I tend to think that a physical system of numbering and an entirely nonphysical system of belief as apples and oranges- entirely incomparable. Specifically, adding or subtracting earplugs is an entanglement of reality and belief whereas choosing eg. christianity or islam is simply something of belief- yes, that spiritual belief is affected by your reality (environmental factors like schooling, parents and location, obviously) but in the end, it is still a belief- for example, if a person never heard of Jesus or Muhammad but nonetheless believed in a higher power or similiar disposition, does this make them muslim, christian, neither or both? Furthermore, if somebody really wants to believe that sound travels in space, then their belief may well prevail despite all evidence against it as the person creates 'exceptions' to their beliefs that they believe do not disprove their theory. Hope this made sense...