For discussion of the Body-Minus (Tib and Tibbles/Pezdelaneous and Pezminus/The statue guy/the cat with many tails/whatever)
(Admin note: What follows is the content of the first comment, which was accidentally deleted.)
Here is a recap of what has happened so far:
Steve: Is anyone writing about the Body-minus paradox? What do you think is the weakest premise and why? I separated the paradox into 4 premises and a conclusion. I found the premise "Both Body-minus and Tibbles exist after the accident" to be the weakest premise. I gave the following reasoning:Tibbles, in the sense used in premise (1) [the premise that states that both Tibbles and Body-minus exist before the accident], no longer exists. In premise (1), the word “Tibbles” means “The set of molecules composing the cat named ‘Tibbles.’” In premise (3) it is clear that “Tibbles” no longer refers to this same set of molecules. Instead, the sense of premise (3) is that “Tibbles” means “The set of all molecules composing Tibbles, except for the molecules composing the tail,” which is exactly how Body-minus would have to be defined in premise (1). Hence, the argument uses the word “Tibbles” to refer to two distinct objects, while assuming that the meaning of the word does not change.
Then steve said: Just a follow up....Strictly speaking, by my reasoning, that premise is OK. The one that fails is "Body-minus and Tibbles are identical after the accident." This may be true, but the author must explicity make clear what is meant by "Tibbles." By my interpretation, this premise is false.
Then myself (howeman, Brendan whatever) said: (First of all, I assume that our conclusion is that a paradox exists?) The point about Tibbles (from my understanding), is that the cat continues to exist as a cat, even without his tail. Thus, Tibbles and body-minus are identical.Personally, I dont' think body-minus is a paradox at all. 1. If you can't have 2 objects occupy the same space at teh same time, then the initial set up of the problem is the flaw, becuase body-minus is in teh same space as tibbles. 2. What this really is is an exercise in names, just like the statue. If I call an object Bob, and someone else calls it Sally, then I guess we must have a paradox because two identical objects in the same space. The statue is a little more entertaining, but it's still really all semantics. I suppose the Theseus is also the same in the end, but I enjoy it more and I think it poses a more interesting problem.
Then steve replyed: Howeman, 1. If you can't have 2 objects occupy the same space at teh same time, then the initial set up of the problem is the flaw, becuase body-minus is in teh same space as tibbles. That's really a brilliant observation... I agree that there's no paradox. However, I wasn't able to put the reason why into such clear terms. It appears to be merely a matter of semantics. Actually, I had at first wanted to attack the first premise, that Body-minus exists before the accident, because just giving a name to something doesn't necessarily make it exist. In fact, you are correct: Body-minus isn't so much distinct from Tibbles, as it is a part of Tibbles. P.S. thanks for the compliment steve
Then Chris added: This is a nice discussion of the Tib-Tibbles case. Hopefully we can address some of these issues in class. (There were some other things said about making this thread, so I did)