona Hibberd’s criteria for scientific definition—showing that many blur what peace is with what it does. Reagan also advanced a structural, sentience-based definition: peace exists exactly when interacting sentient beings experience aligned fitness payoffs within a stated domain and interval. This reframing aims to replace conceptual fragmentation with a coherent, testable ontology that enables cumulative research and more harmonized practice. Next steps include a systematic comparative analysis, possible publication in the forthcoming Philosophy of Peace volume, and development of a practicable scientific model of peace for scholars and practitioners alike.