In several places (e.g., 1991, 168), Chisholm hinted at a modal argument against materialism. He noted that he himself could survive the loss of his hand. Thus, he has this modal property: being such that it is possible for him to exist without the hand that he actually has. But Chisholm contended that his body was identical with the particular collection of human bodily parts that then constituted his body. That collection of parts could not survive the loss of Chisholm’s hand. If Chisholm’s hand were annihilated, that collection would cease to exist. Thus the collection of parts does not have the property of being such that it is possible for it to exist without the hand that Chisholm actually had. One application of Leibniz’s Law implies that Chisholm is not the collection of parts that then constituted his body. The argument clearly presupposes the doctrine of mereological essentialism, according to which if a compound thing W has a certain part P, then W cannot exist without having P as a part.