 There have been several attempts to define “thought experiment” along the lines of traditional conceptual analysis (see, e.g., Picha 2011; McComb 2013), but likely it will be better to leave the term loosely characterized, so as not to prejudice the ongoing investigation. Of course, we need to have some idea as to what thought experiments are to guide a proper philosophical analysis (see Häggqvist 2009), but this does not mean that we need to begin with a technical definition, specifying necessary and sufficient conditions. In fact, many of the most important concepts we deal with remain rather loosely defined when philosophical inquiry begins, e.g., religion or democracy. Luckily, there are plenty of examples to refer to in order to circumscribe our subject matter well enough. As well as those already mentioned, there are Newton’s bucket, Heisenberg’s gamma-ray microscope, Einstein’s elevator, Leibniz’s mill, Parfit’s people who split like amoebas, and Thomson’s violinist. Everyone is probably familiar with some of these. Less familiar thought experiments include the mouse that breaks into the tabernacle of a medieval Roman Catholic Church building to feed on the consecrated wafers kept in there (see Fehige 2011). Roman Catholic Christians believe that a consecrated wafer is the body of Christ. The “substance” of the wafer, understood in terms of Aristotelian categories, is believed to be replaced. In its place is the “substance” of Christ’s body after consecration by a priest. Only the Aristotelian “accidents” of the wafer remain intact (smell, colour, texture, etc.). Does the mouse eat the body of Christ (if any human actually does)? Another example less known example is “the dome” thought experiment, which is to prove indeterminism in Newtonian physics. Imagine a mass sitting on a radially symmetric surface in a gravitational field. Guided by Newton’s laws of motion one comes to realize that the mass can either remain at rest for all times, or spontaneously move in an arbitrary direction (see Norton 2008). This thought experiment triggers a number of very interesting questions concerning the nature of Newtonian theory, the meaning of “physical”, and the role of idealizations in physics. And, of course, does it show what it claims? (see Malament 2008).