  Let us first say something very general about how such a case might proceed. Some propositions have a certain degree of intrinsic plausibility. For example, the statement that there is no paradoxical decomposition of the sphere using pieces that are Σ̰12 is intrinsically plausible, although it is not provable in ZFC. Such initial support for a proposition is not definitive. For example, the statement that there are no space filling curves and the statement that there is no paradoxical decomposition of the sphere using any pieces whatsoever might have once seemed intrinsically plausible. But in each case these statements were overturned by theorems proved against the backdrop of systems that had much more than this degree of initial plausibility in their favour. However, although such intrinsic plausibility is not definitive, it nevertheless has some weight. 