当代科学实在论最重要的辩护模式是“非奇迹论证”(No Miracles Argument,简称NMA),但劳丹等人利用著名的“悲观归纳”(the Pessimistic Induction,简称PMI),强有力地揭示了NMA的理论困境——它与科学发展的实际历史不符。时至今日,科学实在论的一个重要任务还是要回答“悲观 The most important mode of defense in contemporary scientific realism is ”No Miracles Argument“ (NMA), but Laudan et al use the famous ”Pessimistic Induction“ (PMI) It has revealed the theoretical predicament of NMA strongly - it does not accord with the actual history of scientific development. Today, an important task of scientific realism is to answer ”pessimism."