Abstract

The paper discusses the meta-philosophy of thought-experiments, in particular its neglected diachronic aspect, focusing on Putnam’s work as the paradigm case, and on the trail that developed out of the Twin Earth thought-experiment. Putnam's experiment is discussed from a perspective that combines metaphilosophy and actual history of analytic philosophy. Peter Unger has branded the whole debate around it as empty and fruitless. A meta- philosophical analysis shows him to be wrong. The experiment as originally proposed already appeals to a broad variation of examples and intuitive induction; the variation continues in other works addressing the issue, and produces interesting results. The second aspect is the search for reflective equilibrium, lasting till the present day. The internal logic of these processes is discussed, in order to show that the accusation for emptiness turns against Unger himself. In general, debates around thought-experiments, the already famous and also around new ones, make a large part of contemporary analytic philosophy. The way to understand a large part of this, and of debates surrounding it, is to link it to the internal understanding of a typical thought-experiment; stages of a particular experiment get discussed, developed and changed in the history of a particular trail produced by it. This is an important way in which a philosophical tradition is born, and we need to combine synchronic and diachronic approaches in order to understand it.