Argle. I’ve said it before and I’ll say it again: all things are material. Either holes are somehow material, or else there are no such things. Maybe a hole is the material hole-lining that, as we so misleadingly say, “surrounds” the hole; or else whatever ostensible reference we make to holes is secretly some other sort of language-game altogether, or it’s fictitious reference, or it’s just plain mistaken.