premise: The argument against this last approach is comparable to that which rejects stories about hoop snakes , about snakes that break themselves into many pieces and join up again , or even of ghosts that chase people out of graveyards ; the mere piling up of testimony does not prove , to the scientific mind , the <mask> of hoop snakes , joint snakes , or ghosts .
hypothesis: the proper context for <mask> here should be the state or fact of existing