German term meaning "thought experiment." Occassionally shows up in English, especially in discussions of theoretical physics. A Gedankenexperiment need not actually be carried out, and in some cases can't be carried out. The idea is simply to imagine the effects of a known principle on a reasonably simple real-world setup. Perhaps the most famous gedankenexperiment is Schrodinger's cat. Other examples include Einstein's efforts to imagine what he'd see sitting on an object that approached the speed of light, or the question "what would happen if I put a toothpick covered by a large fishbowl, slightly raised so as to allow air circulation, in the microwave?"