Philosophers no longer argue whether Hume ever read Berkeley, yet some remain puzzled as to why so little of Berkeley appears in Hume's works. Professor Popkin has remarked that even “where Hume and Berkeley come closest to discussing the same subject or holding the same view, Hume neither uses Berkeley's terms nor refers to him.” An apparent exception to this generalization is Berkeley's doctrine ofminima sensibilia, for both philosophers use this term to denote indivisible sensible points, and both invoke such points in order to show that sensible extension is not infinitely divisible. Yet it has been suggested that, although Berkeley and Hume employ the same terms, they nevertheless maintain different doctrines: Hume'sminimaare unextended, whereas Berkeley's are extended.