Sure, if it&#x27;s not actually reactionless, most objections fall away.<p>The problem with reaching for exotic particles or the like is that we don&#x27;t see them in searches which involve tens of orders of magnitude more power, and we certainly don&#x27;t see them in, for example, electric toasters or radar sets.    So what would need explaining is what&#x27;s peculiar about the EmDrive with respect to (extremely) unusual particle interactions, and there is [a] nothing obvious and [b] nothing at all in the &quot;theory&quot; paper.<p>Likewise, reaching for non-local physics answers raises similar questions (why is EmDrive doing non-local whatever but my kettle isn&#x27;t; or alternatively, why is EmDrive coupling with whatever much much much more strongly than my conventional oven is).<p>I have another pair of things that you can add to the list: [a] EmDrive somehow violates causality in a way that other similar arrangements of mass-energy-momentum does not and [b] EmDrive somehow escapes logic in a way that other similar systems under study does not.   These are neither more far-fetched nor more unpalatable, compared to abandoning local physics (causality and logic preserved, but hidden non local variables proliferate) or abandoning the Standard Model as an accurate low-energy theory of matter (causality, logic and locality preserved, but now what happens in the molecules and atoms of cars, computer chips, and light bulbs?  we no longer can be quite so sure!).<p>There is A LOT of known physics and almost exactly zero examples of violations of the known invariants at low particle energies.  You are re-testing relevant parts of all that in reading this comment.