Perhaps persons are somehow simple entities. It might appear that they could be simple bodily substances — perhaps like extra-small versions of the Luz Bone mentioned by Leibniz (in Book II, Chapter xxvii of the New Essays). But Chisholm had defined ‘bodily substance’ as ‘substance with parts’. Thus on his view, there cannot be a simple bodily substances. So if the person is a simple substance, it must be simple and immaterial — a “monad” as Chisholm says.[1]