Abstract

Three uses of critical thought experiments outlined in the paper are related to general questions of evaluation. A proposal offered by Karl Popper concerning the so-called "apologetic" use of Gedankenexperimente is critically assessed. Specifically, his methodological principle that one should not use a second theory in order to defend a first theory against a critical thought experiment is discussed with reference to the photon-box Gedankenexperiment and the Maxwell-demon paradox. It is argued that the rescuing of one theory from conceptual anomaly by appealing to another need not constitute a misuse of a critical thought experiment