Thought Experiments in Plato

In the history of thought experiments, Plato plays a major part not only because we find in his writings one of the earliest documented uses of thought experiments ¹ but also because one of the most influential thought experiments ever concocted is due to him. For the systematic study of thought experiments he is interesting also in two other respects. Usually, a thought experiment is a piece of fictional writing, but not every piece of fiction is a thought experiment. Plato’s writings are full of different kinds of fiction so that the question poses itself what distinguishes thought experiments from those other kinds of fiction he employs. Further, every thought experiment is an invitation by the author to imagine something, usually addressed to the reader. Plato’s texts are dialogues where one interlocutor proposes something to another interlocutor. This is true, of course, also for thought experiments which appear in the dialogues. Therefore, Plato not only presents thought experiments but he presents their audience and the reaction of the audience as well. This does not imply, of course, that the reader is not addressed. But she is addressed in more than one way – directly, as far as she might put herself in the place of a dialogue interlocutor; indirectly, as far as she is witness to the presentation and reception of a thought experiment like the spectator of a drama who is able to observe both sides and to take a look at the use of thought experiments from the outside.