“… 6 The same goes for extant fallibilist solutions to the threshold challenge. Consider, for instance, Immerman (2020)’s cluster account, on which there is a large cluster of properties such that none are individually necessary or sufficient for turning one’s belief into knowledge (lack of one property can be made up for by having another), but if one’s belief instantiates sufficiently many of them, one knows that . Importantly, if just one of the properties in the cluster is gradable, my challenge arises for the cluster view.…”