The paper presents Jonathan Swift's Gulliver's Travels as the first attempt to claim that thought experiments, namely the close analysis of contrived counterfactual scenarios, are the only way we challenge normative framework assumptions and learn anything significantly new in and outside science. The standard epistemologies of his day – Baconian empiricism and Cartesian rationalism –fiercely ridiculed in the course of Gulliver's third voyage, are cruelly dismissed as powerless to advance knowledge, and keep it in normative check. The transformative effect of the clever thought experiments presented in the three other voyages (of imagining London shrunk to a twelfth of its size and enlarged to giant proportions, and a more responsible and intelligent race of beings inserted above (normally sized) humans) enable Swift to obtain critical normative distance from several major assumptions about politics, religion, aesthetics, ethics, and much more, including the limits of the thought experiment itself. In the second part of the paper, the impressivre use to which the Talmudic literature puts such imagined counterfactual scenarios, is examined, with special reference to ethics and law.