Editing Roderick Chisholm (section)

==Persistence and Identity==

In his book ''Person and Object,''<ref name=":0" /> Chisholm endorses a mereological essentialism for everyday objects such as tables and chairs. He distinguishes two ways of thinking about the identity of such objects and how they may lose or gain parts over time: a "strict philosophical sense" and a "loose sense." In a strict philosophical sense, we must say that everyday vulgar objects do not persist through even the slightest change of parts. This is a strict [[Mereological essentialism|mereological essentialist]] view. If any part of an everyday or 'vulgar' object is lost or gained over time, the object would cease to exist. (See Chisholm's Stanford Encyclopedia entry for more about vulgar objects).<ref name=":1" /> The object from before is now a new and different one. Chisholm argues that these vulgar objects persist through time only in a philosophically loose sense. If we consider these objects carefully, they are better understood as merely feigning identity, what Chisholm calls "ontological parasites" or ''ens per alio.'' If we consider a table in which we change out individual parts each day for a week, we may, at the end of the week, say there has only been one table in front of us; however, this is only the loose way of talking. The single 'table' we are referring to in that sentence is really only (Chisholm borrowing a phrase from Hume) a 'succession of related objects.' The single "table" we refer to plays loose with identity. In a strict philosophical sense, if the table has had seven changes to its parts, there have been seven different tables. We may innocently discuss much of the world around us as persisting through change in the loose sense, but when we consider strict philosophical puzzles, we must not be fooled by ontological parasites.

Chisholm considers this theory with the famous philosophical puzzle of [[Ship of Theseus|The Ship of Theseus]]. According to mereological essentialism, once a single plank of the ship is removed, the ship has become a different object. We may continue to talk about the Ship of Theseus as if it persisted, but this would only be in the loose sense discussed above. Chisholm solves the puzzle by saying that, in the strict and philosophical sense, there is no persistence between the mereologically different objects. Note the possible implication for the "reconstructed ship" that is often a part of the thought experiment. If every single part of the original ship were saved perfectly, so that they were materially identical and rebuilt next to the new ship, Chisholm's mereological essentialism may lead him to agree that this is ''the'' original Ship of Theseus.

However, Chisholm's mereological essentialism does not extend to persons. Persons, unlike everyday vulgar material objects like ships and tables, persist in the strict and philosophical sense, even when they change their parts. This runs counter to his mereological essentialism in vulgar objects. He provides various arguments for why there is such a dividing line between the two and why persons are special. One argument is from the first hand experience of the unity of consciousness.<ref name=":0">{{Cite book|last=Chisholm|first=Roderick|title=Person and Object|publisher=Open Court|year=1976}}</ref> He argues that these evidences, first person reporting and consciousness, are strong and should be innocent until proven guilty. He offers thought experiments as evidence including the surgery example and the use of Leibniz's Law ([[Identity of indiscernibles]]).

The surgery thought experiment (attributed to [[Charles Sanders Peirce]]) runs like this. Imagine you could save a substantial amount of money by undergoing surgery without an anesthesia. Instead, you will be given drugs afterwards that cause amnesia of the whole experience. You ask your friends and family what to do and they encourage you to skip the anesthesia and save the money. They have come up with a solution to help you avoid the pain of undergoing the surgery fully aware: <blockquote>"Have no fear,” they will say. “Take the cheaper operation and we will take care of everything. We will lay down the convention that the man on the table is not you, Jones, but is Smith.” What ''ought'' to be obvious to you, it seems to me, is that the laying down of this convention should have no effect at all upon your decision. For you may still ask, “But won’t that person be I?” and, it seems to me, the question has an answer.<ref name=":0" /> </blockquote>Chisholm's point is that our identity and persistence as person is not like the mere convention of the loose persistence of vulgar objects. Regardless of the convention, you will still experience the pain of the surgery. This is meant to strengthen his position that person's have strict philosophical persistence and are ''ens per se'' and not merely ''ens per alio.'' Persons are entities in themselves; vulgar objects are merely entities through another, or by entities by mere convention. Hence, if this thought experiment provides the intuition that we are not mere conventions, then mereological essentialism must be false for persons.

A second thought experiment is modal. It asks whether I, as a person, can persist with my identity through the loss of a hand.<ref>{{Cite journal|last=Chisholm|first=Roderick|date=1991|title=On the Simplicity of the Soul|journal=Philosophical Perspectives|volume=5|pages=157–181|doi=10.2307/2214094 |jstor=2214094 }}</ref> The answer according to first person reporting and the experience of consciousness is yes. If I have survived the loss of my hand (a mereological part) then mereological essentialism cannot hold for persons. This applies to Leibniz's Law in the following way. If my body were identical to its collection of parts then the collection of parts could not survive the loss of my hand. Leibniz's Law therefore implies that either I must not merely be the collection of parts that was my body or I am no longer myself. The evidence of consciousness rules out the latter; therefore, mereological essentialism must be false for persons. If mereological essentialism held for persons, then I would have been annihilated along with my hand.